merge origin/main into morefiles, resolve all conflicts

android/app/build.gradle.kts

@@ -1,7 +1,25 @@
+import java.util.Properties
+
 plugins {
     alias(libs.plugins.android.application)
+    alias(libs.plugins.hilt)
+    alias(libs.plugins.navigation.safeargs)
 }
 
+val localProperties = Properties().apply {
+    val file = rootProject.file("local.properties")
+    if (file.exists()) {
+        file.inputStream().use { load(it) }
+    }
+}
+
+fun quoted(value: String): String = "\"$value\""
+
+val emulatorBackendUrl =
+    (localProperties.getProperty("petstore.backend.emulatorUrl") ?: "http://10.0.2.2:8080/").trim()
+val deviceBackendUrl =
+    (localProperties.getProperty("petstore.backend.deviceUrl") ?: "http://10.0.0.200:8080/").trim()
+
 android {
     namespace = "com.example.petstoremobile"
     compileSdk = 36
@@ -14,6 +32,14 @@ android {
         versionName = "1.0"
 
         testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
+
+        buildConfigField("String", "EMULATOR_BACKEND_URL", quoted(emulatorBackendUrl))
+        buildConfigField("String", "DEVICE_BACKEND_URL", quoted(deviceBackendUrl))
+    }
+
+    buildFeatures {
+        buildConfig = true
+        viewBinding = true
     }
 
     buildTypes {
@@ -32,34 +58,46 @@ android {
 }
 
 dependencies {
+    // Core AndroidX & UI
     implementation(libs.appcompat)
     implementation(libs.material)
     implementation(libs.activity)
     implementation(libs.constraintlayout)
-
-    implementation("com.squareup.retrofit2:retrofit:2.9.0")
-    implementation("com.squareup.retrofit2:converter-gson:2.9.0")
-    implementation("com.squareup.okhttp3:logging-interceptor:4.12.0")
-    implementation("com.squareup.okhttp3:okhttp:4.12.0")
-
-    implementation("com.google.android.material:material:1.11.0")
-    implementation("androidx.viewpager2:viewpager2:1.1.0")
-
-    implementation("androidx.camera:camera-core:1.4.0")
-    implementation("androidx.camera:camera-camera2:1.4.0")
-    implementation("androidx.camera:camera-lifecycle:1.4.0")
-    implementation("androidx.camera:camera-view:1.4.0")
-    implementation("androidx.swiperefreshlayout:swiperefreshlayout:1.1.0")
     implementation(libs.swiperefreshlayout)
+    implementation(libs.viewpager2)
 
+    // Hilt Dependency Injection
+    implementation(libs.hilt.android)
+    annotationProcessor(libs.hilt.compiler)
+
+    // Navigation Component
+    implementation(libs.navigation.fragment)
+    implementation(libs.navigation.ui)
+
+    // Networking
+    implementation(libs.retrofit)
+    implementation(libs.retrofit.gson)
+    implementation(libs.okhttp)
+    implementation(libs.okhttp.logging)
+
+    // CameraX
+    implementation(libs.camera.core)
+    implementation(libs.camera.camera2)
+    implementation(libs.camera.lifecycle)
+    implementation(libs.camera.view)
+
+    // Image Loading
+    implementation(libs.glide)
+    annotationProcessor(libs.glide.compiler)
+
+    // Other Third-party Libraries
     implementation("com.github.NaikSoftware:StompProtocolAndroid:1.6.6")
     implementation("io.reactivex.rxjava2:rxjava:2.2.21")
     implementation("io.reactivex.rxjava2:rxandroid:2.1.1")
+    implementation("com.github.prolificinteractive:material-calendarview:2.0.1")
 
-    implementation("com.github.bumptech.glide:glide:4.16.0")
-    annotationProcessor("com.github.bumptech.glide:compiler:4.16.0")
-
+    // Testing
     testImplementation(libs.junit)
     androidTestImplementation(libs.ext.junit)
     androidTestImplementation(libs.espresso.core)
-}
+}

android/app/src/main/java/com/example/petstoremobile/PetStoreApplication.java

@@ -1,8 +1,9 @@
 package com.example.petstoremobile;
 
 import android.app.Application;
-import com.example.petstoremobile.api.auth.TokenManager;
+import dagger.hilt.android.HiltAndroidApp;
 
+@HiltAndroidApp
 public class PetStoreApplication extends Application {
     @Override
     public void onCreate() {

android/app/src/main/java/com/example/petstoremobile/activities/HomeActivity.java

@@ -10,23 +10,25 @@ import android.util.Log;
 import androidx.activity.EdgeToEdge;
 import androidx.activity.result.ActivityResultLauncher;
 import androidx.activity.result.contract.ActivityResultContracts;
-import androidx.annotation.NonNull;
 import androidx.appcompat.app.AppCompatActivity;
 import androidx.core.content.ContextCompat;
 import androidx.core.graphics.Insets;
 import androidx.core.view.ViewCompat;
 import androidx.core.view.WindowInsetsCompat;
-import androidx.fragment.app.Fragment;
+import androidx.navigation.NavController;
+import androidx.navigation.fragment.NavHostFragment;
+import androidx.navigation.ui.NavigationUI;
 
 import com.example.petstoremobile.R;
-import com.example.petstoremobile.fragments.ChatFragment;
-import com.example.petstoremobile.fragments.ListFragment;
-import com.example.petstoremobile.fragments.ProfileFragment;
+import com.example.petstoremobile.databinding.ActivityHomeBinding;
 import com.example.petstoremobile.services.ChatNotificationService;
-import com.google.android.material.bottomnavigation.BottomNavigationView;
 
+import dagger.hilt.android.AndroidEntryPoint;
+
+@AndroidEntryPoint
 public class HomeActivity extends AppCompatActivity {
-    private BottomNavigationView bottomNav;
+    private ActivityHomeBinding binding;
+    private NavController navController;
 
     // Launcher to ask for notification permission
     private final ActivityResultLauncher<String> requestPermissionLauncher =
@@ -36,81 +38,73 @@ public class HomeActivity extends AppCompatActivity {
                 }
             });
 
+    /**
+     * Sets up the home screen, initializes bottom navigation, and handles incoming navigation intents.
+     */
     @Override
     protected void onCreate(Bundle savedInstanceState) {
+        EdgeToEdge.enable(this);
         super.onCreate(savedInstanceState);
-        setContentView(R.layout.activity_home);
+        binding = ActivityHomeBinding.inflate(getLayoutInflater());
+        setContentView(binding.getRoot());
+
+        ViewCompat.setOnApplyWindowInsetsListener(binding.main, (v, insets) -> {
+            Insets systemBars = insets.getInsets(WindowInsetsCompat.Type.systemBars());
+            v.setPadding(systemBars.left, systemBars.top, systemBars.right, systemBars.bottom);
+            return insets;
+        });
+
+        // Initialize Navigation Component
+        NavHostFragment navHostFragment = (NavHostFragment) getSupportFragmentManager()
+                .findFragmentById(R.id.nav_host_fragment);
+        if (navHostFragment != null) {
+            navController = navHostFragment.getNavController();
+            NavigationUI.setupWithNavController(binding.bottomNavigation, navController);
+        }
 
-        //get the bottom navbar from the layout
-        bottomNav = findViewById(R.id.bottom_navigation);
-        
         //load the list fragment by default if it's a fresh start
         if (savedInstanceState == null) {
             handleIntent(getIntent());
         }
 
-        //when an item in the bottom bar is selected, load the corresponding fragment
-        bottomNav.setOnItemSelectedListener(item -> {
-            if (item.getItemId() == R.id.nav_list) {
-                loadFragment(new ListFragment());
-                return true;
-            } else if (item.getItemId() == R.id.nav_chat) {
-                loadFragment(new ChatFragment());
-                return true;
-            } else if (item.getItemId() == R.id.nav_profile) {
-                loadFragment(new ProfileFragment());
-                return true;
-            }
-            return false;
-        });
-
         // Start the notification service and request for notification permission
         startNotificationService();
         requestNotificationPermission();
     }
     
-    // Handle new intents when the activity is already running,
-    // like clicking a notification while the app is in use
+    /**
+     * Handles new intents received while the activity is already running (like notifications).
+     */
     @Override
     protected void onNewIntent(Intent intent) {
         super.onNewIntent(intent);
+        setIntent(intent); // Set the new intent so fragments can access updated extras
         handleIntent(intent);
     }
 
-    // Helper function to process intents for navigation.
-    // like clicking a notification or just launching the app from a fresh start
+    /**
+     * Processes the intent to determine if specific navigation (like opening a chat) is required.
+     */
     private void handleIntent(Intent intent) {
         if (intent != null && "chat".equals(intent.getStringExtra("navigate_to"))) {
-            ChatFragment chatFragment = new ChatFragment();
-            if (intent.hasExtra("conversation_id")) {
-                Bundle args = new Bundle();
-                args.putLong("conversation_id", intent.getLongExtra("conversation_id", -1));
-                chatFragment.setArguments(args);
+            if (binding.bottomNavigation != null) {
+                // Navigate by selecting the bottom nav item.
+                binding.bottomNavigation.setSelectedItemId(R.id.nav_chat);
             }
-            loadFragment(chatFragment);
-            bottomNav.setSelectedItemId(R.id.nav_chat);
-        } else {
-            new android.os.Handler().postDelayed(() -> {
-                loadFragment(new ListFragment());
-                bottomNav.setSelectedItemId(R.id.nav_list);
-            }, 100);
         }
     }
 
-    // Helper function to start the notification service in the background
-    // to receive notifications when a new conversation is created
+    /**
+     * Starts the background service responsible for monitoring chat notifications.
+     */
     private void startNotificationService() {
-        new Thread(() -> {
-            try {
-                Intent serviceIntent = new Intent(this, ChatNotificationService.class);
-                startService(serviceIntent);
-            } catch (Exception e) {
-                Log.e("HomeActivity", "Failed to start notification service: " + e.getMessage());
-            }
-        }).start();
+        Intent serviceIntent = new Intent(this, ChatNotificationService.class);
+        startService(serviceIntent);
     }
 
-    //Helper function to request for notification permission
+    /**
+     * Requests POST_NOTIFICATIONS permission from the user if running on Android 13 and above.
+     */
     private void requestNotificationPermission() {
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) {
             if (ContextCompat.checkSelfPermission(this, Manifest.permission.POST_NOTIFICATIONS) != PackageManager.PERMISSION_GRANTED) {
@@ -118,12 +112,4 @@ public class HomeActivity extends AppCompatActivity {
             }
         }
     }
-
-    //Helper function to load a fragment
-    private void loadFragment(Fragment fragment) {
-        getSupportFragmentManager()
-                .beginTransaction()
-                .replace(R.id.fragment_container, fragment)
-                .commit();
-    }
 }

android/app/src/main/java/com/example/petstoremobile/activities/MainActivity.java

@@ -2,10 +2,7 @@ package com.example.petstoremobile.activities;
 
 import android.content.Intent;
 import android.os.Bundle;
-import android.util.Log;
-import android.widget.Button;
-import android.widget.EditText;
-import android.widget.TextView;
+import android.view.inputmethod.EditorInfo;
 import android.widget.Toast;
 
 import androidx.activity.EdgeToEdge;
@@ -13,157 +10,134 @@ import androidx.appcompat.app.AppCompatActivity;
 import androidx.core.graphics.Insets;
 import androidx.core.view.ViewCompat;
 import androidx.core.view.WindowInsetsCompat;
+import androidx.lifecycle.ViewModelProvider;
 
-import com.example.petstoremobile.R;
-import com.example.petstoremobile.api.auth.AuthApi;
 import com.example.petstoremobile.api.auth.TokenManager;
-import com.example.petstoremobile.api.RetrofitClient;
-import com.example.petstoremobile.dtos.AuthDTO;
-import com.example.petstoremobile.dtos.UserDTO;
+import com.example.petstoremobile.databinding.ActivityMainBinding;
+import com.example.petstoremobile.viewmodels.AuthViewModel;
+import com.example.petstoremobile.utils.Resource;
 
-import retrofit2.Call;
-import retrofit2.Callback;
-import retrofit2.Response;
+import javax.inject.Inject;
+import javax.inject.Named;
+
+import dagger.hilt.android.AndroidEntryPoint;
 
 //The login screen activity
+@AndroidEntryPoint
 public class MainActivity extends AppCompatActivity {
 
-    private EditText etUser;
-    private EditText etPassword;
-    private Button btnLogin;
-    private TextView tvLoginStatus;
+    private ActivityMainBinding binding;
+    private AuthViewModel viewModel;
 
+    @Inject TokenManager tokenManager;
+    @Inject @Named("baseUrl") String baseUrl;
 
+    /**
+     * Initializes the activity, sets up the UI, and checks for an existing login session.
+     */
     @Override
     protected void onCreate(Bundle savedInstanceState) {
+        EdgeToEdge.enable(this);
         super.onCreate(savedInstanceState);
 
         // Check if user is already logged in
-        TokenManager tokenManager = TokenManager.getInstance(this);
         if (tokenManager.isLoggedIn()) {
             if ("CUSTOMER".equalsIgnoreCase(tokenManager.getRole())) {
                 // If a customer somehow remained logged in, clear them out
                 tokenManager.clearLoginData();
             } else {
-                Intent intent = new Intent(this, HomeActivity.class);
-                startActivity(intent);
+                startActivity(new Intent(this, HomeActivity.class));
                 finish();
                 return;
             }
         }
 
-        setContentView(R.layout.activity_main);
+        binding = ActivityMainBinding.inflate(getLayoutInflater());
+        setContentView(binding.getRoot());
+        viewModel = new ViewModelProvider(this).get(AuthViewModel.class);
+
+        ViewCompat.setOnApplyWindowInsetsListener(binding.main, (v, insets) -> {
+            Insets systemBars = insets.getInsets(WindowInsetsCompat.Type.systemBars());
+            v.setPadding(systemBars.left, systemBars.top, systemBars.right, systemBars.bottom);
+            return insets;
+        });
 
-        //get all controls from layout
-        tvLoginStatus = findViewById(R.id.tvLoginStatus);
-        etUser     = findViewById(R.id.etUser);
-        etPassword = findViewById(R.id.etPassword);
-        btnLogin   = findViewById(R.id.btnLogin);
         //clear login status
-        tvLoginStatus.setText("");
+        binding.tvLoginStatus.setText("");
+
+        // Set editor action listener for password field to login on when enter is pressed
+        binding.etPassword.setOnEditorActionListener((v, actionId, event) -> {
+            if (actionId == EditorInfo.IME_ACTION_DONE || actionId == EditorInfo.IME_NULL) {
+                binding.btnLogin.performClick();
+                return true;
+            }
+            return false;
+        });
 
         //Set click listener for login button
-        btnLogin.setOnClickListener(v -> {
+        binding.btnLogin.setOnClickListener(v -> {
             //Get username and password from text fields
-            String username = etUser.getText().toString();
-            String password = etPassword.getText().toString();
+            String username = binding.etUser.getText().toString();
+            String password = binding.etPassword.getText().toString();
 
             //check if fields are empty
             if (username.isEmpty() || password.isEmpty()) {
                 Toast.makeText(this, "Please enter username and password", Toast.LENGTH_SHORT).show();
-                tvLoginStatus.setText("Please enter username and password");
+                binding.tvLoginStatus.setText("Please enter username and password");
                 return;
             }
 
-            AuthApi authApi = RetrofitClient.getAuthApi(this);
+            performLogin(username, password);
+        });
+    }
 
-            //Call login from api and get response
-            authApi.login(new AuthDTO.LoginRequest(username,password)).enqueue(new Callback<AuthDTO.LoginResponse>() {
-                @Override
-                public void onResponse(Call<AuthDTO.LoginResponse> call, Response<AuthDTO.LoginResponse> response) {
-                    if (response.isSuccessful() && response.body() != null) {
-                        String role = response.body().getRole();
+    /**
+     * Executes the login process using the AuthViewModel and handles the authentication response.
+     */
+    private void performLogin(String username, String password) {
+        viewModel.login(username, password).observe(this, resource -> {
+            if (resource == null) return;
 
-                        // Check if the user is a CUSTOMER and deny login if so
+            switch (resource.status) {
+                case LOADING:
+                    binding.btnLogin.setEnabled(false);
+                    binding.tvLoginStatus.setText("Logging in...");
+                    break;
+                case SUCCESS:
+                    if (resource.data != null) {
+                        String role = resource.data.getRole();
                         if ("CUSTOMER".equalsIgnoreCase(role)) {
-                            Toast.makeText(MainActivity.this, "Access denied: Customers are not allowed to log in.", Toast.LENGTH_LONG).show();
-                            tvLoginStatus.setText("Customers are not allowed to log in");
-                            return;
+                            binding.btnLogin.setEnabled(true);
+                            binding.tvLoginStatus.setText("Customers are not allowed to log in");
+                            Toast.makeText(this, "Access denied: Customers are not allowed to log in.", Toast.LENGTH_LONG).show();
+                        } else {
+                            tokenManager.saveLoginData(resource.data.getToken(), resource.data.getUsername(), role);
+                            fetchUserIdAndNavigate();
                         }
-
-                        //save login data in shared preferences
-                        TokenManager.getInstance(MainActivity.this).saveLoginData(
-                                response.body().getToken(),
-                                response.body().getUsername(),
-                                role
-                        );
-
-                        //fetch user id from api then login to home activity
-                        RetrofitClient.getAuthApi(MainActivity.this).getMe()
-                                .enqueue(new Callback<UserDTO>() {
-                                    @Override
-                                    public void onResponse(Call<UserDTO> call,
-                                                           Response<UserDTO> response) {
-                                        if (response.isSuccessful() && response.body() != null) {
-                                            TokenManager.getInstance(MainActivity.this)
-                                                    .saveUserId(response.body().getId());
-                                        }
-
-                                        Toast.makeText(MainActivity.this, "Login successful", Toast.LENGTH_SHORT).show();
-                                        startActivity(new Intent(MainActivity.this, HomeActivity.class));
-                                        finish();
-                                    }
-
-                                    @Override
-                                    public void onFailure(Call<UserDTO> call,
-                                                          Throwable t) {
-                                        Log.e("MainActivity", "Failed to fetch userId", t);
-
-                                        Toast.makeText(MainActivity.this, "Login successful", Toast.LENGTH_SHORT).show();
-                                        startActivity(new Intent(MainActivity.this, HomeActivity.class));
-                                        finish();
-                                    }
-                                });
-                    } else {
-                        String errorMessage;
-                        switch (response.code()) {
-                            case 401:
-                                errorMessage = "Invalid username or password";
-                                break;
-                            case 500:
-                                errorMessage = "Server error. Please try again later.";
-                                break;
-                            case 503:
-                                errorMessage = "Service unavailable. Backend may be starting up.";
-                                break;
-                            default:
-                                errorMessage = "Login failed (Error " + response.code() + ")";
-                        }
-                        Toast.makeText(MainActivity.this, errorMessage, Toast.LENGTH_LONG).show();
-                        tvLoginStatus.setText(errorMessage);
                     }
+                    break;
+                case ERROR:
+                    binding.btnLogin.setEnabled(true);
+                    binding.tvLoginStatus.setText(resource.message);
+                    Toast.makeText(this, resource.message, Toast.LENGTH_LONG).show();
+                    break;
+            }
+        });
+    }
+
+    /**
+     * Retrieves the logged-in user's profile information to save their ID before navigating to the home screen.
+     */
+    private void fetchUserIdAndNavigate() {
+        viewModel.getMe().observe(this, resource -> {
+            if (resource != null && resource.status != Resource.Status.LOADING) {
+                if (resource.status == Resource.Status.SUCCESS && resource.data != null) {
+                    tokenManager.saveUserId(resource.data.getId());
                 }
-
-                @Override
-                public void onFailure(Call<AuthDTO.LoginResponse> call, Throwable t) {
-                    Log.e("MainActivity", "Login request failed", t);
-
-                    String errorMessage;
-                    if (t instanceof java.net.ConnectException ||
-                        t instanceof java.net.SocketTimeoutException ||
-                        t instanceof java.net.UnknownHostException) {
-                        errorMessage = "Cannot connect to server at " + RetrofitClient.BASE_URL +
-                                ". Please check if the backend is running.";
-                    } else if (t instanceof java.io.IOException) {
-                        errorMessage = "Network error. Please check your connection.";
-                    } else {
-                        errorMessage = "Login failed: " + t.getMessage();
-                    }
-
-                    Toast.makeText(MainActivity.this, errorMessage, Toast.LENGTH_LONG).show();
-                    tvLoginStatus.setText(errorMessage);
-                }
-            });
+                Toast.makeText(this, "Login successful", Toast.LENGTH_SHORT).show();
+                startActivity(new Intent(this, HomeActivity.class));
+                finish();
+            }
         });
     }
 }

android/app/src/main/java/com/example/petstoremobile/adapters/AdoptionAdapter.java

@@ -1,81 +1,128 @@
 package com.example.petstoremobile.adapters;
 
 import android.graphics.Color;
-import android.view.*;
-import android.widget.TextView;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
 import androidx.annotation.NonNull;
 import androidx.recyclerview.widget.RecyclerView;
-import com.example.petstoremobile.R;
+import com.example.petstoremobile.databinding.ItemAdoptionBinding;
 import com.example.petstoremobile.dtos.AdoptionDTO;
+import com.example.petstoremobile.utils.BulkDeleteHandler;
+import com.example.petstoremobile.utils.SelectionHelper;
 import java.util.List;
 
-public class AdoptionAdapter extends RecyclerView.Adapter<AdoptionAdapter.AdoptionViewHolder> {
+public class AdoptionAdapter extends RecyclerView.Adapter<AdoptionAdapter.AdoptionViewHolder> implements BulkDeleteHandler.SelectableAdapter {
 
     private List<AdoptionDTO> adoptionList;
     private OnAdoptionClickListener listener;
+    private final SelectionHelper selectionHelper;
 
     public interface OnAdoptionClickListener {
         void onAdoptionClick(int position);
+        void onSelectionChanged(int count);
     }
 
     public AdoptionAdapter(List<AdoptionDTO> adoptionList, OnAdoptionClickListener listener) {
         this.adoptionList = adoptionList;
         this.listener = listener;
+        this.selectionHelper = new SelectionHelper(new SelectionHelper.SelectionListener() {
+            @Override
+            public void onSelectionChanged(int count) {
+                listener.onSelectionChanged(count);
+            }
+
+            @Override
+            public void onSelectionModeToggle(boolean selectionMode) {
+                notifyDataSetChanged();
+            }
+        });
+    }
+
+    @Override
+    public List<String> getSelectedKeys() {
+        return selectionHelper.getSelectedKeys();
+    }
+
+    @Override
+    public void clearSelection() {
+        selectionHelper.clearSelection();
     }
 
     public static class AdoptionViewHolder extends RecyclerView.ViewHolder {
-        TextView tvCustomerName, tvPetName, tvDate, tvEmployee, tvFee, tvStatus;
+        final ItemAdoptionBinding binding;
 
-        public AdoptionViewHolder(@NonNull View v) {
-            super(v);
-            tvCustomerName = v.findViewById(R.id.tvAdoptionCustomerName);
-            tvPetName      = v.findViewById(R.id.tvAdoptionPetName);
-            tvDate         = v.findViewById(R.id.tvAdoptionDate);
-            tvEmployee = v.findViewById(R.id.tvAdoptionEmployee);
-            tvFee          = v.findViewById(R.id.tvAdoptionFee);
-            tvStatus       = v.findViewById(R.id.tvAdoptionStatus);
+        public AdoptionViewHolder(@NonNull ItemAdoptionBinding binding) {
+            super(binding.getRoot());
+            this.binding = binding;
         }
     }
 
     @NonNull
     @Override
     public AdoptionViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
-        View v = LayoutInflater.from(parent.getContext())
-                .inflate(R.layout.item_adoption, parent, false);
-        return new AdoptionViewHolder(v);
+        ItemAdoptionBinding binding = ItemAdoptionBinding.inflate(LayoutInflater.from(parent.getContext()), parent, false);
+        return new AdoptionViewHolder(binding);
     }
 
     @Override
     public void onBindViewHolder(@NonNull AdoptionViewHolder holder, int position) {
         AdoptionDTO a = adoptionList.get(position);
+        ItemAdoptionBinding binding = holder.binding;
+
+        binding.tvAdoptionCustomerName.setText(a.getCustomerName() != null ? a.getCustomerName() : "");
+        binding.tvAdoptionPetName.setText("Pet: " + (a.getPetName() != null ? a.getPetName() : ""));
+        binding.tvAdoptionStaffName.setText("Staff: " + (a.getEmployeeName() != null ? a.getEmployeeName() : "N/A"));
+        binding.tvAdoptionDate.setText("Date: " + (a.getAdoptionDate() != null ? a.getAdoptionDate() : ""));
+        binding.tvAdoptionFee.setText(a.getAdoptionFee() != null ? "$" + a.getAdoptionFee() : "");
+
 
-        holder.tvCustomerName.setText(a.getCustomerName() != null ? a.getCustomerName() : "");
-        holder.tvPetName.setText("Pet: " + (a.getPetName() != null ? a.getPetName() : ""));
-        holder.tvDate.setText("Date: " + (a.getAdoptionDate() != null ? a.getAdoptionDate() : ""));
-        holder.tvFee.setText(a.getAdoptionFee() != null ? "$" + a.getAdoptionFee() : "");
-        holder.tvEmployee.setText("Staff: " +
-                (a.getEmployeeName() != null ? a.getEmployeeName() : "Unassigned"));
         String status = a.getAdoptionStatus() != null ? a.getAdoptionStatus() : "";
-        holder.tvStatus.setText(status);
+        binding.tvAdoptionStatus.setText(status);
 
         switch (status) {
-            case "Approved":
-                holder.tvStatus.setBackgroundColor(Color.parseColor("#4CAF50"));
+            case "Completed":
+                binding.tvAdoptionStatus.setBackgroundColor(Color.parseColor("#4CAF50"));
                 break;
             case "Pending":
-                holder.tvStatus.setBackgroundColor(Color.parseColor("#FF9800"));
+                binding.tvAdoptionStatus.setBackgroundColor(Color.parseColor("#FF9800"));
                 break;
-            case "Rejected":
-                holder.tvStatus.setBackgroundColor(Color.parseColor("#F44336"));
+            case "Cancelled":
+                binding.tvAdoptionStatus.setBackgroundColor(Color.parseColor("#F44336"));
                 break;
             default:
-                holder.tvStatus.setBackgroundColor(Color.parseColor("#9E9E9E"));
+                binding.tvAdoptionStatus.setBackgroundColor(Color.parseColor("#9E9E9E"));
                 break;
         }
 
-        holder.itemView.setOnClickListener(v -> listener.onAdoptionClick(position));
+        String key = String.valueOf(a.getAdoptionId());
+
+        // Bulk delete selection mode
+        if (selectionHelper.isInSelectionMode()) {
+            binding.cbSelectAdoption.setVisibility(View.VISIBLE);
+            binding.cbSelectAdoption.setChecked(selectionHelper.isSelected(key));
+        } else {
+            binding.cbSelectAdoption.setVisibility(View.GONE);
+            binding.cbSelectAdoption.setChecked(false);
+        }
+
+        holder.itemView.setOnClickListener(v -> {
+            if (selectionHelper.isInSelectionMode()) {
+                selectionHelper.toggleSelection(key);
+                notifyItemChanged(position);
+            } else {
+                listener.onAdoptionClick(position);
+            }
+        });
+
+        holder.itemView.setOnLongClickListener(v -> {
+            if (!selectionHelper.isInSelectionMode()) {
+                selectionHelper.startSelection(key);
+            }
+            return true;
+        });
     }
 
     @Override
     public int getItemCount() { return adoptionList.size(); }
-}
+}

android/app/src/main/java/com/example/petstoremobile/adapters/AppointmentAdapter.java

@@ -4,79 +4,124 @@ import android.graphics.Color;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
-import android.widget.TextView;
 import androidx.annotation.NonNull;
 import androidx.recyclerview.widget.RecyclerView;
-import com.example.petstoremobile.R;
+import com.example.petstoremobile.databinding.ItemAppointmentBinding;
 import com.example.petstoremobile.dtos.AppointmentDTO;
+import com.example.petstoremobile.utils.BulkDeleteHandler;
+import com.example.petstoremobile.utils.SelectionHelper;
 import java.util.List;
 
-public class AppointmentAdapter extends RecyclerView.Adapter<AppointmentAdapter.AppointmentViewHolder> {
+public class AppointmentAdapter extends RecyclerView.Adapter<AppointmentAdapter.AppointmentViewHolder> implements BulkDeleteHandler.SelectableAdapter {
 
     private List<AppointmentDTO> appointmentList;
     private OnAppointmentClickListener appointmentClickListener;
+    private final SelectionHelper selectionHelper;
 
     public interface OnAppointmentClickListener {
         void onAppointmentClick(int position);
+        void onSelectionChanged(int count);
     }
 
     public AppointmentAdapter(List<AppointmentDTO> appointmentList,
                               OnAppointmentClickListener appointmentClickListener) {
         this.appointmentList = appointmentList;
         this.appointmentClickListener = appointmentClickListener;
+        this.selectionHelper = new SelectionHelper(new SelectionHelper.SelectionListener() {
+            @Override
+            public void onSelectionChanged(int count) {
+                appointmentClickListener.onSelectionChanged(count);
+            }
+
+            @Override
+            public void onSelectionModeToggle(boolean selectionMode) {
+                notifyDataSetChanged();
+            }
+        });
+    }
+
+    @Override
+    public List<String> getSelectedKeys() {
+        return selectionHelper.getSelectedKeys();
+    }
+
+    @Override
+    public void clearSelection() {
+        selectionHelper.clearSelection();
     }
 
     public static class AppointmentViewHolder extends RecyclerView.ViewHolder {
-        TextView tvCustomerName, tvPetName, tvServiceType, tvDateTime,tvEmployee, tvAppointmentStatus;
+        private final ItemAppointmentBinding binding;
 
-        public AppointmentViewHolder(@NonNull View v) {
-            super(v);
-            tvCustomerName = v.findViewById(R.id.tvCustomerName);
-            tvPetName = v.findViewById(R.id.tvApptPetName);
-            tvServiceType = v.findViewById(R.id.tvServiceType);
-            tvDateTime = v.findViewById(R.id.tvDateTime);
-
-            tvAppointmentStatus = v.findViewById(R.id.tvAppointmentStatus);
+        public AppointmentViewHolder(@NonNull ItemAppointmentBinding binding) {
+            super(binding.getRoot());
+            this.binding = binding;
         }
     }
 
     @NonNull
     @Override
     public AppointmentViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
-        View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_appointment, parent, false);
-        return new AppointmentViewHolder(v);
+        ItemAppointmentBinding binding = ItemAppointmentBinding.inflate(LayoutInflater.from(parent.getContext()), parent, false);
+        return new AppointmentViewHolder(binding);
     }
 
     @Override
     public void onBindViewHolder(@NonNull AppointmentViewHolder holder, int position) {
         AppointmentDTO a = appointmentList.get(position);
+        ItemAppointmentBinding binding = holder.binding;
 
-        holder.tvCustomerName.setText(a.getCustomerName() != null ? a.getCustomerName() : "");
-        holder.tvPetName.setText("Pet: " + (a.getPetName() != null ? a.getPetName() : ""));
-        holder.tvServiceType.setText(a.getServiceType() != null ? a.getServiceType() : "");
-        holder.tvDateTime.setText((a.getAppointmentDate() != null ? a.getAppointmentDate() : "") +
+        binding.tvCustomerName.setText(a.getCustomerName() != null ? a.getCustomerName() : "");
+        binding.tvApptPetName.setText("Pet: " + (a.getPetName() != null ? a.getPetName() : ""));
+        binding.tvServiceType.setText(a.getServiceType() != null ? a.getServiceType() : "");
+        binding.tvStaffName.setText("Staff: " + (a.getEmployeeName() != null ? a.getEmployeeName() : "Unassigned"));
+        binding.tvDateTime.setText((a.getAppointmentDate() != null ? a.getAppointmentDate() : "") +
                 " at " + (a.getAppointmentTime() != null ? a.getAppointmentTime() : ""));
-        holder.tvEmployee.setText("Staff: " + (a.getEmployeeName() != null ? a.getEmployeeName() : ""));
 
         String status = a.getStatus() != null ? a.getStatus() : "";
-        holder.tvAppointmentStatus.setText(status);
+        binding.tvAppointmentStatus.setText(status);
 
-        switch (status) {
-            case "Booked":
-                holder.tvAppointmentStatus.setBackgroundColor(Color.parseColor("#2196F3")); // blue
+        switch (status.toUpperCase()) {
+            case "BOOKED":
+                binding.tvAppointmentStatus.setBackgroundColor(Color.parseColor("#2196F3")); // blue
                 break;
-            case "Completed":
-                holder.tvAppointmentStatus.setBackgroundColor(Color.parseColor("#4CAF50")); // green
+            case "COMPLETED":
+                binding.tvAppointmentStatus.setBackgroundColor(Color.parseColor("#4CAF50")); // green
                 break;
-            case "Cancelled":
-                holder.tvAppointmentStatus.setBackgroundColor(Color.parseColor("#F44336")); // red
+            case "CANCELLED":
+                binding.tvAppointmentStatus.setBackgroundColor(Color.parseColor("#F44336")); // red
                 break;
             default:
-                holder.tvAppointmentStatus.setBackgroundColor(Color.parseColor("#9E9E9E")); // gray
+                binding.tvAppointmentStatus.setBackgroundColor(Color.parseColor("#9E9E9E")); // gray
                 break;
         }
 
-        holder.itemView.setOnClickListener(v -> appointmentClickListener.onAppointmentClick(position));
+        String key = String.valueOf(a.getAppointmentId());
+
+        // Bulk delete selection mode
+        if (selectionHelper.isInSelectionMode()) {
+            binding.cbSelectAppointment.setVisibility(View.VISIBLE);
+            binding.cbSelectAppointment.setChecked(selectionHelper.isSelected(key));
+        } else {
+            binding.cbSelectAppointment.setVisibility(View.GONE);
+            binding.cbSelectAppointment.setChecked(false);
+        }
+
+        holder.itemView.setOnClickListener(v -> {
+            if (selectionHelper.isInSelectionMode()) {
+                selectionHelper.toggleSelection(key);
+                notifyItemChanged(position);
+            } else {
+                appointmentClickListener.onAppointmentClick(position);
+            }
+        });
+
+        holder.itemView.setOnLongClickListener(v -> {
+            if (!selectionHelper.isInSelectionMode()) {
+                selectionHelper.startSelection(key);
+            }
+            return true;
+        });
     }
 
     @Override

android/app/src/main/java/com/example/petstoremobile/adapters/BlackTextArrayAdapter.java

@@ -0,0 +1,44 @@
+package com.example.petstoremobile.adapters;
+
+import android.content.Context;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.ArrayAdapter;
+import android.widget.TextView;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.core.content.ContextCompat;
+import com.example.petstoremobile.R;
+import java.util.List;
+
+// A class that overrides the arrayAdapter so the text color changes based on theme
+public class BlackTextArrayAdapter<T> extends ArrayAdapter<T> {
+    public BlackTextArrayAdapter(@NonNull Context context, int resource, @NonNull T[] objects) {
+        super(context, resource, objects);
+    }
+
+    public BlackTextArrayAdapter(@NonNull Context context, int resource, @NonNull List<T> objects) {
+        super(context, resource, objects);
+    }
+
+    @NonNull
+    @Override
+    public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {
+        View view = super.getView(position, convertView, parent);
+        view.setBackgroundColor(ContextCompat.getColor(getContext(), R.color.white));
+        if (view instanceof TextView) {
+            ((TextView) view).setTextColor(ContextCompat.getColor(getContext(), R.color.spinner_text));
+        }
+        return view;
+    }
+    
+    @Override
+    public View getDropDownView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {
+        View view = super.getDropDownView(position, convertView, parent);
+        view.setBackgroundColor(ContextCompat.getColor(getContext(), R.color.white));
+        if (view instanceof TextView) {
+            ((TextView) view).setTextColor(ContextCompat.getColor(getContext(), R.color.spinner_text));
+        }
+        return view;
+    }
+}

android/app/src/main/java/com/example/petstoremobile/adapters/ChatAdapter.java

@@ -1,14 +1,12 @@
 package com.example.petstoremobile.adapters;
 
 import android.view.LayoutInflater;
-import android.view.View;
 import android.view.ViewGroup;
-import android.widget.TextView;
 
 import androidx.annotation.NonNull;
 import androidx.recyclerview.widget.RecyclerView;
 
-import com.example.petstoremobile.R;
+import com.example.petstoremobile.databinding.ItemChatBinding;
 import com.example.petstoremobile.models.Chat;
 
 import java.util.List;
@@ -30,15 +28,15 @@ public class ChatAdapter extends RecyclerView.Adapter<ChatAdapter.ChatViewHolder
     @NonNull
     @Override
     public ChatViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
-        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_chat, parent, false);
-        return new ChatViewHolder(view);
+        ItemChatBinding binding = ItemChatBinding.inflate(LayoutInflater.from(parent.getContext()), parent, false);
+        return new ChatViewHolder(binding);
     }
 
     @Override
     public void onBindViewHolder(@NonNull ChatViewHolder holder, int position) {
         Chat chat = chatList.get(position);
-        holder.tvCustomerName.setText(chat.getCustomerName());
-        holder.tvLastMessage.setText(chat.getLastMessage());
+        holder.binding.tvCustomerName.setText(chat.getCustomerName());
+        holder.binding.tvLastMessage.setText(chat.getLastMessage());
         holder.itemView.setOnClickListener(v -> listener.onChatClick(chat));
     }
 
@@ -48,12 +46,11 @@ public class ChatAdapter extends RecyclerView.Adapter<ChatAdapter.ChatViewHolder
     }
 
     public static class ChatViewHolder extends RecyclerView.ViewHolder {
-        TextView tvCustomerName, tvLastMessage;
+        final ItemChatBinding binding;
 
-        public ChatViewHolder(@NonNull View itemView) {
-            super(itemView);
-            tvCustomerName = itemView.findViewById(R.id.tvCustomerName);
-            tvLastMessage = itemView.findViewById(R.id.tvLastMessage);
+        public ChatViewHolder(@NonNull ItemChatBinding binding) {
+            super(binding.getRoot());
+            this.binding = binding;
         }
     }
 }

android/app/src/main/java/com/example/petstoremobile/adapters/InventoryAdapter.java

@@ -4,24 +4,22 @@ import android.graphics.Color;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
-import android.widget.CheckBox;
-import android.widget.TextView;
 
 import androidx.annotation.NonNull;
 import androidx.recyclerview.widget.RecyclerView;
 
-import com.example.petstoremobile.R;
+import com.example.petstoremobile.databinding.ItemInventoryBinding;
 import com.example.petstoremobile.dtos.InventoryDTO;
+import com.example.petstoremobile.utils.BulkDeleteHandler;
+import com.example.petstoremobile.utils.SelectionHelper;
 
-import java.util.ArrayList;
 import java.util.List;
 
-public class InventoryAdapter extends RecyclerView.Adapter<InventoryAdapter.InventoryViewHolder> {
+public class InventoryAdapter extends RecyclerView.Adapter<InventoryAdapter.InventoryViewHolder> implements BulkDeleteHandler.SelectableAdapter {
 
     private final List<InventoryDTO> inventoryList;
     private final OnInventoryClickListener clickListener;
-    private final List<Long> selectedIds = new ArrayList<>();
-    private boolean selectionMode = false;
+    private final SelectionHelper selectionHelper;
 
     public interface OnInventoryClickListener {
         void onInventoryClick(int position);
@@ -32,117 +30,97 @@ public class InventoryAdapter extends RecyclerView.Adapter<InventoryAdapter.Inve
     public InventoryAdapter(List<InventoryDTO> inventoryList, OnInventoryClickListener clickListener) {
         this.inventoryList = inventoryList;
         this.clickListener = clickListener;
+        this.selectionHelper = new SelectionHelper(new SelectionHelper.SelectionListener() {
+            @Override
+            public void onSelectionChanged(int count) {
+                clickListener.onSelectionChanged(count);
+            }
+
+            @Override
+            public void onSelectionModeToggle(boolean selectionMode) {
+                notifyDataSetChanged();
+            }
+        });
+    }
+
+    @Override
+    public List<String> getSelectedKeys() {
+        return selectionHelper.getSelectedKeys();
+    }
+
+    @Override
+    public void clearSelection() {
+        selectionHelper.clearSelection();
     }
 
     public static class InventoryViewHolder extends RecyclerView.ViewHolder {
-        // Matches desktop table columns: Inventory ID, Product ID, Product Name,
-        // Quantity
-        TextView tvInventoryId, tvProdId, tvProductName, tvQuantity;
-        CheckBox checkBox;
+        final ItemInventoryBinding binding;
 
-        public InventoryViewHolder(@NonNull View v) {
-            super(v);
-            tvInventoryId = v.findViewById(R.id.tvInventoryId);
-            tvProdId = v.findViewById(R.id.tvProdId);
-            tvProductName = v.findViewById(R.id.tvProductName);
-            tvQuantity = v.findViewById(R.id.tvQuantity);
-            checkBox = v.findViewById(R.id.cbSelectInventory);
+        public InventoryViewHolder(@NonNull ItemInventoryBinding binding) {
+            super(binding.getRoot());
+            this.binding = binding;
         }
     }
 
     @NonNull
     @Override
     public InventoryViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
-        View v = LayoutInflater.from(parent.getContext())
-                .inflate(R.layout.item_inventory, parent, false);
-        return new InventoryViewHolder(v);
+        ItemInventoryBinding binding = ItemInventoryBinding.inflate(LayoutInflater.from(parent.getContext()), parent, false);
+        return new InventoryViewHolder(binding);
     }
 
     @Override
     public void onBindViewHolder(@NonNull InventoryViewHolder holder, int position) {
         InventoryDTO inv = inventoryList.get(position);
-
-        // Column: Inventory ID
-        holder.tvInventoryId.setText(String.valueOf(inv.getInventoryId() != null ? inv.getInventoryId() : "—"));
-
-        // Column: Product ID
-        holder.tvProdId.setText(String.valueOf(inv.getProdId() != null ? inv.getProdId() : "—"));
+        ItemInventoryBinding binding = holder.binding;
 
         // Column: Product Name
-        holder.tvProductName.setText(inv.getProductName() != null ? inv.getProductName() : "—");
+        binding.tvProductName.setText(inv.getProductName() != null ? inv.getProductName() : "—");
+
+        // Column: Store Name
+        binding.tvInventoryStore.setText("Store: " + (inv.getStoreName() != null ? inv.getStoreName() : "—"));
 
         // Column: Quantity
         int qty = inv.getQuantity() != null ? inv.getQuantity() : 0;
-        holder.tvQuantity.setText(String.valueOf(qty));
+        binding.tvQuantity.setText("Stock: " + qty);
 
         // Low stock = red, normal = green (like desktop reorder concept)
         if (qty <= 5) {
-            holder.tvQuantity.setTextColor(Color.parseColor("#F44336"));
+            binding.tvQuantity.setTextColor(Color.parseColor("#F44336"));
         } else {
-            holder.tvQuantity.setTextColor(Color.parseColor("#4CAF50"));
+            binding.tvQuantity.setTextColor(Color.parseColor("#4CAF50"));
         }
 
+        String key = String.valueOf(inv.getInventoryId());
+
         // Bulk delete selection mode
-        if (selectionMode) {
-            holder.checkBox.setVisibility(View.VISIBLE);
-            holder.checkBox.setChecked(inv.getInventoryId() != null
-                    && selectedIds.contains(inv.getInventoryId()));
+        if (selectionHelper.isInSelectionMode()) {
+            binding.cbSelectInventory.setVisibility(View.VISIBLE);
+            binding.cbSelectInventory.setChecked(selectionHelper.isSelected(key));
         } else {
-            holder.checkBox.setVisibility(View.GONE);
-            holder.checkBox.setChecked(false);
+            binding.cbSelectInventory.setVisibility(View.GONE);
+            binding.cbSelectInventory.setChecked(false);
         }
 
         holder.itemView.setOnClickListener(v -> {
-            if (selectionMode) {
-                toggleSelection(inv.getInventoryId(), holder.checkBox);
+            if (selectionHelper.isInSelectionMode()) {
+                selectionHelper.toggleSelection(key);
+                notifyItemChanged(position);
             } else {
                 clickListener.onInventoryClick(holder.getAdapterPosition());
             }
         });
 
         holder.itemView.setOnLongClickListener(v -> {
-            if (!selectionMode) {
-                selectionMode = true;
-                toggleSelection(inv.getInventoryId(), holder.checkBox);
-                notifyDataSetChanged();
+            if (!selectionHelper.isInSelectionMode()) {
+                selectionHelper.startSelection(key);
             }
             return true;
         });
     }
 
-    private void toggleSelection(Long id, CheckBox checkBox) {
-        if (id == null)
-            return;
-        if (selectedIds.contains(id)) {
-            selectedIds.remove(id);
-            checkBox.setChecked(false);
-        } else {
-            selectedIds.add(id);
-            checkBox.setChecked(true);
-        }
-        clickListener.onSelectionChanged(selectedIds.size());
-        if (selectedIds.isEmpty()) {
-            selectionMode = false;
-            notifyDataSetChanged();
-        }
-    }
-
-    public List<Long> getSelectedIds() {
-        return new ArrayList<>(selectedIds);
-    }
-
-    public void clearSelection() {
-        selectedIds.clear();
-        selectionMode = false;
-        notifyDataSetChanged();
-    }
-
-    public boolean isInSelectionMode() {
-        return selectionMode;
-    }
-
     @Override
     public int getItemCount() {
         return inventoryList.size();
     }
-}
+}

android/app/src/main/java/com/example/petstoremobile/adapters/MessageAdapter.java

@@ -3,10 +3,17 @@ package com.example.petstoremobile.adapters;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
+import android.widget.ImageView;
 import android.widget.TextView;
 import androidx.annotation.NonNull;
 import androidx.recyclerview.widget.RecyclerView;
+import com.bumptech.glide.Glide;
+import com.bumptech.glide.load.engine.DiskCacheStrategy;
+import com.bumptech.glide.load.model.GlideUrl;
+import com.bumptech.glide.load.model.LazyHeaders;
 import com.example.petstoremobile.R;
+import com.example.petstoremobile.databinding.ItemMessageReceivedBinding;
+import com.example.petstoremobile.databinding.ItemMessageSentBinding;
 import com.example.petstoremobile.models.Message;
 import java.util.List;
 
@@ -17,6 +24,7 @@ public class MessageAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder
 
     private final List<Message> messages;
     private Long currentUserId;
+    private String token;
 
     public MessageAdapter(List<Message> messages, Long currentUserId) {
         this.messages = messages;
@@ -28,6 +36,10 @@ public class MessageAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder
         notifyDataSetChanged();
     }
 
+    public void setToken(String token) {
+        this.token = token;
+    }
+
     @Override
     public int getItemViewType(int position) {
         Message m = messages.get(position);
@@ -41,38 +53,75 @@ public class MessageAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder
     public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
         LayoutInflater inf = LayoutInflater.from(parent.getContext());
         if (viewType == TYPE_SENT) {
-            View v = inf.inflate(R.layout.item_message_sent, parent, false);
-            return new SentHolder(v);
+            ItemMessageSentBinding binding = ItemMessageSentBinding.inflate(inf, parent, false);
+            return new SentHolder(binding);
         } else {
-            View v = inf.inflate(R.layout.item_message_received, parent, false);
-            return new ReceivedHolder(v);
+            ItemMessageReceivedBinding binding = ItemMessageReceivedBinding.inflate(inf, parent, false);
+            return new ReceivedHolder(binding);
         }
     }
 
     @Override
     public void onBindViewHolder(@NonNull RecyclerView.ViewHolder holder, int position) {
         Message m = messages.get(position);
-        if (holder instanceof SentHolder)     ((SentHolder) holder).bind(m);
-        if (holder instanceof ReceivedHolder) ((ReceivedHolder) holder).bind(m);
+        if (holder instanceof SentHolder)     ((SentHolder) holder).bind(m, token);
+        if (holder instanceof ReceivedHolder) ((ReceivedHolder) holder).bind(m, token);
     }
 
     @Override public int getItemCount() { return messages.size(); }
 
     static class SentHolder extends RecyclerView.ViewHolder {
-        TextView tvMessage;
-        SentHolder(View v) {
-            super(v);
-            tvMessage = v.findViewById(R.id.tvMessageContent);  // updated
+        final ItemMessageSentBinding binding;
+        SentHolder(ItemMessageSentBinding binding) {
+            super(binding.getRoot());
+            this.binding = binding;
+        }
+        void bind(Message m, String token) {
+            binding.tvMessageContent.setText(m.getContent());
+            displayAttachment(m, binding.ivAttachment, binding.tvAttachmentName, token);
         }
-        void bind(Message m) { tvMessage.setText(m.getContent()); }
     }
 
     static class ReceivedHolder extends RecyclerView.ViewHolder {
-        TextView tvMessage;
-        ReceivedHolder(View v) {
-            super(v);
-            tvMessage = v.findViewById(R.id.tvMessageContent);  // updated
+        final ItemMessageReceivedBinding binding;
+        ReceivedHolder(ItemMessageReceivedBinding binding) {
+            super(binding.getRoot());
+            this.binding = binding;
+        }
+        void bind(Message m, String token) {
+            binding.tvMessageContent.setText(m.getContent());
+            displayAttachment(m, binding.ivAttachment, binding.tvAttachmentName, token);
+        }
+    }
+
+    // helper function to display the attachment to the chat bubble
+    private static void displayAttachment(Message m, ImageView iv, TextView tvName, String token) {
+        if (m.getAttachmentUrl() != null) {
+            if (m.getAttachmentType() != null && m.getAttachmentType().startsWith("image/")) {
+                iv.setVisibility(View.VISIBLE);
+                tvName.setVisibility(View.GONE);
+
+                Object loadTarget = m.getAttachmentUrl();
+                if (token != null && m.getAttachmentUrl().startsWith("http")) {
+                    loadTarget = new GlideUrl(m.getAttachmentUrl(), new LazyHeaders.Builder()
+                            .addHeader("Authorization", "Bearer " + token)
+                            .build());
+                }
+
+                Glide.with(iv.getContext())
+                        .load(loadTarget)
+                        .diskCacheStrategy(DiskCacheStrategy.ALL)
+                        .placeholder(R.drawable.placeholder)
+                        .error(R.drawable.placeholder)
+                        .into(iv);
+            } else {
+                iv.setVisibility(View.GONE);
+                tvName.setVisibility(View.VISIBLE);
+                tvName.setText(m.getAttachmentName() != null ? m.getAttachmentName() : "Attachment");
+            }
+        } else {
+            iv.setVisibility(View.GONE);
+            tvName.setVisibility(View.GONE);
         }
-        void bind(Message m) { tvMessage.setText(m.getContent()); }
     }
 }

android/app/src/main/java/com/example/petstoremobile/adapters/PetAdapter.java

@@ -4,40 +4,75 @@ import android.graphics.Color;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
-import android.widget.TextView;
 import androidx.annotation.NonNull;
 import androidx.recyclerview.widget.RecyclerView;
+
 import com.example.petstoremobile.R;
+import com.example.petstoremobile.api.PetApi;
+import com.example.petstoremobile.databinding.ItemPetBinding;
 import com.example.petstoremobile.dtos.PetDTO;
+import com.example.petstoremobile.utils.BulkDeleteHandler;
+import com.example.petstoremobile.utils.GlideUtils;
+import com.example.petstoremobile.utils.SelectionHelper;
+
 import java.util.List;
 
-public class PetAdapter extends RecyclerView.Adapter<PetAdapter.PetViewHolder> {
+public class PetAdapter extends RecyclerView.Adapter<PetAdapter.PetViewHolder> implements BulkDeleteHandler.SelectableAdapter {
 
     private List<PetDTO> petList;
     private OnPetClickListener petClickListener;
+    private String baseUrl;
+    private String token;
+    private final SelectionHelper selectionHelper;
 
     // Interface for pet click on recycler view
     public interface OnPetClickListener {
         void onPetClick(int position);
+        void onSelectionChanged(int selectedCount);
     }
 
     //Constructor
     public PetAdapter(List<PetDTO> petList, OnPetClickListener petClickListener) {
         this.petList  = petList;
         this.petClickListener = petClickListener;
+        this.selectionHelper = new SelectionHelper(new SelectionHelper.SelectionListener() {
+            @Override
+            public void onSelectionChanged(int count) {
+                petClickListener.onSelectionChanged(count);
+            }
+
+            @Override
+            public void onSelectionModeToggle(boolean selectionMode) {
+                notifyDataSetChanged();
+            }
+        });
+    }
+
+    public void setBaseUrl(String baseUrl) {
+        this.baseUrl = baseUrl;
+    }
+
+    public void setToken(String token) {
+        this.token = token;
+    }
+
+    @Override
+    public List<String> getSelectedKeys() {
+        return selectionHelper.getSelectedKeys();
+    }
+
+    @Override
+    public void clearSelection() {
+        selectionHelper.clearSelection();
     }
 
     // Get the controls of each row in recycler view
     public static class PetViewHolder extends RecyclerView.ViewHolder {
-        TextView tvPetName, tvPetSpeciesBreed, tvPetAge, tvPetPrice, tvPetStatus;
+        private final ItemPetBinding binding;
 
-        public PetViewHolder(@NonNull View v) {
-            super(v);
-            tvPetName = v.findViewById(R.id.tvPetName);
-            tvPetSpeciesBreed = v.findViewById(R.id.tvPetSpeciesBreed);
-            tvPetAge = v.findViewById(R.id.tvPetAge);
-            tvPetPrice = v.findViewById(R.id.tvPetPrice);
-            tvPetStatus = v.findViewById(R.id.tvPetStatus);
+        public PetViewHolder(@NonNull ItemPetBinding binding) {
+            super(binding.getRoot());
+            this.binding = binding;
         }
     }
 
@@ -45,41 +80,75 @@ public class PetAdapter extends RecyclerView.Adapter<PetAdapter.PetViewHolder> {
     @NonNull
     @Override
     public PetViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
-        View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_pet, parent, false);
-        return new PetViewHolder(v);
+        ItemPetBinding binding = ItemPetBinding.inflate(LayoutInflater.from(parent.getContext()), parent, false);
+        return new PetViewHolder(binding);
     }
 
     //populate the row with pet data
     @Override
     public void onBindViewHolder(@NonNull PetViewHolder holder, int position) {
         PetDTO pet = petList.get(position);
+        ItemPetBinding binding = holder.binding;
 
-        holder.tvPetName.setText(pet.getPetName());
-        holder.tvPetSpeciesBreed.setText(pet.getPetSpecies() + " - " + pet.getPetBreed());
-        holder.tvPetAge.setText("Age: " + pet.getPetAge() + " yr(s)");
+        binding.tvPetName.setText(pet.getPetName());
+        binding.tvPetSpeciesBreed.setText(pet.getPetSpecies() + " - " + pet.getPetBreed());
+        binding.tvPetAge.setText("Age: " + pet.getPetAge() + " yr(s)");
         
-        try {
-            double price = Double.parseDouble(pet.getPetPrice());
-            holder.tvPetPrice.setText("$" + String.format("%.2f", price));
-        } catch (Exception e) {
-            holder.tvPetPrice.setText("$" + pet.getPetPrice());
+        Double price = pet.getPetPrice();
+        if (price != null) {
+            binding.tvPetPrice.setText("$" + String.format("%.2f", price));
+        } else {
+            binding.tvPetPrice.setText("$0.00");
         }
         
-        holder.tvPetStatus.setText(pet.getPetStatus());
+        binding.tvPetStatus.setText(pet.getPetStatus());
 
         //Set the status color depending on availability. If available, green, otherwise red
         if (pet.getPetStatus() != null && pet.getPetStatus().equals("Available")) {
-            holder.tvPetStatus.setBackgroundColor(Color.parseColor("#4CAF50"));
+            binding.tvPetStatus.setBackgroundColor(Color.parseColor("#4CAF50"));
         } else {
-            holder.tvPetStatus.setBackgroundColor(Color.parseColor("#F44336"));
+            binding.tvPetStatus.setBackgroundColor(Color.parseColor("#F44336"));
+        }
+
+        // Load pet image using Glide
+        if (baseUrl != null) {
+            String imageUrl = baseUrl + String.format(PetApi.PET_IMAGE_PATH, pet.getPetId());
+            GlideUtils.loadImageWithTokenCircle(holder.itemView.getContext(), binding.ivPetProfile, imageUrl, token, R.drawable.placeholder);
+        } else {
+            binding.ivPetProfile.setImageResource(R.drawable.placeholder);
+        }
+
+        String key = String.valueOf(pet.getPetId());
+
+        // Bulk delete selection mode
+        if (selectionHelper.isInSelectionMode()) {
+            binding.cbSelectPet.setVisibility(View.VISIBLE);
+            binding.cbSelectPet.setChecked(selectionHelper.isSelected(key));
+        } else {
+            binding.cbSelectPet.setVisibility(View.GONE);
+            binding.cbSelectPet.setChecked(false);
         }
 
         //when a row is clicked, open the detail view
-        holder.itemView.setOnClickListener(v -> petClickListener.onPetClick(position));
+        holder.itemView.setOnClickListener(v -> {
+            if (selectionHelper.isInSelectionMode()) {
+                selectionHelper.toggleSelection(key);
+                notifyItemChanged(position);
+            } else {
+                petClickListener.onPetClick(position);
+            }
+        });
+
+        holder.itemView.setOnLongClickListener(v -> {
+            if (!selectionHelper.isInSelectionMode()) {
+                selectionHelper.startSelection(key);
+            }
+            return true;
+        });
     }
 
     @Override
     public int getItemCount() {
         return petList.size();
     }
-}
+}

android/app/src/main/java/com/example/petstoremobile/adapters/ProductAdapter.java

@@ -1,17 +1,22 @@
 package com.example.petstoremobile.adapters;
 
 import android.view.*;
-import android.widget.TextView;
 import androidx.annotation.NonNull;
 import androidx.recyclerview.widget.RecyclerView;
+
 import com.example.petstoremobile.R;
+import com.example.petstoremobile.api.ProductApi;
+import com.example.petstoremobile.databinding.ItemProductBinding;
 import com.example.petstoremobile.dtos.ProductDTO;
+import com.example.petstoremobile.utils.GlideUtils;
 import java.util.List;
 
 public class ProductAdapter extends RecyclerView.Adapter<ProductAdapter.ProductViewHolder> {
 
     private List<ProductDTO> productList;
     private OnProductClickListener listener;
+    private String baseUrl;
+    private String token;
 
     public interface OnProductClickListener {
         void onProductClick(int position);
@@ -22,33 +27,48 @@ public class ProductAdapter extends RecyclerView.Adapter<ProductAdapter.ProductV
         this.listener = listener;
     }
 
-    public static class ProductViewHolder extends RecyclerView.ViewHolder {
-        TextView tvName, tvCategory, tvDesc, tvPrice;
+    public void setBaseUrl(String baseUrl) {
+        this.baseUrl = baseUrl;
+    }
 
-        public ProductViewHolder(@NonNull View v) {
-            super(v);
-            tvName     = v.findViewById(R.id.tvProductName);
-            tvCategory = v.findViewById(R.id.tvProductCategory);
-            tvDesc     = v.findViewById(R.id.tvProductDesc);
-            tvPrice    = v.findViewById(R.id.tvProductPrice);
+    public void setToken(String token) {
+        this.token = token;
+    }
+
+    public static class ProductViewHolder extends RecyclerView.ViewHolder {
+        final ItemProductBinding binding;
+
+        public ProductViewHolder(@NonNull ItemProductBinding binding) {
+            super(binding.getRoot());
+            this.binding = binding;
         }
     }
 
     @NonNull
     @Override
     public ProductViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
-        View v = LayoutInflater.from(parent.getContext())
-                .inflate(R.layout.item_product, parent, false);
-        return new ProductViewHolder(v);
+        ItemProductBinding binding = ItemProductBinding.inflate(LayoutInflater.from(parent.getContext()), parent, false);
+        return new ProductViewHolder(binding);
     }
 
     @Override
     public void onBindViewHolder(@NonNull ProductViewHolder holder, int position) {
         ProductDTO p = productList.get(position);
-        holder.tvName.setText(p.getProdName() != null ? p.getProdName() : "");
-        holder.tvCategory.setText("Category: " + (p.getCategoryName() != null ? p.getCategoryName() : ""));
-        holder.tvDesc.setText(p.getProdDesc() != null ? p.getProdDesc() : "");
-        holder.tvPrice.setText(p.getProdPrice() != null ? "$" + p.getProdPrice() : "");
+        ItemProductBinding binding = holder.binding;
+
+        binding.tvProductName.setText(p.getProdName() != null ? p.getProdName() : "");
+        binding.tvProductCategory.setText("Category: " + (p.getCategoryName() != null ? p.getCategoryName() : ""));
+        binding.tvProductDesc.setText(p.getProdDesc() != null ? p.getProdDesc() : "");
+        binding.tvProductPrice.setText(p.getProdPrice() != null ? "$" + p.getProdPrice() : "");
+
+        // Load product image using Glide
+        if (baseUrl != null) {
+            String imageUrl = baseUrl + String.format(ProductApi.PRODUCT_IMAGE_PATH, p.getProdId());
+            GlideUtils.loadImageWithTokenCircle(holder.itemView.getContext(), binding.ivProductImage, imageUrl, token, R.drawable.placeholder);
+        } else {
+            binding.ivProductImage.setImageResource(R.drawable.placeholder);
+        }
+
         holder.itemView.setOnClickListener(v -> listener.onProductClick(position));
     }
 

android/app/src/main/java/com/example/petstoremobile/adapters/ProductSupplierAdapter.java

@@ -1,55 +1,109 @@
 package com.example.petstoremobile.adapters;
 
-import android.view.*;
-import android.widget.TextView;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+
 import androidx.annotation.NonNull;
 import androidx.recyclerview.widget.RecyclerView;
-import com.example.petstoremobile.R;
+
+import com.example.petstoremobile.databinding.ItemProductSupplierBinding;
 import com.example.petstoremobile.dtos.ProductSupplierDTO;
+import com.example.petstoremobile.utils.BulkDeleteHandler;
+import com.example.petstoremobile.utils.SelectionHelper;
+
 import java.util.List;
 
-public class ProductSupplierAdapter extends RecyclerView.Adapter<ProductSupplierAdapter.PSViewHolder> {
+public class ProductSupplierAdapter extends RecyclerView.Adapter<ProductSupplierAdapter.PSViewHolder> implements BulkDeleteHandler.SelectableAdapter {
 
-    private List<ProductSupplierDTO> list;
-    private OnProductSupplierClickListener listener;
+    private final List<ProductSupplierDTO> list;
+    private final OnProductSupplierClickListener listener;
+    private final SelectionHelper selectionHelper;
 
     public interface OnProductSupplierClickListener {
         void onProductSupplierClick(int position);
+        void onSelectionChanged(int count);
     }
 
     public ProductSupplierAdapter(List<ProductSupplierDTO> list, OnProductSupplierClickListener listener) {
         this.list = list;
         this.listener = listener;
+        this.selectionHelper = new SelectionHelper(new SelectionHelper.SelectionListener() {
+            @Override
+            public void onSelectionChanged(int count) {
+                listener.onSelectionChanged(count);
+            }
+
+            @Override
+            public void onSelectionModeToggle(boolean selectionMode) {
+                notifyDataSetChanged();
+            }
+        });
+    }
+
+    @Override
+    public List<String> getSelectedKeys() {
+        return selectionHelper.getSelectedKeys();
+    }
+
+    @Override
+    public void clearSelection() {
+        selectionHelper.clearSelection();
     }
 
     public static class PSViewHolder extends RecyclerView.ViewHolder {
-        TextView tvProductName, tvSupplierName, tvCost;
+        final ItemProductSupplierBinding binding;
 
-        public PSViewHolder(@NonNull View v) {
-            super(v);
-            tvProductName  = v.findViewById(R.id.tvPSProductName);
-            tvSupplierName = v.findViewById(R.id.tvPSSupplierName);
-            tvCost         = v.findViewById(R.id.tvPSCost);
+        public PSViewHolder(@NonNull ItemProductSupplierBinding binding) {
+            super(binding.getRoot());
+            this.binding = binding;
         }
     }
 
     @NonNull
     @Override
     public PSViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
-        View v = LayoutInflater.from(parent.getContext())
-                .inflate(R.layout.item_product_supplier, parent, false);
-        return new PSViewHolder(v);
+        ItemProductSupplierBinding binding = ItemProductSupplierBinding.inflate(LayoutInflater.from(parent.getContext()), parent, false);
+        return new PSViewHolder(binding);
     }
 
     @Override
     public void onBindViewHolder(@NonNull PSViewHolder holder, int position) {
         ProductSupplierDTO ps = list.get(position);
-        holder.tvProductName.setText(ps.getProductName() != null ? ps.getProductName() : "");
-        holder.tvSupplierName.setText("Supplier: " + (ps.getSupplierName() != null ? ps.getSupplierName() : ""));
-        holder.tvCost.setText(ps.getCost() != null ? "Cost: $" + ps.getCost() : "");
-        holder.itemView.setOnClickListener(v -> listener.onProductSupplierClick(position));
+        ItemProductSupplierBinding binding = holder.binding;
+
+        binding.tvPSProductName.setText(ps.getProductName() != null ? ps.getProductName() : "");
+        binding.tvPSSupplierName.setText("Supplier: " + (ps.getSupplierName() != null ? ps.getSupplierName() : ""));
+        binding.tvPSCost.setText(ps.getCost() != null ? "Cost: $" + ps.getCost() : "");
+
+        String key = ps.getProductId() + "-" + ps.getSupplierId();
+
+        // Bulk delete selection mode
+        if (selectionHelper.isInSelectionMode()) {
+            binding.cbSelectProductSupplier.setVisibility(View.VISIBLE);
+            binding.cbSelectProductSupplier.setChecked(selectionHelper.isSelected(key));
+        } else {
+            binding.cbSelectProductSupplier.setVisibility(View.GONE);
+            binding.cbSelectProductSupplier.setChecked(false);
+        }
+
+        holder.itemView.setOnClickListener(v -> {
+            if (selectionHelper.isInSelectionMode()) {
+                selectionHelper.toggleSelection(key);
+                notifyItemChanged(position);
+            } else {
+                listener.onProductSupplierClick(position);
+            }
+        });
+
+        holder.itemView.setOnLongClickListener(v -> {
+            if (!selectionHelper.isInSelectionMode()) {
+                selectionHelper.startSelection(key);
+            }
+            return true;
+        });
     }
 
     @Override
     public int getItemCount() { return list.size(); }
-}
+}

android/app/src/main/java/com/example/petstoremobile/adapters/PurchaseOrderAdapter.java

@@ -1,11 +1,11 @@
 package com.example.petstoremobile.adapters;
 
 import android.graphics.Color;
-import android.view.*;
-import android.widget.TextView;
+import android.view.LayoutInflater;
+import android.view.ViewGroup;
 import androidx.annotation.NonNull;
 import androidx.recyclerview.widget.RecyclerView;
-import com.example.petstoremobile.R;
+import com.example.petstoremobile.databinding.ItemPurchaseOrderBinding;
 import com.example.petstoremobile.dtos.PurchaseOrderDTO;
 import java.util.List;
 
@@ -24,47 +24,49 @@ public class PurchaseOrderAdapter extends RecyclerView.Adapter<PurchaseOrderAdap
     }
 
     public static class POViewHolder extends RecyclerView.ViewHolder {
-        TextView tvId, tvSupplier, tvDate, tvStatus;
+        final ItemPurchaseOrderBinding binding;
 
-        public POViewHolder(@NonNull View v) {
-            super(v);
-            tvId = v.findViewById(R.id.tvPOId);
-            tvSupplier = v.findViewById(R.id.tvPOSupplier);
-            tvDate = v.findViewById(R.id.tvPODate);
-            tvStatus = v.findViewById(R.id.tvPOStatus);
+        public POViewHolder(@NonNull ItemPurchaseOrderBinding binding) {
+            super(binding.getRoot());
+            this.binding = binding;
         }
     }
 
     @NonNull
     @Override
     public POViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
-        View v = LayoutInflater.from(parent.getContext())
-                .inflate(R.layout.item_purchase_order, parent, false);
-        return new POViewHolder(v);
+        ItemPurchaseOrderBinding binding = ItemPurchaseOrderBinding.inflate(LayoutInflater.from(parent.getContext()), parent, false);
+        return new POViewHolder(binding);
     }
 
     @Override
     public void onBindViewHolder(@NonNull POViewHolder holder, int position) {
         PurchaseOrderDTO po = list.get(position);
-        holder.tvId.setText("PO #" + (po.getPurchaseOrderId() != null ? po.getPurchaseOrderId() : ""));
-        holder.tvSupplier.setText("Supplier: " + (po.getSupplierName() != null ? po.getSupplierName() : ""));
-        holder.tvDate.setText("Date: " + (po.getOrderDate() != null ? po.getOrderDate() : ""));
+        ItemPurchaseOrderBinding binding = holder.binding;
+
+        binding.tvPOId.setText("PO #" + (po.getPurchaseOrderId() != null ? po.getPurchaseOrderId() : ""));
+        binding.tvPOSupplier.setText("Supplier: " + (po.getSupplierName() != null ? po.getSupplierName() : ""));
+        binding.tvPOStore.setText("Store: " + (po.getStoreName() != null ? po.getStoreName() : ""));
+        binding.tvPODate.setText("Date: " + (po.getOrderDate() != null ? po.getOrderDate() : ""));
 
         String status = po.getStatus() != null ? po.getStatus() : "";
-        holder.tvStatus.setText(status);
+        binding.tvPOStatus.setText(status);
 
-        switch (status) {
-            case "Completed":
-                holder.tvStatus.setBackgroundColor(Color.parseColor("#4CAF50"));
+        switch (status.toUpperCase()) {
+            case "RECEIVED":
+                binding.tvPOStatus.setBackgroundColor(Color.parseColor("#4CAF50"));
                 break;
-            case "Pending":
-                holder.tvStatus.setBackgroundColor(Color.parseColor("#FF9800"));
+            case "PLACED":
+                binding.tvPOStatus.setBackgroundColor(Color.parseColor("#2196F3"));
                 break;
-            case "Cancelled":
-                holder.tvStatus.setBackgroundColor(Color.parseColor("#F44336"));
+            case "PENDING":
+                binding.tvPOStatus.setBackgroundColor(Color.parseColor("#FF9800"));
+                break;
+            case "CANCELLED":
+                binding.tvPOStatus.setBackgroundColor(Color.parseColor("#F44336"));
                 break;
             default:
-                holder.tvStatus.setBackgroundColor(Color.parseColor("#9E9E9E"));
+                binding.tvPOStatus.setBackgroundColor(Color.parseColor("#9E9E9E"));
                 break;
         }
 

android/app/src/main/java/com/example/petstoremobile/adapters/SaleAdapter.java

@@ -1,10 +1,12 @@
 package com.example.petstoremobile.adapters;
 
-import android.view.*;
-import android.widget.TextView;
+import android.graphics.Color;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
 import androidx.annotation.NonNull;
 import androidx.recyclerview.widget.RecyclerView;
-import com.example.petstoremobile.R;
+import com.example.petstoremobile.databinding.ItemSaleBinding;
 import com.example.petstoremobile.dtos.SaleDTO;
 import java.util.List;
 
@@ -23,41 +25,39 @@ public class SaleAdapter extends RecyclerView.Adapter<SaleAdapter.SaleViewHolder
     }
 
     public static class SaleViewHolder extends RecyclerView.ViewHolder {
-        TextView tvId, tvEmployee, tvDate, tvPayment, tvTotal, tvRefundBadge;
+        final ItemSaleBinding binding;
 
-        public SaleViewHolder(@NonNull View v) {
-            super(v);
-            tvId = v.findViewById(R.id.tvSaleId);
-            tvEmployee = v.findViewById(R.id.tvSaleEmployee);
-            tvDate = v.findViewById(R.id.tvSaleDate);
-            tvPayment = v.findViewById(R.id.tvSalePayment);
-            tvTotal = v.findViewById(R.id.tvSaleTotal);
-            tvRefundBadge = v.findViewById(R.id.tvSaleRefundBadge);
+        public SaleViewHolder(@NonNull ItemSaleBinding binding) {
+            super(binding.getRoot());
+            this.binding = binding;
         }
     }
 
     @NonNull
     @Override
     public SaleViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
-        View v = LayoutInflater.from(parent.getContext())
-                .inflate(R.layout.item_sale, parent, false);
-        return new SaleViewHolder(v);
+        ItemSaleBinding binding = ItemSaleBinding.inflate(LayoutInflater.from(parent.getContext()), parent, false);
+        return new SaleViewHolder(binding);
     }
 
     @Override
     public void onBindViewHolder(@NonNull SaleViewHolder holder, int position) {
         SaleDTO s = saleList.get(position);
-        holder.tvId.setText("Sale #" + (s.getSaleId() != null ? s.getSaleId() : ""));
-        holder.tvEmployee.setText("By: " + (s.getEmployeeName() != null ? s.getEmployeeName() : ""));
-        holder.tvDate.setText(s.getSaleDate() != null ? s.getSaleDate().substring(0, 10) : "");
-        holder.tvPayment.setText(s.getPaymentMethod() != null ? s.getPaymentMethod() : "");
-        holder.tvTotal.setText(s.getTotalAmount() != null ? "$" + s.getTotalAmount() : "");
+        ItemSaleBinding binding = holder.binding;
+
+        binding.tvSaleId.setText("Sale #" + (s.getSaleId() != null ? s.getSaleId() : ""));
+        binding.tvSaleEmployee.setText("By: " + (s.getEmployeeName() != null ? s.getEmployeeName() : ""));
+        binding.tvSaleDate.setText(s.getSaleDate() != null ? s.getSaleDate().substring(0, Math.min(10, s.getSaleDate().length())) : "");
+        binding.tvSalePayment.setText(s.getPaymentMethod() != null ? s.getPaymentMethod() : "");
+        binding.tvSaleTotal.setText(s.getTotalAmount() != null ? "$" + s.getTotalAmount() : "");
 
-        // Show refund badge
         if (Boolean.TRUE.equals(s.getIsRefund())) {
-            holder.tvRefundBadge.setVisibility(View.VISIBLE);
+            binding.tvSaleRefundBadge.setVisibility(View.VISIBLE);
+            binding.tvSaleRefundBadge.setBackgroundColor(Color.parseColor("#F44336"));
+            binding.tvSaleTotal.setTextColor(Color.parseColor("#F44336"));
         } else {
-            holder.tvRefundBadge.setVisibility(View.GONE);
+            binding.tvSaleRefundBadge.setVisibility(View.GONE);
+            binding.tvSaleTotal.setTextColor(Color.parseColor("#4CAF50"));
         }
 
         holder.itemView.setOnClickListener(v -> listener.onSaleClick(position));
@@ -67,4 +67,4 @@ public class SaleAdapter extends RecyclerView.Adapter<SaleAdapter.SaleViewHolder
     public int getItemCount() {
         return saleList.size();
     }
-}
+}

android/app/src/main/java/com/example/petstoremobile/adapters/ServiceAdapter.java

@@ -3,39 +3,69 @@ package com.example.petstoremobile.adapters;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
-import android.widget.TextView;
+
 import androidx.annotation.NonNull;
 import androidx.recyclerview.widget.RecyclerView;
-import com.example.petstoremobile.R;
+
+import com.example.petstoremobile.databinding.ItemServiceBinding;
 import com.example.petstoremobile.dtos.ServiceDTO;
+import com.example.petstoremobile.utils.BulkDeleteHandler;
+import com.example.petstoremobile.utils.SelectionHelper;
+
 import java.util.List;
 
-public class ServiceAdapter extends RecyclerView.Adapter<ServiceAdapter.ServiceViewHolder> {
+/**
+ * Adapter class for displaying a list of services in a RecyclerView.
+ */
+public class ServiceAdapter extends RecyclerView.Adapter<ServiceAdapter.ServiceViewHolder> implements BulkDeleteHandler.SelectableAdapter {
 
-    private List<ServiceDTO> serviceList;
-    private OnServiceClickListener serviceClickListener;
+    private final List<ServiceDTO> serviceList;
+    private final OnServiceClickListener clickListener;
+    private final SelectionHelper selectionHelper;
 
-    // Interface for service click on recycler view
+    /**
+     * Interface for handling clicks on service items.
+     */
     public interface OnServiceClickListener {
         void onServiceClick(int position);
+        void onSelectionChanged(int count);
     }
 
-    //Constructor
-    public ServiceAdapter(List<ServiceDTO> serviceList, OnServiceClickListener serviceClickListener) {
-        this.serviceList  = serviceList;
-        this.serviceClickListener = serviceClickListener;
+    public ServiceAdapter(List<ServiceDTO> serviceList, OnServiceClickListener clickListener) {
+        this.serviceList = serviceList;
+        this.clickListener = clickListener;
+        this.selectionHelper = new SelectionHelper(new SelectionHelper.SelectionListener() {
+            @Override
+            public void onSelectionChanged(int count) {
+                clickListener.onSelectionChanged(count);
+            }
+
+            @Override
+            public void onSelectionModeToggle(boolean selectionMode) {
+                notifyDataSetChanged();
+            }
+        });
     }
 
-    // Get the controls of each row in recycler view
+    @Override
+    public List<String> getSelectedKeys() {
+        return selectionHelper.getSelectedKeys();
+    }
+
+    @Override
+    public void clearSelection() {
+        selectionHelper.clearSelection();
+    }
+
+    /**
+     * ViewHolder class for service items.
+     */
     public static class ServiceViewHolder extends RecyclerView.ViewHolder {
-        TextView tvServiceName, tvServiceDesc, tvServiceDuration, tvServicePrice;
+        final ItemServiceBinding binding;
 
-        public ServiceViewHolder(@NonNull View v) {
-            super(v);
-            tvServiceName = v.findViewById(R.id.tvServiceName);
-            tvServiceDesc = v.findViewById(R.id.tvServiceDesc);
-            tvServiceDuration = v.findViewById(R.id.tvServiceDuration);
-            tvServicePrice = v.findViewById(R.id.tvServicePrice);
+        public ServiceViewHolder(@NonNull ItemServiceBinding binding) {
+            super(binding.getRoot());
+            this.binding = binding;
         }
     }
 
@@ -43,26 +73,51 @@ public class ServiceAdapter extends RecyclerView.Adapter<ServiceAdapter.ServiceV
     @NonNull
     @Override
     public ServiceViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
-        View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_service, parent, false);
-        return new ServiceViewHolder(v);
+        ItemServiceBinding binding = ItemServiceBinding.inflate(LayoutInflater.from(parent.getContext()), parent, false);
+        return new ServiceViewHolder(binding);
     }
 
     //populate the row with service data
     @Override
     public void onBindViewHolder(@NonNull ServiceViewHolder holder, int position) {
         ServiceDTO service = serviceList.get(position);
+        ItemServiceBinding binding = holder.binding;
 
-        holder.tvServiceName.setText(service.getServiceName());
-        holder.tvServiceDesc.setText(service.getServiceDesc());
-        holder.tvServiceDuration.setText("Duration: " + service.getServiceDuration() + " min");
-        holder.tvServicePrice.setText("$" + String.format("%.2f", service.getServicePrice()));
+        binding.tvServiceName.setText(service.getServiceName());
+        binding.tvServiceDesc.setText(service.getServiceDesc());
+        binding.tvServiceDuration.setText(service.getServiceDuration() != null ? service.getServiceDuration() + " mins" : "0 mins");
+        binding.tvServicePrice.setText(service.getServicePrice() != null ? "$" + String.format("%.2f", service.getServicePrice()) : "$0.00");
 
-        //when a row is clicked, open the detail view
-        holder.itemView.setOnClickListener(v -> serviceClickListener.onServiceClick(position));
+        String key = String.valueOf(service.getServiceId());
+
+        // Bulk delete selection mode
+        if (selectionHelper.isInSelectionMode()) {
+            binding.cbSelectService.setVisibility(View.VISIBLE);
+            binding.cbSelectService.setChecked(selectionHelper.isSelected(key));
+        } else {
+            binding.cbSelectService.setVisibility(View.GONE);
+            binding.cbSelectService.setChecked(false);
+        }
+
+        holder.itemView.setOnClickListener(v -> {
+            if (selectionHelper.isInSelectionMode()) {
+                selectionHelper.toggleSelection(key);
+                notifyItemChanged(position);
+            } else {
+                clickListener.onServiceClick(position);
+            }
+        });
+
+        holder.itemView.setOnLongClickListener(v -> {
+            if (!selectionHelper.isInSelectionMode()) {
+                selectionHelper.startSelection(key);
+            }
+            return true;
+        });
     }
 
     @Override
     public int getItemCount() {
         return serviceList.size();
     }
-}
+}

android/app/src/main/java/com/example/petstoremobile/adapters/SupplierAdapter.java

@@ -3,39 +3,63 @@ package com.example.petstoremobile.adapters;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
-import android.widget.TextView;
+
 import androidx.annotation.NonNull;
 import androidx.recyclerview.widget.RecyclerView;
-import com.example.petstoremobile.R;
+
+import com.example.petstoremobile.databinding.ItemSupplierBinding;
 import com.example.petstoremobile.dtos.SupplierDTO;
+import com.example.petstoremobile.utils.BulkDeleteHandler;
+import com.example.petstoremobile.utils.SelectionHelper;
+
 import java.util.List;
 
-public class SupplierAdapter extends RecyclerView.Adapter<SupplierAdapter.SupplierViewHolder> {
+public class SupplierAdapter extends RecyclerView.Adapter<SupplierAdapter.SupplierViewHolder> implements BulkDeleteHandler.SelectableAdapter {
 
-    private List<SupplierDTO> supplierList;
-    private OnSupplierClickListener supplierClickListener;
+    private final List<SupplierDTO> supplierList;
+    private final OnSupplierClickListener supplierClickListener;
+    private final SelectionHelper selectionHelper;
 
     // Interface for supplier click on recycler view
     public interface OnSupplierClickListener {
         void onSupplierClick(int position);
+        void onSelectionChanged(int count);
     }
 
     //Constructor
     public SupplierAdapter(List<SupplierDTO> supplierList, OnSupplierClickListener supplierClickListener) {
         this.supplierList  = supplierList;
         this.supplierClickListener = supplierClickListener;
+        this.selectionHelper = new SelectionHelper(new SelectionHelper.SelectionListener() {
+            @Override
+            public void onSelectionChanged(int count) {
+                supplierClickListener.onSelectionChanged(count);
+            }
+
+            @Override
+            public void onSelectionModeToggle(boolean selectionMode) {
+                notifyDataSetChanged();
+            }
+        });
+    }
+
+    @Override
+    public List<String> getSelectedKeys() {
+        return selectionHelper.getSelectedKeys();
+    }
+
+    @Override
+    public void clearSelection() {
+        selectionHelper.clearSelection();
     }
 
     // Get the controls of each row in recycler view
     public static class SupplierViewHolder extends RecyclerView.ViewHolder {
-        TextView tvSupCompany, tvSupContactName, tvSupEmail, tvSupPhone;
+        final ItemSupplierBinding binding;
 
-        public SupplierViewHolder(@NonNull View v) {
-            super(v);
-            tvSupCompany = v.findViewById(R.id.tvSupCompany);
-            tvSupContactName = v.findViewById(R.id.tvSupContactName);
-            tvSupEmail = v.findViewById(R.id.tvSupEmail);
-            tvSupPhone = v.findViewById(R.id.tvSupPhone);
+        public SupplierViewHolder(@NonNull ItemSupplierBinding binding) {
+            super(binding.getRoot());
+            this.binding = binding;
         }
     }
 
@@ -43,26 +67,52 @@ public class SupplierAdapter extends RecyclerView.Adapter<SupplierAdapter.Suppli
     @NonNull
     @Override
     public SupplierViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
-        View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_supplier, parent, false);
-        return new SupplierViewHolder(v);
+        ItemSupplierBinding binding = ItemSupplierBinding.inflate(LayoutInflater.from(parent.getContext()), parent, false);
+        return new SupplierViewHolder(binding);
     }
 
     //populate the row with supplier data
     @Override
     public void onBindViewHolder(@NonNull SupplierViewHolder holder, int position) {
         SupplierDTO supplier = supplierList.get(position);
+        ItemSupplierBinding binding = holder.binding;
 
-        holder.tvSupCompany.setText(supplier.getSupCompany());
-        holder.tvSupContactName.setText(supplier.getSupContactFirstName() + " " + supplier.getSupContactLastName());
-        holder.tvSupEmail.setText(supplier.getSupEmail());
-        holder.tvSupPhone.setText(supplier.getSupPhone());
+        binding.tvSupCompany.setText(supplier.getSupCompany());
+        binding.tvSupContactName.setText(supplier.getSupContactFirstName() + " " + supplier.getSupContactLastName());
+        binding.tvSupEmail.setText(supplier.getSupEmail());
+        binding.tvSupPhone.setText(supplier.getSupPhone());
+
+        String key = String.valueOf(supplier.getSupId());
+
+        // Bulk delete selection mode
+        if (selectionHelper.isInSelectionMode()) {
+            binding.cbSelectSupplier.setVisibility(View.VISIBLE);
+            binding.cbSelectSupplier.setChecked(selectionHelper.isSelected(key));
+        } else {
+            binding.cbSelectSupplier.setVisibility(View.GONE);
+            binding.cbSelectSupplier.setChecked(false);
+        }
 
         //when a row is clicked, open the detail view
-        holder.itemView.setOnClickListener(v -> supplierClickListener.onSupplierClick(position));
+        holder.itemView.setOnClickListener(v -> {
+            if (selectionHelper.isInSelectionMode()) {
+                selectionHelper.toggleSelection(key);
+                notifyItemChanged(position);
+            } else {
+                supplierClickListener.onSupplierClick(position);
+            }
+        });
+
+        holder.itemView.setOnLongClickListener(v -> {
+            if (!selectionHelper.isInSelectionMode()) {
+                selectionHelper.startSelection(key);
+            }
+            return true;
+        });
     }
 
     @Override
     public int getItemCount() {
         return supplierList.size();
     }
-}
+}

android/app/src/main/java/com/example/petstoremobile/adapters/WhiteTextArrayAdapter.java

@@ -0,0 +1,47 @@
+package com.example.petstoremobile.adapters;
+
+import android.content.Context;
+import android.graphics.Color;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.ArrayAdapter;
+import android.widget.TextView;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.core.content.ContextCompat;
+import com.example.petstoremobile.R;
+import java.util.List;
+
+/**
+ * A class that overrides the arrayAdapter so the text color is white and background is transparent.
+ */
+public class WhiteTextArrayAdapter<T> extends ArrayAdapter<T> {
+    public WhiteTextArrayAdapter(@NonNull Context context, int resource, @NonNull T[] objects) {
+        super(context, resource, objects);
+    }
+
+    public WhiteTextArrayAdapter(@NonNull Context context, int resource, @NonNull List<T> objects) {
+        super(context, resource, objects);
+    }
+
+    @NonNull
+    @Override
+    public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {
+        View view = super.getView(position, convertView, parent);
+        view.setBackgroundColor(Color.TRANSPARENT);
+        if (view instanceof TextView) {
+            ((TextView) view).setTextColor(Color.WHITE);
+        }
+        return view;
+    }
+    
+    @Override
+    public View getDropDownView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {
+        View view = super.getDropDownView(position, convertView, parent);
+        view.setBackgroundColor(ContextCompat.getColor(getContext(), R.color.primary_dark));
+        if (view instanceof TextView) {
+            ((TextView) view).setTextColor(Color.WHITE);
+        }
+        return view;
+    }
+}

android/app/src/main/java/com/example/petstoremobile/api/AdoptionApi.java

@@ -1,12 +1,14 @@
 package com.example.petstoremobile.api;
 
 import com.example.petstoremobile.dtos.AdoptionDTO;
+import com.example.petstoremobile.dtos.BulkDeleteRequest;
 import com.example.petstoremobile.dtos.PageResponse;
 
 import retrofit2.Call;
 import retrofit2.http.Body;
 import retrofit2.http.DELETE;
 import retrofit2.http.GET;
+import retrofit2.http.HTTP;
 import retrofit2.http.POST;
 import retrofit2.http.PUT;
 import retrofit2.http.Path;
@@ -17,7 +19,12 @@ public interface AdoptionApi {
     @GET("api/v1/adoptions")
     Call<PageResponse<AdoptionDTO>> getAllAdoptions(
             @Query("page") int page,
-            @Query("size") int size);
+            @Query("size") int size,
+            @Query("q") String query,
+            @Query("status") String status,
+            @Query("storeId") Long storeId,
+            @Query("date") String date,
+            @Query("employeeId") Long employeeId);
 
     @GET("api/v1/adoptions/{id}")
     Call<AdoptionDTO> getAdoptionById(@Path("id") Long id);
@@ -30,5 +37,7 @@ public interface AdoptionApi {
 
     @DELETE("api/v1/adoptions/{id}")
     Call<Void> deleteAdoption(@Path("id") Long id);
-}
 
+    @HTTP(method = "DELETE", path = "api/v1/adoptions", hasBody = true)
+    Call<Void> bulkDeleteAdoptions(@Body BulkDeleteRequest request);
+}

android/app/src/main/java/com/example/petstoremobile/api/AppointmentApi.java

@@ -1,12 +1,14 @@
 package com.example.petstoremobile.api;
 
 import com.example.petstoremobile.dtos.AppointmentDTO;
+import com.example.petstoremobile.dtos.BulkDeleteRequest;
 import com.example.petstoremobile.dtos.PageResponse;
 
 import retrofit2.Call;
 import retrofit2.http.Body;
 import retrofit2.http.DELETE;
 import retrofit2.http.GET;
+import retrofit2.http.HTTP;
 import retrofit2.http.POST;
 import retrofit2.http.PUT;
 import retrofit2.http.Path;
@@ -17,7 +19,12 @@ public interface AppointmentApi {
     @GET("api/v1/appointments")
     Call<PageResponse<AppointmentDTO>> getAllAppointments(
             @Query("page") int page,
-            @Query("size") int size);
+            @Query("size") int size,
+            @Query("q") String query,
+            @Query("status") String status,
+            @Query("storeId") Long storeId,
+            @Query("date") String date,
+            @Query("employeeId") Long employeeId);
 
     @GET("api/v1/appointments/{id}")
     Call<AppointmentDTO> getAppointmentById(@Path("id") Long id);
@@ -30,4 +37,7 @@ public interface AppointmentApi {
 
     @DELETE("api/v1/appointments/{id}")
     Call<Void> deleteAppointment(@Path("id") Long id);
+
+    @HTTP(method = "DELETE", path = "api/v1/appointments", hasBody = true)
+    Call<Void> bulkDeleteAppointments(@Body BulkDeleteRequest request);
 }

android/app/src/main/java/com/example/petstoremobile/api/InventoryApi.java

@@ -2,13 +2,13 @@ package com.example.petstoremobile.api;
 
 import com.example.petstoremobile.dtos.BulkDeleteRequest;
 import com.example.petstoremobile.dtos.InventoryDTO;
-import com.example.petstoremobile.dtos.InventoryRequest;
 import com.example.petstoremobile.dtos.PageResponse;
 
 import retrofit2.Call;
 import retrofit2.http.Body;
 import retrofit2.http.DELETE;
 import retrofit2.http.GET;
+import retrofit2.http.HTTP;
 import retrofit2.http.POST;
 import retrofit2.http.PUT;
 import retrofit2.http.Path;
@@ -16,12 +16,12 @@ import retrofit2.http.Query;
 
 public interface InventoryApi {
 
-    // GET /api/v1/inventory?q=...&page=...&size=...
     @GET("api/v1/inventory")
     Call<PageResponse<InventoryDTO>> getAllInventory(
-            @Query("q") String query,
             @Query("page") int page,
             @Query("size") int size,
+            @Query("q") String query,
+            @Query("storeId") Long storeId,
             @Query("sort") String sort);
 
     // GET /api/v1/inventory/{id}
@@ -30,17 +30,17 @@ public interface InventoryApi {
 
     // POST /api/v1/inventory
     @POST("api/v1/inventory")
-    Call<InventoryDTO> createInventory(@Body InventoryRequest request);
+    Call<InventoryDTO> createInventory(@Body InventoryDTO request);
 
     // PUT /api/v1/inventory/{id}
     @PUT("api/v1/inventory/{id}")
-    Call<InventoryDTO> updateInventory(@Path("id") Long id, @Body InventoryRequest request);
+    Call<InventoryDTO> updateInventory(@Path("id") Long id, @Body InventoryDTO request);
 
     // DELETE /api/v1/inventory/{id}
     @DELETE("api/v1/inventory/{id}")
     Call<Void> deleteInventory(@Path("id") Long id);
 
     // DELETE /api/v1/inventory (bulk delete)
-    @DELETE("api/v1/inventory")
+    @HTTP(method = "DELETE", path = "api/v1/inventory", hasBody = true)
     Call<Void> bulkDeleteInventory(@Body BulkDeleteRequest request);
 }

android/app/src/main/java/com/example/petstoremobile/api/PetApi.java

@@ -1,5 +1,6 @@
 package com.example.petstoremobile.api;
 
+import com.example.petstoremobile.dtos.BulkDeleteRequest;
 import com.example.petstoremobile.dtos.PageResponse;
 import com.example.petstoremobile.dtos.PetDTO;
 
@@ -8,6 +9,7 @@ import retrofit2.Call;
 import retrofit2.http.Body;
 import retrofit2.http.DELETE;
 import retrofit2.http.GET;
+import retrofit2.http.HTTP;
 import retrofit2.http.Multipart;
 import retrofit2.http.POST;
 import retrofit2.http.PUT;
@@ -20,11 +22,16 @@ public interface PetApi {
     // endpoint for downloading the pet's image file
     String PET_IMAGE_PATH = "api/v1/pets/%d/image";
 
-    // Get all pets
+    // Get all pets with filters
     @GET("api/v1/pets")
     Call<PageResponse<PetDTO>> getAllPets(
             @Query("page") int page,
-            @Query("size") int size
+            @Query("size") int size,
+            @Query("q") String query,
+            @Query("status") String status,
+            @Query("species") String species,
+            @Query("storeId") Long storeId,
+            @Query("sort") String sort
     );
 
     // Get pet by id
@@ -43,9 +50,17 @@ public interface PetApi {
     @DELETE("api/v1/pets/{id}")
     Call<Void> deletePet(@Path("id") Long id);
 
+    // Bulk delete pets
+    @HTTP(method = "DELETE", path = "api/v1/pets", hasBody = true)
+    Call<Void> bulkDeletePets(@Body BulkDeleteRequest request);
+
     // Upload pet image
     @Multipart
     @POST("api/v1/pets/{id}/image")
     Call<Void> uploadPetImage(@Path("id") Long id, @Part MultipartBody.Part image);
 
+    // Delete pet image
+    @DELETE("api/v1/pets/{id}/image")
+    Call<Void> deletePetImage(@Path("id") Long id);
+
 }

android/app/src/main/java/com/example/petstoremobile/api/ProductApi.java

@@ -2,16 +2,20 @@ package com.example.petstoremobile.api;
 
 import com.example.petstoremobile.dtos.PageResponse;
 import com.example.petstoremobile.dtos.ProductDTO;
+import okhttp3.MultipartBody;
 import retrofit2.Call;
 import retrofit2.http.*;
 
 public interface ProductApi {
+    String PRODUCT_IMAGE_PATH = "api/v1/products/%d/image";
 
     @GET("api/v1/products")
     Call<PageResponse<ProductDTO>> getAllProducts(
             @Query("q") String query,
+            @Query("categoryId") Long categoryId,
             @Query("page") int page,
-            @Query("size") int size);
+            @Query("size") int size,
+            @Query("sort") String sort);
 
     @GET("api/v1/products/{id}")
     Call<ProductDTO> getProductById(@Path("id") Long id);
@@ -24,4 +28,11 @@ public interface ProductApi {
 
     @DELETE("api/v1/products/{id}")
     Call<Void> deleteProduct(@Path("id") Long id);
+
+    @Multipart
+    @POST("api/v1/products/{id}/image")
+    Call<Void> uploadProductImage(@Path("id") Long id, @Part MultipartBody.Part image);
+
+    @DELETE("api/v1/products/{id}/image")
+    Call<Void> deleteProductImage(@Path("id") Long id);
 }

android/app/src/main/java/com/example/petstoremobile/api/ProductSupplierApi.java

@@ -1,5 +1,6 @@
 package com.example.petstoremobile.api;
 
+import com.example.petstoremobile.dtos.BulkDeleteRequest;
 import com.example.petstoremobile.dtos.PageResponse;
 import com.example.petstoremobile.dtos.ProductSupplierDTO;
 import retrofit2.Call;
@@ -10,7 +11,16 @@ public interface ProductSupplierApi {
     @GET("api/v1/product-suppliers")
     Call<PageResponse<ProductSupplierDTO>> getAllProductSuppliers(
             @Query("page") int page,
-            @Query("size") int size);
+            @Query("size") int size,
+            @Query("q") String query,
+            @Query("productId") Long productId,
+            @Query("supplierId") Long supplierId,
+            @Query("sort") String sort);
+
+    @GET("api/v1/product-suppliers/{productId}/{supplierId}")
+    Call<ProductSupplierDTO> getProductSupplierById(
+            @Path("productId") Long productId,
+            @Path("supplierId") Long supplierId);
 
     @POST("api/v1/product-suppliers")
     Call<ProductSupplierDTO> createProductSupplier(@Body ProductSupplierDTO dto);
@@ -25,4 +35,6 @@ public interface ProductSupplierApi {
     Call<Void> deleteProductSupplier(
             @Path("productId") Long productId,
             @Path("supplierId") Long supplierId);
+    @HTTP(method = "DELETE", path = "api/v1/product-suppliers", hasBody = true)
+    Call<Void> bulkDeleteProductSuppliers(@Body BulkDeleteRequest request);
 }

android/app/src/main/java/com/example/petstoremobile/api/PurchaseOrderApi.java

@@ -12,7 +12,10 @@ public interface PurchaseOrderApi {
     @GET("api/v1/purchase-orders")
     Call<PageResponse<PurchaseOrderDTO>> getAllPurchaseOrders(
             @Query("page") int page,
-            @Query("size") int size);
+            @Query("size") int size,
+            @Query("q") String query,
+            @Query("storeId") Long storeId,
+            @Query("sort") String sort);
 
     @GET("api/v1/purchase-orders/{id}")
     Call<PurchaseOrderDTO> getPurchaseOrderById(@Path("id") Long id);

android/app/src/main/java/com/example/petstoremobile/api/RetrofitClient.java

@@ -2,9 +2,12 @@ package com.example.petstoremobile.api;
 
 import android.content.Context;
 import android.os.Build;
+import android.util.Log;
 
+import com.example.petstoremobile.BuildConfig;
 import com.example.petstoremobile.api.auth.AuthApi;
 import com.example.petstoremobile.api.auth.AuthInterceptor;
+import com.example.petstoremobile.api.auth.TokenManager;
 
 import okhttp3.OkHttpClient;
 import okhttp3.logging.HttpLoggingInterceptor;
@@ -13,29 +16,30 @@ import retrofit2.converter.gson.GsonConverterFactory;
 
 import java.util.concurrent.TimeUnit;
 
-//Retrofit client Used for API calls
+//Retrofit client Used for API calls TODO: DELETE THIS FILE AFTER MERGE NOW THAT WE ARE USING HILT AND NETWORKMODULE
 public class RetrofitClient {
+    private static final String TAG = "RetrofitClient";
     public static final String BASE_URL = getBaseUrl();
 
     // Helper function to determine BASE_URL based on whether we are testing on an emulator or a real device
     private static String getBaseUrl() {
-        if (Build.FINGERPRINT.contains("generic")
-                || Build.FINGERPRINT.contains("unknown")
+        String url = isEmulator() ? BuildConfig.EMULATOR_BACKEND_URL : BuildConfig.DEVICE_BACKEND_URL;
+        Log.i(TAG, "Using backend URL: " + url + " (emulator=" + isEmulator() + ")");
+        return url;
+    }
+
+    private static boolean isEmulator() {
+        return Build.FINGERPRINT.startsWith("generic")
+                || Build.FINGERPRINT.startsWith("unknown")
                 || Build.MODEL.contains("google_sdk")
                 || Build.MODEL.contains("Emulator")
                 || Build.MODEL.contains("Android SDK built for x86")
                 || Build.MANUFACTURER.contains("Genymotion")
-                || (Build.BRAND.startsWith("generic") && Build.DEVICE.startsWith("generic"))
-                || "google_sdk".equals(Build.PRODUCT)) {
-            return "http://10.0.2.2:8080/"; //emulator testing
-        }
-        else {
-            return "http://10.0.0.200:8080/"; //Hardware testing
-        }
-
-        /*else {
-            return "http://192.168.1.148:8080/"; //Hardware testing
-        } */
+                || Build.HARDWARE.contains("goldfish")
+                || Build.HARDWARE.contains("ranchu")
+                || Build.PRODUCT.contains("sdk")
+                || Build.PRODUCT.contains("sdk_gphone")
+                || (Build.BRAND.startsWith("generic") && Build.DEVICE.startsWith("generic"));
     }
 
     private static Retrofit retrofit = null;
@@ -47,7 +51,7 @@ public class RetrofitClient {
 
         OkHttpClient client = new OkHttpClient.Builder()
                 .addInterceptor(interceptor)
-                .addInterceptor(new AuthInterceptor(context))
+                .addInterceptor(new AuthInterceptor(new TokenManager(context)))
                 .connectTimeout(30, TimeUnit.SECONDS)
                 .readTimeout(30, TimeUnit.SECONDS)
                 .writeTimeout(30, TimeUnit.SECONDS)
@@ -131,8 +135,9 @@ public class RetrofitClient {
     public static RefundApi getRefundApi(Context context) {
         return getClient(context).create(RefundApi.class);
     }
+
     public static EmployeeApi getEmployeeApi(Context context) {
         return getClient(context).create(EmployeeApi.class);
     }
 
-}
+}

android/app/src/main/java/com/example/petstoremobile/api/SaleApi.java

@@ -2,8 +2,13 @@ package com.example.petstoremobile.api;
 
 import com.example.petstoremobile.dtos.PageResponse;
 import com.example.petstoremobile.dtos.SaleDTO;
+
 import retrofit2.Call;
-import retrofit2.http.*;
+import retrofit2.http.Body;
+import retrofit2.http.GET;
+import retrofit2.http.POST;
+import retrofit2.http.Path;
+import retrofit2.http.Query;
 
 public interface SaleApi {
 

android/app/src/main/java/com/example/petstoremobile/api/ServiceApi.java

@@ -1,5 +1,6 @@
 package com.example.petstoremobile.api;
 
+import com.example.petstoremobile.dtos.BulkDeleteRequest;
 import com.example.petstoremobile.dtos.PageResponse;
 import com.example.petstoremobile.dtos.ServiceDTO;
 
@@ -7,6 +8,7 @@ import retrofit2.Call;
 import retrofit2.http.Body;
 import retrofit2.http.DELETE;
 import retrofit2.http.GET;
+import retrofit2.http.HTTP;
 import retrofit2.http.POST;
 import retrofit2.http.PUT;
 import retrofit2.http.Path;
@@ -18,7 +20,9 @@ public interface ServiceApi {
     @GET("api/v1/services")
     Call<PageResponse<ServiceDTO>> getAllServices(
             @Query("page") int page,
-            @Query("size") int size
+            @Query("size") int size,
+            @Query("q") String query,
+            @Query("sort") String sort
     );
 
     // Get service by id
@@ -36,4 +40,8 @@ public interface ServiceApi {
     // Delete service
     @DELETE("api/v1/services/{id}")
     Call<Void> deleteService(@Path("id") Long id);
+
+    // Bulk delete services
+    @HTTP(method = "DELETE", path = "api/v1/services", hasBody = true)
+    Call<Void> bulkDeleteServices(@Body BulkDeleteRequest request);
 }

android/app/src/main/java/com/example/petstoremobile/api/SupplierApi.java

@@ -1,5 +1,6 @@
 package com.example.petstoremobile.api;
 
+import com.example.petstoremobile.dtos.BulkDeleteRequest;
 import com.example.petstoremobile.dtos.PageResponse;
 import com.example.petstoremobile.dtos.SupplierDTO;
 
@@ -7,6 +8,7 @@ import retrofit2.Call;
 import retrofit2.http.Body;
 import retrofit2.http.DELETE;
 import retrofit2.http.GET;
+import retrofit2.http.HTTP;
 import retrofit2.http.POST;
 import retrofit2.http.PUT;
 import retrofit2.http.Path;
@@ -18,7 +20,9 @@ public interface SupplierApi {
     @GET("api/v1/suppliers")
     Call<PageResponse<SupplierDTO>> getAllSuppliers(
             @Query("page") int page,
-            @Query("size") int size
+            @Query("size") int size,
+            @Query("q") String query,
+            @Query("sort") String sort
     );
 
     // Get supplier by id
@@ -36,4 +40,8 @@ public interface SupplierApi {
     // Delete supplier
     @DELETE("api/v1/suppliers/{id}")
     Call<Void> deleteSupplier(@Path("id") Long id);
+
+    // Bulk delete suppliers
+    @HTTP(method = "DELETE", path = "api/v1/suppliers", hasBody = true)
+    Call<Void> bulkDeleteSuppliers(@Body BulkDeleteRequest request);
 }

android/app/src/main/java/com/example/petstoremobile/api/UserApi.java

@@ -0,0 +1,13 @@
+package com.example.petstoremobile.api;
+
+import com.example.petstoremobile.dtos.PageResponse;
+import com.example.petstoremobile.dtos.UserDTO;
+
+import retrofit2.Call;
+import retrofit2.http.GET;
+import retrofit2.http.Query;
+
+public interface UserApi {
+    @GET("api/v1/users")
+    Call<PageResponse<UserDTO>> getUsers(@Query("role") String role, @Query("page") int page, @Query("size") int size);
+}

android/app/src/main/java/com/example/petstoremobile/api/auth/AuthApi.java

@@ -1,6 +1,7 @@
 package com.example.petstoremobile.api.auth;
 
 import com.example.petstoremobile.dtos.AuthDTO;
+import com.example.petstoremobile.dtos.AvatarUploadResponse;
 import com.example.petstoremobile.dtos.UserDTO;
 
 import java.util.Map;
@@ -8,6 +9,7 @@ import java.util.Map;
 import okhttp3.MultipartBody;
 import retrofit2.Call;
 import retrofit2.http.Body;
+import retrofit2.http.DELETE;
 import retrofit2.http.GET;
 import retrofit2.http.Multipart;
 import retrofit2.http.POST;
@@ -35,6 +37,10 @@ public interface AuthApi {
     //upload avatar endpoint
     @Multipart
     @POST("api/v1/auth/me/avatar")
-    Call<UserDTO> uploadAvatar(@Part MultipartBody.Part avatar);
+    Call<AvatarUploadResponse> uploadAvatar(@Part MultipartBody.Part avatar);
+
+    //delete avatar endpoint
+    @DELETE("api/v1/auth/me/avatar")
+    Call<Void> deleteAvatar();
 
 }

android/app/src/main/java/com/example/petstoremobile/api/auth/AuthInterceptor.java

@@ -1,7 +1,5 @@
 package com.example.petstoremobile.api.auth;
 
-import android.content.Context;
-
 import androidx.annotation.NonNull;
 
 import java.io.IOException;
@@ -15,8 +13,8 @@ public class AuthInterceptor implements Interceptor {
 
     private final TokenManager tokenManager;
 
-    public AuthInterceptor(Context context) {
-        this.tokenManager = TokenManager.getInstance(context);
+    public AuthInterceptor(TokenManager tokenManager) {
+        this.tokenManager = tokenManager;
     }
 
     @NonNull

android/app/src/main/java/com/example/petstoremobile/api/auth/TokenManager.java

@@ -3,7 +3,12 @@ package com.example.petstoremobile.api.auth;
 import android.content.Context;
 import android.content.SharedPreferences;
 
-//Store login token in shared preferences
+import javax.inject.Inject;
+import javax.inject.Singleton;
+
+import dagger.hilt.android.qualifiers.ApplicationContext;
+
+@Singleton
 public class TokenManager {
     private static final String TOKEN_KEY = "token";
     private static final String USERNAME_KEY = "username";
@@ -11,20 +16,13 @@ public class TokenManager {
     private static final String PREFS_NAME = "auth_prefs";
     private static final String USER_ID_KEY = "user_id";
 
-    private static TokenManager instance;
     private SharedPreferences prefs;
 
-    private TokenManager(Context context) {
+    @Inject
+    public TokenManager(@ApplicationContext Context context) {
         prefs = context.getSharedPreferences(PREFS_NAME, Context.MODE_PRIVATE);
     }
 
-    public static TokenManager getInstance(Context context) {
-        if (instance == null) {
-            instance = new TokenManager(context);
-        }
-        return instance;
-    }
-
     //save login data after login
     public void saveLoginData(String token, String username, String role) {
         prefs.edit()
@@ -65,6 +63,4 @@ public class TokenManager {
     public void clearLoginData() {
         prefs.edit().clear().apply();
     }
-
-
-}
+}

android/app/src/main/java/com/example/petstoremobile/di/NetworkModule.java

@@ -0,0 +1,182 @@
+package com.example.petstoremobile.di;
+
+import android.content.Context;
+import android.os.Build;
+
+import com.example.petstoremobile.BuildConfig;
+import com.example.petstoremobile.api.*;
+import com.example.petstoremobile.api.auth.AuthApi;
+import com.example.petstoremobile.api.auth.AuthInterceptor;
+import com.example.petstoremobile.api.auth.TokenManager;
+
+import java.util.concurrent.TimeUnit;
+
+import javax.inject.Named;
+import javax.inject.Singleton;
+
+import dagger.Module;
+import dagger.Provides;
+import dagger.hilt.InstallIn;
+import dagger.hilt.android.qualifiers.ApplicationContext;
+import dagger.hilt.components.SingletonComponent;
+import okhttp3.OkHttpClient;
+import okhttp3.logging.HttpLoggingInterceptor;
+import retrofit2.Retrofit;
+import retrofit2.converter.gson.GsonConverterFactory;
+
+//Module to provide dependencies injection for the api
+@Module
+@InstallIn(SingletonComponent.class)
+public class NetworkModule {
+
+    @Provides
+    @Singleton
+    @Named("baseUrl")
+    public static String provideBaseUrl() {
+        return isEmulator() ? BuildConfig.EMULATOR_BACKEND_URL : BuildConfig.DEVICE_BACKEND_URL;
+    }
+
+    // Check if the device is an emulator
+    private static boolean isEmulator() {
+        return Build.FINGERPRINT.startsWith("generic")
+                || Build.FINGERPRINT.startsWith("unknown")
+                || Build.MODEL.contains("google_sdk")
+                || Build.MODEL.contains("Emulator")
+                || Build.MODEL.contains("Android SDK built for x86")
+                || Build.MANUFACTURER.contains("Genymotion")
+                || Build.HARDWARE.contains("goldfish")
+                || Build.HARDWARE.contains("ranchu")
+                || Build.PRODUCT.contains("sdk")
+                || Build.PRODUCT.contains("sdk_gphone")
+                || (Build.BRAND.startsWith("generic") && Build.DEVICE.startsWith("generic"));
+    }
+
+    @Provides
+    @Singleton
+    public static OkHttpClient provideOkHttpClient(TokenManager tokenManager) {
+        HttpLoggingInterceptor interceptor = new HttpLoggingInterceptor();
+        interceptor.setLevel(HttpLoggingInterceptor.Level.BODY);
+
+        return new OkHttpClient.Builder()
+                .addInterceptor(interceptor)
+                .addInterceptor(new AuthInterceptor(tokenManager))
+                .connectTimeout(30, TimeUnit.SECONDS)
+                .readTimeout(30, TimeUnit.SECONDS)
+                .writeTimeout(30, TimeUnit.SECONDS)
+                .build();
+    }
+
+    //build the retrofit instance
+    @Provides
+    @Singleton
+    public static Retrofit provideRetrofit(@Named("baseUrl") String baseUrl, OkHttpClient client) {
+        return new Retrofit.Builder()
+                .baseUrl(baseUrl)
+                .addConverterFactory(GsonConverterFactory.create())
+                .client(client)
+                .build();
+    }
+
+    //associate the api with the retrofit instance
+    @Provides
+    @Singleton
+    public static PetApi providePetApi(Retrofit retrofit) {
+        return retrofit.create(PetApi.class);
+    }
+
+    @Provides
+    @Singleton
+    public static ServiceApi provideServiceApi(Retrofit retrofit) {
+        return retrofit.create(ServiceApi.class);
+    }
+
+    @Provides
+    @Singleton
+    public static SupplierApi provideSupplierApi(Retrofit retrofit) {
+        return retrofit.create(SupplierApi.class);
+    }
+
+    @Provides
+    @Singleton
+    public static AdoptionApi provideAdoptionApi(Retrofit retrofit) {
+        return retrofit.create(AdoptionApi.class);
+    }
+
+    @Provides
+    @Singleton
+    public static AppointmentApi provideAppointmentApi(Retrofit retrofit) {
+        return retrofit.create(AppointmentApi.class);
+    }
+
+    @Provides
+    @Singleton
+    public static ProductApi provideProductApi(Retrofit retrofit) {
+        return retrofit.create(ProductApi.class);
+    }
+
+    @Provides
+    @Singleton
+    public static SaleApi provideSaleApi(Retrofit retrofit) {
+        return retrofit.create(SaleApi.class);
+    }
+
+    @Provides
+    @Singleton
+    public static PurchaseOrderApi providePurchaseOrderApi(Retrofit retrofit) {
+        return retrofit.create(PurchaseOrderApi.class);
+    }
+
+    @Provides
+    @Singleton
+    public static ProductSupplierApi provideProductSupplierApi(Retrofit retrofit) {
+        return retrofit.create(ProductSupplierApi.class);
+    }
+
+    @Provides
+    @Singleton
+    public static InventoryApi provideInventoryApi(Retrofit retrofit) {
+        return retrofit.create(InventoryApi.class);
+    }
+
+    @Provides
+    @Singleton
+    public static AuthApi provideAuthApi(Retrofit retrofit) {
+        return retrofit.create(AuthApi.class);
+    }
+
+    @Provides
+    @Singleton
+    public static ChatApi provideChatApi(Retrofit retrofit) {
+        return retrofit.create(ChatApi.class);
+    }
+
+    @Provides
+    @Singleton
+    public static CustomerApi provideCustomerApi(Retrofit retrofit) {
+        return retrofit.create(CustomerApi.class);
+    }
+
+    @Provides
+    @Singleton
+    public static MessageApi provideMessageApi(Retrofit retrofit) {
+        return retrofit.create(MessageApi.class);
+    }
+
+    @Provides
+    @Singleton
+    public static StoreApi provideStoreApi(Retrofit retrofit) {
+        return retrofit.create(StoreApi.class);
+    }
+
+    @Provides
+    @Singleton
+    public static CategoryApi provideCategoryApi(Retrofit retrofit) {
+        return retrofit.create(CategoryApi.class);
+    }
+
+    @Provides
+    @Singleton
+    public static UserApi provideUserApi(Retrofit retrofit) {
+        return retrofit.create(UserApi.class);
+    }
+}

android/app/src/main/java/com/example/petstoremobile/dtos/AdoptionDTO.java

@@ -9,88 +9,68 @@ public class AdoptionDTO {
     private String petName;
     private Long customerId;
     private String customerName;
+    private Long employeeId;
+    private String employeeName;
+    private Long sourceStoreId;
+    private String sourceStoreName;
     private String adoptionDate;
     private String adoptionStatus;
     private BigDecimal adoptionFee;
-    private Long employeeId;
-    private String employeeName;
     private String createdAt;
     private String updatedAt;
 
-    // Constructor for create/update requests
-    public AdoptionDTO(Long petId, Long customerId, String adoptionDate, String adoptionStatus, Long employeeId) {
+    public AdoptionDTO() {}
+
+    public AdoptionDTO(Long petId, Long customerId, Long employeeId, Long sourceStoreId,
+                       String adoptionDate, String adoptionStatus, BigDecimal adoptionFee) {
         this.petId = petId;
         this.customerId = customerId;
+        this.employeeId = employeeId;
+        this.sourceStoreId = sourceStoreId;
         this.adoptionDate = adoptionDate;
         this.adoptionStatus = adoptionStatus;
-        this.employeeId = employeeId;
+        this.adoptionFee = adoptionFee;
     }
 
-    public Long getAdoptionId() {
+    public Long getAdoptionId() { return adoptionId; }
+    public void setAdoptionId(Long adoptionId) { this.adoptionId = adoptionId; }
 
-        return adoptionId;
-    }
+    public Long getPetId() { return petId; }
+    public void setPetId(Long petId) { this.petId = petId; }
 
-    public Long getPetId() {
+    public String getPetName() { return petName; }
+    public void setPetName(String petName) { this.petName = petName; }
 
-        return petId;
-    }
+    public Long getCustomerId() { return customerId; }
+    public void setCustomerId(Long customerId) { this.customerId = customerId; }
 
-    public String getPetName() {
+    public String getCustomerName() { return customerName; }
+    public void setCustomerName(String customerName) { this.customerName = customerName; }
 
-        return petName;
-    }
+    public Long getEmployeeId() { return employeeId; }
+    public void setEmployeeId(Long employeeId) { this.employeeId = employeeId; }
 
-    public Long getCustomerId() {
+    public String getEmployeeName() { return employeeName; }
+    public void setEmployeeName(String employeeName) { this.employeeName = employeeName; }
 
-        return customerId;
-    }
+    public Long getSourceStoreId() { return sourceStoreId; }
+    public void setSourceStoreId(Long sourceStoreId) { this.sourceStoreId = sourceStoreId; }
 
-    public String getCustomerName() {
+    public String getSourceStoreName() { return sourceStoreName; }
+    public void setSourceStoreName(String sourceStoreName) { this.sourceStoreName = sourceStoreName; }
 
-        return customerName;
-    }
+    public String getAdoptionDate() { return adoptionDate; }
+    public void setAdoptionDate(String adoptionDate) { this.adoptionDate = adoptionDate; }
 
-    public String getAdoptionDate() {
+    public String getAdoptionStatus() { return adoptionStatus; }
+    public void setAdoptionStatus(String adoptionStatus) { this.adoptionStatus = adoptionStatus; }
 
-        return adoptionDate;
-    }
+    public BigDecimal getAdoptionFee() { return adoptionFee; }
+    public void setAdoptionFee(BigDecimal adoptionFee) { this.adoptionFee = adoptionFee; }
 
-    public String getEmployeeName() {
+    public String getCreatedAt() { return createdAt; }
+    public void setCreatedAt(String createdAt) { this.createdAt = createdAt; }
 
-        return employeeName;
-    }
-
-    public Long getEmployeeId() {
-        return employeeId;
-    }
-
-    public String getAdoptionStatus() {
-
-        return adoptionStatus;
-    }
-
-    public String getStatus() {
-
-        return adoptionStatus;
-    }
-
-    public BigDecimal getAdoptionFee() {
-
-        return adoptionFee;
-    }
-
-    public String getCreatedAt() {
-
-        return createdAt;
-    }
-
-    public String getUpdatedAt() {
-
-        return updatedAt;
-    }
-
-
-
-
-}
+    public String getUpdatedAt() { return updatedAt; }
+    public void setUpdatedAt(String updatedAt) { this.updatedAt = updatedAt; }
+}

android/app/src/main/java/com/example/petstoremobile/dtos/AppointmentDTO.java

@@ -1,10 +1,7 @@
 package com.example.petstoremobile.dtos;
 
-import java.math.BigDecimal;
-import java.util.List;
-
 public class AppointmentDTO {
-    // Response fields (from server)
+
     private Long appointmentId;
     private Long customerId;
     private String customerName;
@@ -12,143 +9,72 @@ public class AppointmentDTO {
     private String storeName;
     private Long serviceId;
     private String serviceName;
-
     private Long employeeId;
     private String employeeName;
     private String appointmentDate;
     private String appointmentTime;
     private String appointmentStatus;
-    private List<String> petNames;
-    private List<Long> petIds;
-
+    private String petName;
+    private Long petId;
     private String createdAt;
     private String updatedAt;
 
-
-
-    // Constructor for CREATE/UPDATE request body
-    // Matches AppointmentRequest exactly
     public AppointmentDTO(Long customerId, Long storeId, Long serviceId,
                           String appointmentDate, String appointmentTime,
-                          String appointmentStatus, List<Long> petIds) {
+                          String appointmentStatus, Long petId) {
+        this(customerId, storeId, serviceId, null, appointmentDate, appointmentTime, appointmentStatus, petId);
+    }
+
+    public AppointmentDTO(Long customerId, Long storeId, Long serviceId, Long employeeId,
+                          String appointmentDate, String appointmentTime,
+                          String appointmentStatus, Long petId) {
         this.customerId = customerId;
         this.storeId = storeId;
         this.serviceId = serviceId;
+        this.employeeId = employeeId;
         this.appointmentDate = appointmentDate;
         this.appointmentTime = appointmentTime;
         this.appointmentStatus = appointmentStatus;
-        this.petIds = petIds;
-        this.employeeId = employeeId;
+        this.petId = petId;
     }
 
-    // Getters
-    public Long getAppointmentId() {
+    public Long getAppointmentId() { return appointmentId; }
 
-        return appointmentId;
-    }
+    public Long getCustomerId() { return customerId; }
 
-    public Long getCustomerId() {
+    public String getCustomerName() { return customerName; }
 
-        return customerId;
-    }
+    public Long getStoreId() { return storeId; }
 
-    public String getCustomerName() {
+    public String getStoreName() { return storeName; }
 
-        return customerName;
-    }
+    public Long getServiceId() { return serviceId; }
 
-    public Long getStoreId() {
+    public String getServiceName() { return serviceName; }
 
-        return storeId;
-    }
+    public Long getEmployeeId() { return employeeId; }
 
-    public String getStoreName() {
+    public String getEmployeeName() { return employeeName; }
 
-        return storeName;
-    }
+    public String getAppointmentDate() { return appointmentDate; }
 
-    public Long getServiceId() {
+    public String getAppointmentTime() { return appointmentTime; }
 
-        return serviceId;
-    }
+    public String getAppointmentStatus() { return appointmentStatus; }
 
-    public String getServiceName() {
+    public String getPetName() { return petName; }
 
-        return serviceName;
-    }
+    public Long getPetId() { return petId; }
 
-    public String getAppointmentDate() {
+    public String getCreatedAt() { return createdAt; }
 
-        return appointmentDate;
-    }
+    public String getUpdatedAt() { return updatedAt; }
 
-    public String getAppointmentTime() {
+    public Long getPetID() { return petId; }
 
-        return appointmentTime;
-    }
-
-    public String getAppointmentStatus() {
-
-        return appointmentStatus;
-    }
-
-    public List<String> getPetNames() {
-
-        return petNames;
-    }
-
-    public List<Long> getPetIds() {
-
-        return petIds;
-    }
-
-
-
-    public String getCreatedAt() {
-
-        return createdAt;
-    }
-
-    public String getUpdatedAt() {
-
-        return updatedAt;
-    }
-
-    // Convenience getters for adapter/list display
-    public String getPetName() {
-        return (petNames != null && !petNames.isEmpty()) ? petNames.get(0) : "";
-    }
-
-    public Long getPetID() {
-
-        return (petIds != null && !petIds.isEmpty()) ? petIds.get(0) : null;
-    }
-
-    public Long getPetId() {
-
-        return getPetID();
-    }
-
-    // Keep old name so adapter doesn't break
-    public String getServiceType() {
-        return serviceName;
-    }
-
-    public Long getServiceID() {
-
-        return serviceId;
-    }
-
-    public String getEmployeeName() {
-
-        return employeeName;
-    }
-
-    // Status alias
-    public String getStatus() {
-
-        return appointmentStatus;
-    }
+    public String getServiceType() { return serviceName; }
 
+    public Long getServiceID() { return serviceId; }
 
+    public String getStatus() { return appointmentStatus; }
 }

android/app/src/main/java/com/example/petstoremobile/dtos/AvatarUploadResponse.java

@@ -0,0 +1,25 @@
+package com.example.petstoremobile.dtos;
+
+public class AvatarUploadResponse {
+    private String avatarUrl;
+    private String message;
+
+    public AvatarUploadResponse() {
+    }
+
+    public String getAvatarUrl() {
+        return avatarUrl;
+    }
+
+    public void setAvatarUrl(String avatarUrl) {
+        this.avatarUrl = avatarUrl;
+    }
+
+    public String getMessage() {
+        return message;
+    }
+
+    public void setMessage(String message) {
+        this.message = message;
+    }
+}

android/app/src/main/java/com/example/petstoremobile/dtos/BulkDeleteRequest.java

@@ -3,20 +3,20 @@ package com.example.petstoremobile.dtos;
 import java.util.List;
 
 public class BulkDeleteRequest {
-    private List<Long> ids;
+    private List<String> ids;
 
     public BulkDeleteRequest() {
     }
 
-    public BulkDeleteRequest(List<Long> ids) {
+    public BulkDeleteRequest(List<String> ids) {
         this.ids = ids;
     }
 
-    public List<Long> getIds() {
+    public List<String> getIds() {
         return ids;
     }
 
-    public void setIds(List<Long> ids) {
+    public void setIds(List<String> ids) {
         this.ids = ids;
     }
 }

android/app/src/main/java/com/example/petstoremobile/dtos/CustomerDTO.java

@@ -1,6 +1,9 @@
 package com.example.petstoremobile.dtos;
 
+import com.google.gson.annotations.SerializedName;
+
 public class CustomerDTO {
+    @SerializedName("id")
     private Long customerId;
     private String firstName;
     private String lastName;
@@ -12,18 +15,34 @@ public class CustomerDTO {
         return customerId;
     }
 
+    public void setCustomerId(Long customerId) {
+        this.customerId = customerId;
+    }
+
     public String getFirstName() {
         return firstName;
     }
 
+    public void setFirstName(String firstName) {
+        this.firstName = firstName;
+    }
+
     public String getLastName() {
         return lastName;
     }
 
+    public void setLastName(String lastName) {
+        this.lastName = lastName;
+    }
+
     public String getEmail() {
         return email;
     }
 
+    public void setEmail(String email) {
+        this.email = email;
+    }
+
     public String getFullName() {
         return firstName + " " + lastName;
     }
@@ -32,7 +51,15 @@ public class CustomerDTO {
         return createdAt;
     }
 
+    public void setCreatedAt(String createdAt) {
+        this.createdAt = createdAt;
+    }
+
     public String getUpdatedAt() {
         return updatedAt;
     }
-}
+
+    public void setUpdatedAt(String updatedAt) {
+        this.updatedAt = updatedAt;
+    }
+}

android/app/src/main/java/com/example/petstoremobile/dtos/InventoryDTO.java

@@ -6,6 +6,8 @@ public class InventoryDTO {
     private Long prodId;
     private String productName;
     private String categoryName;
+    private Long storeId;
+    private String storeName;
     private Integer quantity;
     private String createdAt;
     private String updatedAt;
@@ -14,8 +16,9 @@ public class InventoryDTO {
     }
 
     // Constructor for create/update requests (matches InventoryRequest)
-    public InventoryDTO(Long prodId, Integer quantity) {
+    public InventoryDTO(Long prodId, Long storeId, Integer quantity) {
         this.prodId = prodId;
+        this.storeId = storeId;
         this.quantity = quantity;
     }
 
@@ -51,6 +54,22 @@ public class InventoryDTO {
         this.categoryName = categoryName;
     }
 
+    public Long getStoreId() {
+        return storeId;
+    }
+
+    public void setStoreId(Long storeId) {
+        this.storeId = storeId;
+    }
+
+    public String getStoreName() {
+        return storeName;
+    }
+
+    public void setStoreName(String storeName) {
+        this.storeName = storeName;
+    }
+
     public Integer getQuantity() {
         return quantity;
     }

android/app/src/main/java/com/example/petstoremobile/dtos/InventoryRequest.java

@@ -1,31 +0,0 @@
-package com.example.petstoremobile.dtos;
-
-public class InventoryRequest {
-    private Long prodId;
-    private Integer quantity;
-
-    public InventoryRequest() {
-    }
-
-    public InventoryRequest(Long prodId, Integer quantity) {
-        this.prodId = prodId;
-        this.quantity = quantity;
-    }
-
-    public Long getProdId() {
-        return prodId;
-    }
-
-    public void setProdId(Long prodId) {
-        this.prodId = prodId;
-    }
-
-    public Integer getQuantity() {
-        return quantity;
-    }
-
-    public void setQuantity(Integer quantity) {
-        this.quantity = quantity;
-    }
-}
-

android/app/src/main/java/com/example/petstoremobile/dtos/MessageDTO.java

@@ -22,6 +22,15 @@ public class MessageDTO {
     @SerializedName("isRead")
     private Boolean isRead;
 
+    @SerializedName("attachmentUrl")
+    private String attachmentUrl;
+
+    @SerializedName("attachmentName")
+    private String attachmentName;
+
+    @SerializedName("attachmentType")
+    private String attachmentType;
+
     public MessageDTO() {}
 
     public Long getId() { return id; }
@@ -41,4 +50,13 @@ public class MessageDTO {
 
     public Boolean getIsRead() { return isRead; }
     public void setIsRead(Boolean isRead) { this.isRead = isRead; }
+
+    public String getAttachmentUrl() { return attachmentUrl; }
+    public void setAttachmentUrl(String attachmentUrl) { this.attachmentUrl = attachmentUrl; }
+
+    public String getAttachmentName() { return attachmentName; }
+    public void setAttachmentName(String attachmentName) { this.attachmentName = attachmentName; }
+
+    public String getAttachmentType() { return attachmentType; }
+    public void setAttachmentType(String attachmentType) { this.attachmentType = attachmentType; }
 }

android/app/src/main/java/com/example/petstoremobile/dtos/PetDTO.java

@@ -7,9 +7,13 @@ public class PetDTO {
     private String petBreed;
     private Integer petAge;
     private String petStatus;
-    private String petPrice;
+    private Double petPrice;
     private String createdAt;
     private String updatedAt;
+    private Long customerId;
+    private String customerName;
+    private Long storeId;
+    private String storeName;
 
     public Long getPetId() { return petId; }
     public void setPetId(Long petId) { this.petId = petId; }
@@ -29,12 +33,24 @@ public class PetDTO {
     public String getPetStatus() { return petStatus; }
     public void setPetStatus(String petStatus) { this.petStatus = petStatus; }
 
-    public String getPetPrice() { return petPrice; }
-    public void setPetPrice(String petPrice) { this.petPrice = petPrice; }
+    public Double getPetPrice() { return petPrice; }
+    public void setPetPrice(Double petPrice) { this.petPrice = petPrice; }
 
     public String getCreatedAt() { return createdAt; }
     public void setCreatedAt(String createdAt) { this.createdAt = createdAt; }
 
     public String getUpdatedAt() { return updatedAt; }
     public void setUpdatedAt(String updatedAt) { this.updatedAt = updatedAt; }
+
+    public Long getCustomerId() { return customerId; }
+    public void setCustomerId(Long customerId) { this.customerId = customerId; }
+
+    public String getCustomerName() { return customerName; }
+    public void setCustomerName(String customerName) { this.customerName = customerName; }
+
+    public Long getStoreId() { return storeId; }
+    public void setStoreId(Long storeId) { this.storeId = storeId; }
+
+    public String getStoreName() { return storeName; }
+    public void setStoreName(String storeName) { this.storeName = storeName; }
 }

android/app/src/main/java/com/example/petstoremobile/dtos/PurchaseOrderDTO.java

@@ -4,6 +4,8 @@ public class PurchaseOrderDTO {
     private Long purchaseOrderId;
     private Long supId;
     private String supplierName;
+    private Long storeId;
+    private String storeName;
     private String orderDate;
     private String status;
     private String createdAt;
@@ -21,6 +23,14 @@ public class PurchaseOrderDTO {
         return supplierName;
     }
 
+    public Long getStoreId() {
+        return storeId;
+    }
+
+    public String getStoreName() {
+        return storeName;
+    }
+
     public String getOrderDate() {
         return orderDate;
     }

android/app/src/main/java/com/example/petstoremobile/fragments/ChatFragment.java

@@ -1,47 +1,53 @@
 package com.example.petstoremobile.fragments;
 
+import android.app.Activity;
+import android.content.Intent;
+import android.database.Cursor;
+import android.net.Uri;
 import android.os.Bundle;
+import android.provider.OpenableColumns;
 import android.util.Log;
 import android.view.*;
-import android.widget.*;
+import android.view.inputmethod.EditorInfo;
+import android.widget.Toast;
+import androidx.activity.result.ActivityResultLauncher;
+import androidx.activity.result.contract.ActivityResultContracts;
 import androidx.annotation.NonNull;
 import androidx.core.view.GravityCompat;
-import androidx.drawerlayout.widget.DrawerLayout;
 import androidx.fragment.app.Fragment;
+import androidx.lifecycle.ViewModelProvider;
 import androidx.recyclerview.widget.LinearLayoutManager;
-import androidx.recyclerview.widget.RecyclerView;
+import com.bumptech.glide.Glide;
 import com.example.petstoremobile.R;
 import com.example.petstoremobile.adapters.ChatAdapter;
 import com.example.petstoremobile.adapters.MessageAdapter;
 import com.example.petstoremobile.api.auth.TokenManager;
-import com.example.petstoremobile.api.ChatApi;
-import com.example.petstoremobile.api.CustomerApi;
-import com.example.petstoremobile.api.MessageApi;
-import com.example.petstoremobile.api.RetrofitClient;
+import com.example.petstoremobile.databinding.FragmentChatBinding;
 import com.example.petstoremobile.dtos.ConversationDTO;
-import com.example.petstoremobile.dtos.CustomerDTO;
 import com.example.petstoremobile.dtos.MessageDTO;
-import com.example.petstoremobile.dtos.PageResponse;
 import com.example.petstoremobile.dtos.SendMessageRequest;
 import com.example.petstoremobile.models.Chat;
 import com.example.petstoremobile.models.Message;
 import com.example.petstoremobile.services.ChatNotificationService;
+import com.example.petstoremobile.utils.Resource;
+import com.example.petstoremobile.viewmodels.ChatViewModel;
 import com.example.petstoremobile.websocket.StompChatManager;
-import java.util.*;
-import java.util.stream.Collectors;
-import retrofit2.*;
 
+import java.util.*;
+
+import javax.inject.Inject;
+import javax.inject.Named;
+
+import dagger.hilt.android.AndroidEntryPoint;
+
+@AndroidEntryPoint
 public class ChatFragment extends Fragment implements ChatAdapter.OnChatClickListener, StompChatManager.MessageListener,
         StompChatManager.ConversationListener, StompChatManager.ConnectionListener {
 
     private static final String TAG = "ChatFragment";
 
-    // View
-    private DrawerLayout drawerLayout;
-    private RecyclerView rvChatList, rvMessages;
-    private EditText etMessage;
-    private Button btnSend;
-    private TextView tvChatTitle;
+    private FragmentChatBinding binding;
+    private ChatViewModel viewModel;
 
     // Adapters
     private ChatAdapter chatAdapter;
@@ -51,71 +57,108 @@ public class ChatFragment extends Fragment implements ChatAdapter.OnChatClickLis
     private final List<Chat> chatList = new ArrayList<>();
     private final List<Message> messageList = new ArrayList<>();
     private final Map<Long, String> customerNames = new HashMap<>();
+    private Uri pendingAttachmentUri;
 
-    // APIs
-    private ChatApi chatApi;
-    private CustomerApi customerApi;
-    private MessageApi messageApi;
+    @Inject TokenManager tokenManager;
+    @Inject @Named("baseUrl") String baseUrl;
 
     // chat
     private Long currentUserId;
     private Long activeConversationId;
     private StompChatManager stompChatManager;
+    private ActivityResultLauncher<Intent> attachmentLauncher;
 
+    /**
+     * Initializes the attachment launcher to handle file selection from the gallery.
+     */
+    @Override
+    public void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        viewModel = new ViewModelProvider(this).get(ChatViewModel.class);
+        attachmentLauncher = registerForActivityResult(
+                new ActivityResultContracts.StartActivityForResult(),
+                result -> {
+                    if (result.getResultCode() == Activity.RESULT_OK && result.getData() != null) {
+                        Uri uri = result.getData().getData();
+                        if (uri != null) {
+                            showAttachmentPreview(uri);
+                        }
+                    }
+                }
+        );
+    }
+
+    /**
+     * Inflates the layout, initializes UI components, and sets up click listeners for messaging.
+     */
     @Override
     public View onCreateView(@NonNull LayoutInflater inflater,
                              ViewGroup container, Bundle savedInstanceState) {
 
-        View view = inflater.inflate(R.layout.fragment_chat, container, false);
+        binding = FragmentChatBinding.inflate(inflater, container, false);
 
-        chatApi = RetrofitClient.getChatApi(requireContext());
-        customerApi = RetrofitClient.getCustomerApi(requireContext());
-        messageApi = RetrofitClient.getMessageApi(requireContext());
+        binding.btnHamburger.setOnClickListener(v -> binding.chatDrawerLayout.openDrawer(GravityCompat.START));
 
-        drawerLayout = view.findViewById(R.id.chatDrawerLayout);
-        rvChatList = view.findViewById(R.id.rvChatList);
-        rvMessages = view.findViewById(R.id.rvMessages);
-        etMessage = view.findViewById(R.id.etMessage);
-        btnSend = view.findViewById(R.id.btnSend);
-        tvChatTitle = view.findViewById(R.id.tvChatTitle);
+        // Set editor action listener for message field to send when enter is pressed
+        binding.etMessage.setOnEditorActionListener((v, actionId, event) -> {
+            if (actionId == EditorInfo.IME_ACTION_SEND || actionId == EditorInfo.IME_NULL) {
+                binding.btnSend.performClick();
+                return true;
+            }
+            return false;
+        });
 
-        ImageButton hamburger = view.findViewById(R.id.btnHamburger);
-        hamburger.setOnClickListener(v -> drawerLayout.openDrawer(GravityCompat.START));
-        btnSend.setOnClickListener(v -> sendMessage());
+        //When the send button is clicked check if there is an attachment and send using the correct helper function
+        binding.btnSend.setOnClickListener(v -> {
+            if (pendingAttachmentUri != null) {
+                sendWithAttachment(pendingAttachmentUri);
+            } else {
+                sendMessage();
+            }
+        });
+
+        //When the attachment button is clicked open the file picker
+        binding.btnAttach.setOnClickListener(v -> selectAttachment());
+        binding.btnRemoveAttachment.setOnClickListener(v -> removeAttachment());
 
         setupRecyclerViews();
         loadInitialData();
 
-        return view;
+        return binding.getRoot();
     }
 
+    /**
+     * Configures the RecyclerViews for the conversation list and the message history.
+     */
     private void setupRecyclerViews() {
         // Set up Drawer menu to select conversation
         chatAdapter = new ChatAdapter(chatList, this);
-        rvChatList.setLayoutManager(new LinearLayoutManager(getContext()));
-        rvChatList.setAdapter(chatAdapter);
+        binding.rvChatList.setLayoutManager(new LinearLayoutManager(getContext()));
+        binding.rvChatList.setAdapter(chatAdapter);
 
         // set up RecyclerView for selected chat to show messages
         messageAdapter = new MessageAdapter(messageList, null);
         LinearLayoutManager lm = new LinearLayoutManager(getContext());
         lm.setStackFromEnd(true);
-        rvMessages.setLayoutManager(lm);
-        rvMessages.setAdapter(messageAdapter);
+        binding.rvMessages.setLayoutManager(lm);
+        binding.rvMessages.setAdapter(messageAdapter);
         setConversationActive(false);
     }
 
-    //Helper function to load token and user id then connect to websocket
+    /**
+     * Loads authentication tokens and user info, then initializes the Stomp WebSocket connection.
+     */
     private void loadInitialData() {
-        TokenManager tm = TokenManager.getInstance(requireContext());
-        String token = tm.getToken();
-        currentUserId = tm.getUserId();
-        String role = tm.getRole();
+        String token = tokenManager.getToken();
+        currentUserId = tokenManager.getUserId();
+        String role = tokenManager.getRole();
 
         messageAdapter.setCurrentUserId(currentUserId);
+        messageAdapter.setToken(token);
 
         // if token exist then connect to websocket
         if (token != null) {
-            stompChatManager = new StompChatManager(token, role);
+            stompChatManager = new StompChatManager(token, role, baseUrl);
             stompChatManager.setMessageListener(this);
             stompChatManager.setConversationListener(this);
             stompChatManager.setConnectionListener(this);
@@ -126,89 +169,74 @@ public class ChatFragment extends Fragment implements ChatAdapter.OnChatClickLis
 
         if (getArguments() != null && getArguments().containsKey("conversation_id")) {
             activeConversationId = getArguments().getLong("conversation_id");
+        } else if (getActivity() != null && getActivity().getIntent().hasExtra("conversation_id")) {
+            activeConversationId = getActivity().getIntent().getLongExtra("conversation_id", -1);
+            getActivity().getIntent().removeExtra("conversation_id");
+            getActivity().getIntent().removeExtra("navigate_to");
         }
 
         loadCustomers();
     }
 
-    //Helper function to load customer names for it to be displayed on drawer menu
+    /**
+     * Fetches a list of customers from the ViewModel to display customer names for the chat list.
+     */
     private void loadCustomers() {
-        customerApi.getAllCustomers(0, 100).enqueue(new Callback<PageResponse<CustomerDTO>>() {
-            @Override
-            public void onResponse(@NonNull Call<PageResponse<CustomerDTO>> call,
-                                   @NonNull Response<PageResponse<CustomerDTO>> response) {
-                if (response.isSuccessful() && response.body() != null) {
-                    for (CustomerDTO c : response.body().getContent()) {
-                        customerNames.put(c.getCustomerId(), c.getFullName());
-                    }
-                }
-                loadConversations();
-            }
-
-            @Override
-            public void onFailure(@NonNull Call<PageResponse<CustomerDTO>> call,
-                                  @NonNull Throwable t) {
+        viewModel.getAllCustomers(0, 100).observe(getViewLifecycleOwner(), resource -> {
+            if (resource != null && resource.status == Resource.Status.SUCCESS && resource.data != null) {
+                resource.data.getContent().forEach(c -> customerNames.put(c.getCustomerId(), c.getFullName()));
                 loadConversations();
             }
         });
     }
 
-    //helper function to load conversations entities to display with customer names in drawer menu
+    /**
+     * Retrieves all conversations for the current user through the ViewModel and populates the chat drawer.
+     */
     private void loadConversations() {
-        chatApi.getAllConversations().enqueue(new Callback<List<ConversationDTO>>() {
-            @Override
-            public void onResponse(@NonNull Call<List<ConversationDTO>> call,
-                                   @NonNull Response<List<ConversationDTO>> response) {
-                if (response.isSuccessful() && response.body() != null) {
-                    chatList.clear();
-                    List<Chat> loaded = response.body().stream()
-                            .map(dto -> {
-                                String name = customerNames.getOrDefault(
-                                        dto.getCustomerId(), "Customer #" + dto.getCustomerId());
-                                return new Chat(String.valueOf(dto.getId()),
-                                        name, dto.getLastMessage(),
-                                        dto.getCustomerId(), dto.getStaffId());
-                            })
-                            .collect(Collectors.toList());
-                    chatList.addAll(loaded);
-                    chatAdapter.notifyDataSetChanged();
-                    
-                    if (activeConversationId != null) {
-                        setConversationActive(true);
-                        // Update title to customer name of active conversation
-                        for (Chat chat : chatList) {
-                            if (chat.getChatId().equals(String.valueOf(activeConversationId))) {
-                                tvChatTitle.setText(chat.getCustomerName());
-                                break;
-                            }
-                        }
-                        if (stompChatManager != null) {
-                            stompChatManager.subscribeToConversation(activeConversationId);
-                        }
-                        loadMessageHistory(activeConversationId);
-                    } else {
-                        messageList.clear();
-                        messageAdapter.notifyDataSetChanged();
-                        setConversationActive(false);
-                    }
+        viewModel.getAllConversations().observe(getViewLifecycleOwner(), resource -> {
+            if (resource != null && resource.status == Resource.Status.SUCCESS && resource.data != null) {
+                chatList.clear();
+                for (ConversationDTO dto : resource.data) {
+                    String name = customerNames.getOrDefault(
+                            dto.getCustomerId(), "Customer #" + dto.getCustomerId());
+                    chatList.add(new Chat(String.valueOf(dto.getId()),
+                            name, dto.getLastMessage(),
+                            dto.getCustomerId(), dto.getStaffId()));
+                }
+                chatAdapter.notifyDataSetChanged();
+
+                if (activeConversationId != null) {
+                    setConversationActive(true);
+                    // Update title to customer name of active conversation
+                    for (Chat chat : chatList) {
+                        if (chat.getChatId().equals(String.valueOf(activeConversationId))) {
+                            binding.tvChatTitle.setText(chat.getCustomerName());
+                            break;
+                        }
+                    }
+                    if (stompChatManager != null) {
+                        stompChatManager.subscribeToConversation(activeConversationId);
+                    }
+                    loadMessageHistory(activeConversationId);
+                } else {
+                    messageList.clear();
+                    messageAdapter.notifyDataSetChanged();
+                    setConversationActive(false);
                 }
-            }
-            @Override
-            public void onFailure(@NonNull Call<List<ConversationDTO>> call,
-                                  @NonNull Throwable t) {
-                Log.e(TAG, "Error loading conversations", t);
             }
         });
     }
 
-    // Called when user taps a chat in the drawer
-    // Loads messages for that chat selected
+    /**
+     * Handles selection of a chat from the drawer, updating the UI and subscribing to the WebSocket.
+     */
     @Override
     public void onChatClick(Chat chat) {
         activeConversationId = Long.parseLong(chat.getChatId());
         setConversationActive(true);
-        tvChatTitle.setText(chat.getCustomerName());
-        drawerLayout.closeDrawer(GravityCompat.START);
+        binding.tvChatTitle.setText(chat.getCustomerName());
+        binding.chatDrawerLayout.closeDrawer(GravityCompat.START);
 
         if (stompChatManager != null) {
             stompChatManager.subscribeToConversation(activeConversationId);
@@ -217,63 +245,127 @@ public class ChatFragment extends Fragment implements ChatAdapter.OnChatClickLis
         loadMessageHistory(activeConversationId);
     }
 
-    //helper function to load messages for selected chat
+    /**
+     * Fetches the full message history for a specific conversation from the ViewModel.
+     */
     private void loadMessageHistory(Long conversationId) {
-        messageApi.getMessages(conversationId).enqueue(new Callback<List<MessageDTO>>() {
-            @Override
-            public void onResponse(@NonNull Call<List<MessageDTO>> call,
-                                   @NonNull Response<List<MessageDTO>> response) {
-                if (response.isSuccessful() && response.body() != null) {
-                    messageList.clear();
-                    for (MessageDTO dto : response.body()) {
-                        messageList.add(dtoToModel(dto));
-                    }
-                    messageAdapter.notifyDataSetChanged();
-                    scrollToBottom();
+        viewModel.getMessages(conversationId).observe(getViewLifecycleOwner(), resource -> {
+            if (resource != null && resource.status == Resource.Status.SUCCESS && resource.data != null) {
+                messageList.clear();
+                for (MessageDTO dto : resource.data) {
+                    messageList.add(dtoToModel(dto));
                 }
-            }
-            @Override
-            public void onFailure(@NonNull Call<List<MessageDTO>> call,
-                                  @NonNull Throwable t) {
-                Log.e(TAG, "Error loading messages", t);
+                messageAdapter.notifyDataSetChanged();
+                scrollToBottom();
             }
         });
     }
 
-    //Helper function to send a message to the chat
+    /**
+     * Sends a plain text message to the currently active conversation through the ViewModel.
+     */
     private void sendMessage() {
         //check if a chat is selected
         if (activeConversationId == null) return;
 
         //get the message from text field
-        String text = etMessage.getText().toString().trim();
+        String text = binding.etMessage.getText().toString().trim();
         if (text.isEmpty()) return;
 
         //clear text field after sending
-        etMessage.setText("");
+        binding.etMessage.setText("");
 
-        //calls api to send the message
-        messageApi.sendMessage(activeConversationId, new SendMessageRequest(text))
-                .enqueue(new Callback<MessageDTO>() {
-                    @Override
-                    public void onResponse(@NonNull Call<MessageDTO> call,
-                                           @NonNull Response<MessageDTO> response) {
-                        if (response.isSuccessful() && response.body() != null) {
-                            messageList.add(dtoToModel(response.body()));
-                            messageAdapter.notifyItemInserted(messageList.size() - 1);
-                            scrollToBottom();
-                            loadConversations();
-                        }
-                    }
-                    @Override
-                    public void onFailure(@NonNull Call<MessageDTO> call,
-                                          @NonNull Throwable t) {
-                        Log.e(TAG, "Send failed", t);
-                    }
-                });
+        //calls viewmodel to send the message
+        viewModel.sendMessage(activeConversationId, new SendMessageRequest(text)).observe(getViewLifecycleOwner(), resource -> {
+            if (resource != null && resource.status == Resource.Status.SUCCESS && resource.data != null) {
+                messageList.add(dtoToModel(resource.data));
+                messageAdapter.notifyItemInserted(messageList.size() - 1);
+                scrollToBottom();
+                loadConversations();
+            }
+        });
     }
 
-    // When a message is received updates the chat preview
+    /**
+     * Launches a file picker intent to select an attachment for the message.
+     */
+    private void selectAttachment() {
+        Intent intent = new Intent(Intent.ACTION_GET_CONTENT);
+        intent.setType("*/*");
+        attachmentLauncher.launch(intent);
+    }
+
+    /**
+     * Displays a preview of the selected attachment in the UI.
+     */
+    private void showAttachmentPreview(Uri uri) {
+        pendingAttachmentUri = uri;
+        binding.layoutAttachmentPreview.setVisibility(View.VISIBLE);
+        
+        String mimeType = requireContext().getContentResolver().getType(uri);
+        String fileName = getFileName(uri);
+        binding.tvPreviewName.setText(fileName);
+
+        // If the file is an image, display a thumbnail of the image as well
+        if (mimeType != null && mimeType.startsWith("image/")) {
+            binding.ivPreview.setVisibility(View.VISIBLE);
+            Glide.with(this).load(uri).into(binding.ivPreview);
+        } else {
+            binding.ivPreview.setVisibility(View.GONE);
+        }
+    }
+
+    /**
+     * Clears the current attachment selection and hides the preview UI.
+     */
+    private void removeAttachment() {
+        pendingAttachmentUri = null;
+        binding.layoutAttachmentPreview.setVisibility(View.GONE);
+    }
+
+    /**
+     * Show the display name of the file from its Uri.
+     */
+    private String getFileName(Uri uri) {
+        String result = null;
+        if (uri.getScheme().equals("content")) {
+            try (Cursor cursor = requireContext().getContentResolver().query(uri, null, null, null, null)) {
+                if (cursor != null && cursor.moveToFirst()) {
+                    int index = cursor.getColumnIndex(OpenableColumns.DISPLAY_NAME);
+                    if (index != -1) {
+                        result = cursor.getString(index);
+                    }
+                }
+            }
+        }
+        if (result == null) {
+            result = uri.getPath();
+            int cut = result.lastIndexOf('/');
+            if (cut != -1) {
+                result = result.substring(cut + 1);
+            }
+        }
+        return result;
+    }
+
+    /**
+     * Handles sending a message that includes a file attachment via the ViewModel.
+     */
+    private void sendWithAttachment(Uri uri) {
+        if (activeConversationId == null) return;
+        String text = binding.etMessage.getText().toString().trim();
+        binding.etMessage.setText("");
+        removeAttachment();
+
+        if (!text.isEmpty()) {
+            binding.etMessage.setText(text);
+        }
+        Toast.makeText(requireContext(), "File attachments are not supported", Toast.LENGTH_SHORT).show();
+    }
+
+    /**
+     * Callback triggered when a new message is received via the WebSocket.
+     */
     @Override
     public void onMessageReceived(MessageDTO dto) {
         //if there is no active selected conversation or the message received is for another chat, then just update the preview of last message
@@ -287,81 +379,102 @@ public class ChatFragment extends Fragment implements ChatAdapter.OnChatClickLis
 
         //else add the message to the active chat if it's not from the current user
         messageList.add(dtoToModel(dto));
-        messageAdapter.notifyItemInserted(messageList.size() - 1);
-        scrollToBottom();
+        requireActivity().runOnUiThread(() -> {
+            messageAdapter.notifyItemInserted(messageList.size() - 1);
+            scrollToBottom();
+        });
     }
 
-    // When a new conversation is added, updates the chat preview
+    /**
+     * Callback triggered when a conversation is created or updated via the WebSocket.
+     */
     @Override
     public void onConversationUpdated(ConversationDTO dto) {
-        boolean updated = false;
-        String name = customerNames.getOrDefault(
-                dto.getCustomerId(), "Customer #" + dto.getCustomerId());
+        requireActivity().runOnUiThread(() -> {
+            boolean updated = false;
+            String name = customerNames.getOrDefault(
+                    dto.getCustomerId(), "Customer #" + dto.getCustomerId());
 
-        for (int i = 0; i < chatList.size(); i++) {
-            Chat existing = chatList.get(i);
-            if (existing.getChatId().equals(String.valueOf(dto.getId()))) {
-                chatList.set(i, new Chat(
+            for (int i = 0; i < chatList.size(); i++) {
+                Chat existing = chatList.get(i);
+                if (existing.getChatId().equals(String.valueOf(dto.getId()))) {
+                    chatList.set(i, new Chat(
+                            String.valueOf(dto.getId()),
+                            name,
+                            dto.getLastMessage(),
+                            dto.getCustomerId(),
+                            dto.getStaffId()
+                    ));
+                    chatAdapter.notifyItemChanged(i);
+                    updated = true;
+                    break;
+                }
+            }
+
+            if (!updated) {
+                chatList.add(0, new Chat(
                         String.valueOf(dto.getId()),
                         name,
                         dto.getLastMessage(),
                         dto.getCustomerId(),
                         dto.getStaffId()
                 ));
-                chatAdapter.notifyItemChanged(i);
-                updated = true;
-                break;
+                chatAdapter.notifyItemInserted(0);
             }
-        }
 
-        if (!updated) {
-            chatList.add(0, new Chat(
-                    String.valueOf(dto.getId()),
-                    name,
-                    dto.getLastMessage(),
-                    dto.getCustomerId(),
-                    dto.getStaffId()
-            ));
-            chatAdapter.notifyItemInserted(0);
-        }
-
-        if (activeConversationId != null && activeConversationId.equals(dto.getId())) {
-            setConversationActive(true);
-            tvChatTitle.setText(name);
-        }
+            if (activeConversationId != null && activeConversationId.equals(dto.getId())) {
+                setConversationActive(true);
+                binding.tvChatTitle.setText(name);
+            }
+        });
     }
 
+    /**
+     * Callback triggered when the WebSocket connection is successfully opened.
+     */
     @Override
     public void onSocketOpened() {
         if (!isAdded()) {
             return;
         }
-        loadConversations();
-        if (activeConversationId != null) {
-            loadMessageHistory(activeConversationId);
-        }
+        requireActivity().runOnUiThread(() -> {
+            loadConversations();
+            if (activeConversationId != null) {
+                loadMessageHistory(activeConversationId);
+            }
+        });
     }
 
+    /**
+     * Callback triggered when the WebSocket connection is closed.
+     */
     @Override
     public void onSocketClosed() {
         if (!isAdded()) {
             return;
         }
-        loadConversations();
+        requireActivity().runOnUiThread(this::loadConversations);
     }
 
+    /**
+     * Callback triggered when a WebSocket connection error occurs.
+     */
     @Override
     public void onSocketError() {
         if (!isAdded()) {
             return;
         }
-        loadConversations();
-        if (activeConversationId != null) {
-            loadMessageHistory(activeConversationId);
-        }
+        requireActivity().runOnUiThread(() -> {
+            loadConversations();
+            if (activeConversationId != null) {
+                loadMessageHistory(activeConversationId);
+            }
+        });
     }
 
-    // Helper function to convert DTO to message
+    /**
+     * Converts a MessageDTO into a Message object.
+     */
     private Message dtoToModel(MessageDTO dto) {
         Message m = new Message();
         m.setId(dto.getId());
@@ -370,64 +483,80 @@ public class ChatFragment extends Fragment implements ChatAdapter.OnChatClickLis
         m.setContent(dto.getContent());
         m.setTimestamp(dto.getTimestamp());
         m.setIsRead(dto.getIsRead());
+        m.setAttachmentUrl(dto.getAttachmentUrl());
+        m.setAttachmentName(dto.getAttachmentName());
+        m.setAttachmentType(dto.getAttachmentType());
         return m;
     }
 
-    //Helper function to scroll to bottom of the chat
+    /**
+     * Scrolls the message history RecyclerView to the most recent message.
+     */
     private void scrollToBottom() {
         if (!messageList.isEmpty()) {
-            rvMessages.post(() ->
-                    rvMessages.smoothScrollToPosition(messageList.size() - 1));
+            binding.rvMessages.post(() ->
+                    binding.rvMessages.smoothScrollToPosition(messageList.size() - 1));
         }
     }
 
-    // Helper function to update the chat preview last message
+    /**
+     * Updates the preview snippet of the last message for a specific conversation in the drawer.
+     */
     private void updateConversationPreview(Long conversationId, String lastMessage) {
         if (conversationId == null) {
             return;
         }
-        for (int i = 0; i < chatList.size(); i++) {
-            Chat existing = chatList.get(i);
-            if (existing.getChatId().equals(String.valueOf(conversationId))) {
-                Chat updated = new Chat(
-                        existing.getChatId(),
-                        existing.getCustomerName(),
-                        lastMessage,
-                        existing.getCustomerId(),
-                        existing.getStaffId()
-                );
-                chatList.set(i, updated);
-                chatAdapter.notifyItemChanged(i);
-                return;
+        requireActivity().runOnUiThread(() -> {
+            for (int i = 0; i < chatList.size(); i++) {
+                Chat existing = chatList.get(i);
+                if (existing.getChatId().equals(String.valueOf(conversationId))) {
+                    Chat updated = new Chat(
+                            existing.getChatId(),
+                            existing.getCustomerName(),
+                            lastMessage,
+                            existing.getCustomerId(),
+                            existing.getStaffId()
+                    );
+                    chatList.set(i, updated);
+                    chatAdapter.notifyItemChanged(i);
+                    return;
+                }
             }
-        }
+        });
     }
 
-    //Helper function to enable or disable the send button when there is no active chat
+    /**
+     * Toggles the UI state based on whether a conversation is currently selected.
+     */
     private void setConversationActive(boolean active) {
-        btnSend.setEnabled(active);
-        etMessage.setEnabled(active);
+        binding.btnSend.setEnabled(active);
+        binding.etMessage.setEnabled(active);
+        binding.btnAttach.setEnabled(active);
         if (!active) {
             activeConversationId = null;
             ChatNotificationService.activeConversationIdInUi = null;
-            if (tvChatTitle != null) tvChatTitle.setText("Customer Chat");
+            removeAttachment();
+            if (binding != null && binding.tvChatTitle != null) binding.tvChatTitle.setText("Customer Chat");
             if (stompChatManager != null) {
                 stompChatManager.clearConversationSubscription();
             }
             messageList.clear();
             messageAdapter.notifyDataSetChanged();
-            etMessage.setText("");
-            etMessage.setHint("Select a chat to start messaging");
+            binding.etMessage.setText("");
+            binding.etMessage.setHint("Select a chat to start messaging");
         } else {
-            etMessage.setHint("Type a message...");
+            binding.etMessage.setHint("Type a message...");
             ChatNotificationService.activeConversationIdInUi = activeConversationId;
         }
     }
 
-    // When fragment is destroyed, disconnect from websocket
+    /**
+     * Disconnects the WebSocket manager when the fragment view is destroyed.
+     */
     @Override
     public void onDestroyView() {
         super.onDestroyView();
+        binding = null;
         ChatNotificationService.activeConversationIdInUi = null;
         if (stompChatManager != null) stompChatManager.disconnect();
     }

android/app/src/main/java/com/example/petstoremobile/fragments/ListFragment.java

@@ -2,110 +2,74 @@ package com.example.petstoremobile.fragments;
 
 import android.os.Bundle;
 
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 import androidx.core.view.GravityCompat;
 import androidx.drawerlayout.widget.DrawerLayout;
 import androidx.fragment.app.Fragment;
+import androidx.navigation.NavController;
+import androidx.navigation.fragment.NavHostFragment;
 
 import android.view.LayoutInflater;
 
 import android.view.View;
 import android.view.ViewGroup;
-import android.widget.LinearLayout;
 
 import com.example.petstoremobile.R;
-
 import com.example.petstoremobile.api.auth.TokenManager;
-import com.example.petstoremobile.fragments.listfragments.PetFragment;
-import com.example.petstoremobile.fragments.listfragments.ServiceFragment;
-import com.example.petstoremobile.fragments.listfragments.StaffFragment;
-import com.example.petstoremobile.fragments.listfragments.SupplierFragment;
-import com.example.petstoremobile.fragments.listfragments.AdoptionFragment;
-import com.example.petstoremobile.fragments.listfragments.AppointmentFragment;
-import com.example.petstoremobile.fragments.listfragments.InventoryFragment;
-import com.example.petstoremobile.fragments.listfragments.ProductFragment;
-import com.example.petstoremobile.fragments.listfragments.ProductSupplierFragment;
-import com.example.petstoremobile.fragments.listfragments.PurchaseOrderFragment;
-import com.example.petstoremobile.fragments.listfragments.SaleFragment;
-import com.example.petstoremobile.fragments.listfragments.AnalyticsFragment;
+import com.example.petstoremobile.databinding.FragmentListBinding;
 
+import javax.inject.Inject;
+
+import dagger.hilt.android.AndroidEntryPoint;
 
 //The Fragment for the displaying the list of entities to be viewed
+@AndroidEntryPoint
 public class ListFragment extends Fragment {
 
-    private DrawerLayout drawerLayout;
-    private LinearLayout drawerPets, drawerServices, drawerSuppliers;
-    private View touchBlocker;
-
-    // Adoptions, Appointments, Inventory, Products
-
-    private LinearLayout drawerAdoptions, drawerAppointments, drawerInventory, drawerProducts, drawerProductSupplier, drawerPurchaseOrderView, drawerSale;
-
-    private LinearLayout drawerAnalytics;
-
-    //Staff
-
-    private LinearLayout drawerStaff;
+    private FragmentListBinding binding;
+    private NavController innerNavController;
 
+    @Inject TokenManager tokenManager;
 
+    /**
+     * Inflates the fragment layout, initializes navigation drawers, and applies role-based access control.
+     */
     @Override
-    public View onCreateView(LayoutInflater inflater, ViewGroup container,
+    public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
-        View view = inflater.inflate(R.layout.fragment_list, container, false);
-
-        //get controls from the layout
-        drawerLayout = view.findViewById(R.id.drawerLayout);
-        drawerPets = view.findViewById(R.id.drawerPets);
-        drawerServices = view.findViewById(R.id.drawerServices);
-        drawerSuppliers = view.findViewById(R.id.drawerSuppliers);
-        drawerAdoptions = view.findViewById(R.id.drawerAdoptions);
-        drawerAppointments = view.findViewById(R.id.drawerAppointments);
-        drawerInventory = view.findViewById(R.id.drawerInventory);
-        drawerProducts = view.findViewById(R.id.drawerProducts);
-        drawerProductSupplier=view.findViewById(R.id.drawerProductSupplier);
-        drawerSale=view.findViewById(R.id.drawerSale);
-        drawerAnalytics = view.findViewById(R.id.drawerAnalytics);
-        drawerPurchaseOrderView=view.findViewById(R.id.drawerPurchaseOrderView);
-        drawerStaff = view.findViewById(R.id.drawerStaff);
-
+        binding = FragmentListBinding.inflate(inflater, container, false);
 
         // Check user role and restrict access for STAFF
-        String role = TokenManager.getInstance(requireContext()).getRole();
+        String role = tokenManager.getRole();
         if ("STAFF".equalsIgnoreCase(role)) {
-            drawerSuppliers.setVisibility(View.GONE);
-            drawerInventory.setVisibility(View.GONE);
-        }
-
-        //needed to disable touches on the innerContainer while the drawer is open
-        touchBlocker = view.findViewById(R.id.touchBlocker);
-
-        //Display pets fragment by default
-        if (savedInstanceState == null) {
-            loadFragment(new PetFragment());
+            binding.drawerSuppliers.setVisibility(View.GONE);
+            binding.drawerInventory.setVisibility(View.GONE);
         }
 
         // Only show for ADMIN
         if ("ADMIN".equalsIgnoreCase(role)) {
-            drawerStaff.setVisibility(View.VISIBLE);
+            binding.drawerStaff.setVisibility(View.VISIBLE);
         } else {
-            drawerStaff.setVisibility(View.GONE);
+            binding.drawerStaff.setVisibility(View.GONE);
         }
 
         //add Listeners to the drawer so user won't be able to interact with the innerContainer (the list fragments)
         //while the drawer is open
-        drawerLayout.addDrawerListener(new DrawerLayout.DrawerListener() {
+        binding.drawerLayout.addDrawerListener(new DrawerLayout.DrawerListener() {
 
             //When the drawer is opened, disable touches on the background
             @Override
             public void onDrawerOpened(View drawerView) {
-                touchBlocker.setVisibility(View.VISIBLE);
-                touchBlocker.setClickable(true);
+                binding.touchBlocker.setVisibility(View.VISIBLE);
+                binding.touchBlocker.setClickable(true);
             }
 
             //When the drawer is closed, enable touches again
             @Override
             public void onDrawerClosed(View drawerView) {
-                touchBlocker.setVisibility(View.GONE);
-                touchBlocker.setClickable(false);
+                binding.touchBlocker.setVisibility(View.GONE);
+                binding.touchBlocker.setClickable(false);
             }
 
             //unused methods
@@ -116,99 +80,55 @@ public class ListFragment extends Fragment {
         });
 
         // Click listeners for each drawer
-        //Pets
-        drawerPets.setOnClickListener(v -> {
-            loadFragment(new PetFragment());
-            drawerLayout.closeDrawers();
-        });
+        binding.drawerPets.setOnClickListener(v -> navigateTo(R.id.nav_pet));
+        binding.drawerServices.setOnClickListener(v -> navigateTo(R.id.nav_service));
+        binding.drawerSuppliers.setOnClickListener(v -> navigateTo(R.id.nav_supplier));
+        binding.drawerAdoptions.setOnClickListener(v -> navigateTo(R.id.nav_adoption));
+        binding.drawerAppointments.setOnClickListener(v -> navigateTo(R.id.nav_appointment));
+        binding.drawerInventory.setOnClickListener(v -> navigateTo(R.id.nav_inventory));
+        binding.drawerProducts.setOnClickListener(v -> navigateTo(R.id.nav_product));
+        binding.drawerProductSupplier.setOnClickListener(v -> navigateTo(R.id.nav_product_supplier));
+        binding.drawerPurchaseOrderView.setOnClickListener(v -> navigateTo(R.id.nav_purchase_order));
+        binding.drawerSale.setOnClickListener(v -> navigateTo(R.id.nav_sale));
+        binding.drawerStaff.setOnClickListener(v -> navigateTo(R.id.nav_staff));
+        binding.drawerAnalytics.setOnClickListener(v -> navigateTo(R.id.nav_analytics));
 
-        //Services
-        drawerServices.setOnClickListener(v -> {
-            loadFragment(new ServiceFragment());
-            drawerLayout.closeDrawers();
-        });
-
-        //Suppliers
-        drawerSuppliers.setOnClickListener(v -> {
-            loadFragment(new SupplierFragment());
-            drawerLayout.closeDrawers();
-        });
-
-        //Adoptions
-
-        drawerAdoptions.setOnClickListener(v -> {
-            loadFragment(new AdoptionFragment());
-            drawerLayout.closeDrawers();
-        });
-
-        //Appointment
-        drawerAppointments.setOnClickListener(v -> {
-            loadFragment(new AppointmentFragment());
-            drawerLayout.closeDrawers();
-        });
-
-        //Inventory
-        drawerInventory.setOnClickListener(v -> {
-            loadFragment(new InventoryFragment());
-            drawerLayout.closeDrawers();
-        });
-
-        //Products
-        drawerProducts.setOnClickListener(v -> {
-            loadFragment(new ProductFragment());
-            drawerLayout.closeDrawers();
-        });
-
-        //ProductSupplier
-
-        drawerProductSupplier.setOnClickListener(v -> {
-            loadFragment(new ProductSupplierFragment());
-            drawerLayout.closeDrawers();
-        });
-
-        //Purchase
-
-        drawerPurchaseOrderView.setOnClickListener(v -> {
-            loadFragment(new PurchaseOrderFragment());
-            drawerLayout.closeDrawers();
-        });
-
-        //Sale
-
-        drawerSale.setOnClickListener(v -> {
-            loadFragment(new SaleFragment());
-            drawerLayout.closeDrawers();
-        });
-
-        //Analytics
-
-        drawerAnalytics.setOnClickListener(v -> {
-            loadFragment(new AnalyticsFragment());
-            drawerLayout.closeDrawers();
-        });
-
-        // Click listener
-        drawerStaff.setOnClickListener(v -> {
-            loadFragment(new StaffFragment());
-            drawerLayout.closeDrawers();
-        });
-
-
-
-        return view;
+        return binding.getRoot();
     }
 
-    //helper function to open the drawer
+    @Override
+    public void onDestroyView() {
+        super.onDestroyView();
+        binding = null;
+    }
+
+    /**
+     * Initializes the NavController for the internal fragment container.
+     */
+    @Override
+    public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
+        super.onViewCreated(view, savedInstanceState);
+        NavHostFragment navHostFragment = (NavHostFragment) getChildFragmentManager()
+                .findFragmentById(R.id.inner_nav_host_fragment);
+        if (navHostFragment != null) {
+            innerNavController = navHostFragment.getNavController();
+        }
+    }
+
+    /**
+     * Navigates to a specific inner destination and closes all drawers.
+     */
+    private void navigateTo(int destinationId) {
+        if (innerNavController != null) {
+            innerNavController.navigate(destinationId);
+        }
+        binding.drawerLayout.closeDrawers();
+    }
+
+    /**
+     * Programmatically opens the navigation drawer.
+     */
     public void openDrawer() {
-        drawerLayout.openDrawer(GravityCompat.START);
-    }
-
-    // helper function to load the fragment into the display
-    public void loadFragment(Fragment fragment) {
-        getChildFragmentManager()
-                .beginTransaction()
-                .replace(R.id.inner_fragment_container, fragment)
-                .addToBackStack(null)
-                .commit();
+        binding.drawerLayout.openDrawer(GravityCompat.START);
     }
 }

android/app/src/main/java/com/example/petstoremobile/fragments/ProfileFragment.java

@@ -1,186 +1,109 @@
 package com.example.petstoremobile.fragments;
 
-import android.Manifest;
-import android.app.Activity;
-import android.content.Intent;
-import android.content.pm.PackageManager;
 import android.net.Uri;
 import android.os.Bundle;
 
-import androidx.activity.result.ActivityResultLauncher;
-import androidx.activity.result.contract.ActivityResultContracts;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 import androidx.appcompat.app.AlertDialog;
-import androidx.core.content.ContextCompat;
-import androidx.core.content.FileProvider;
 import androidx.fragment.app.Fragment;
+import androidx.lifecycle.ViewModelProvider;
 
-import android.provider.MediaStore;
-import android.text.InputType;
 import android.util.Log;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
-import android.widget.Button;
 import android.widget.EditText;
-import android.widget.ImageView;
-import android.widget.TextView;
 import android.widget.Toast;
 
-import com.bumptech.glide.Glide;
-import com.bumptech.glide.load.engine.DiskCacheStrategy;
-import com.bumptech.glide.load.model.GlideUrl;
-import com.bumptech.glide.load.model.LazyHeaders;
 import com.example.petstoremobile.R;
 import com.example.petstoremobile.activities.MainActivity;
-import com.example.petstoremobile.api.RetrofitClient;
 import com.example.petstoremobile.api.auth.AuthApi;
 import com.example.petstoremobile.api.auth.TokenManager;
-import com.example.petstoremobile.dtos.ErrorResponse;
+import com.example.petstoremobile.databinding.FragmentProfileBinding;
 import com.example.petstoremobile.dtos.UserDTO;
 import com.example.petstoremobile.services.ChatNotificationService;
+import com.example.petstoremobile.utils.FileUtils;
+import com.example.petstoremobile.utils.GlideUtils;
+import com.example.petstoremobile.utils.ImagePickerHelper;
 import com.example.petstoremobile.utils.InputValidator;
-import com.google.gson.Gson;
+import com.example.petstoremobile.utils.Resource;
+import com.example.petstoremobile.utils.UIUtils;
+import com.example.petstoremobile.viewmodels.AuthViewModel;
 
 import java.io.File;
-import java.io.FileOutputStream;
-import java.io.InputStream;
 import java.util.HashMap;
 import java.util.Map;
 
+import javax.inject.Inject;
+import javax.inject.Named;
+
+import dagger.hilt.android.AndroidEntryPoint;
 import okhttp3.MediaType;
 import okhttp3.MultipartBody;
 import okhttp3.RequestBody;
-import retrofit2.Call;
-import retrofit2.Callback;
-import retrofit2.Response;
 
+/**
+ * Fragment that displays and allows editing of the user's profile information.
+ */
+@AndroidEntryPoint
 public class ProfileFragment extends Fragment {
 
-    //initialize the view/controls
-    private ImageView imgProfile;
-    private TextView tvProfileName, tvProfileEmail, tvProfilePhone, tvProfileRole;
-    private Uri photoUri;
+    private FragmentProfileBinding binding;
     private UserDTO currentUser;
+    private AuthViewModel viewModel;
+    private boolean hasImage = false;
 
-    //Initialize the launchers for camera and gallery
-    private ActivityResultLauncher<Intent> galleryLauncher;
-    private ActivityResultLauncher<Uri> cameraLauncher;
-    private ActivityResultLauncher<String> permissionLauncher;
+    @Inject TokenManager tokenManager;
+    @Inject @Named("baseUrl") String baseUrl;
 
-    //Called when the fragment is created, sets up the launchers is set profile image
+    private ImagePickerHelper imagePickerHelper;
+
+    /**
+     * Initializes activity launchers and the ImagePickerHelper for camera and gallary.
+     */
     @Override
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
+        viewModel = new ViewModelProvider(this).get(AuthViewModel.class);
 
-        // Launcher to open gallery to select profile image
-        galleryLauncher = registerForActivityResult(
-                //open gallery
-                new ActivityResultContracts.StartActivityForResult(),
-                result -> {
-                    //if the user selects an image and its not null
-                    if (result.getResultCode() == Activity.RESULT_OK
-                            && result.getData() != null) {
-                        //get the selected image and set the image to the profile
-                        Uri selectedImage = result.getData().getData();
-                        uploadAvatar(selectedImage);
-                    }
-                }
-        );
+        imagePickerHelper = new ImagePickerHelper(this, "profile_photo.jpg", new ImagePickerHelper.ImagePickerListener() {
+            @Override
+            public void onImagePicked(Uri uri) {
+                uploadAvatar(uri);
+            }
 
-        // Launcher for camera to open and capture profile image
-        cameraLauncher = registerForActivityResult(
-                //open camera
-                new ActivityResultContracts.TakePicture(),
-                success -> {
-                    //if a photo is taken set the image profile to it otherwise do nothing
-                    if (success) {
-                        uploadAvatar(photoUri);
-                    }
-                }
-        );
-
-        // Launcher to request camera permission
-        permissionLauncher = registerForActivityResult(
-                //ask user for camera permission
-                new ActivityResultContracts.RequestPermission(),
-                granted -> {
-                    //if the permission is granted launch the camera
-                    if (granted) {
-                        launchCamera();
-                    }
-                    else {
-                        //if the permission is denied then tell the user to grant it
-                        new AlertDialog.Builder(requireContext())
-                                .setTitle("Permission Permission Required")
-                                .setMessage("Please grant camera permission to use this feature")
-                                .setPositiveButton("Open Settings", (dialog, which) ->{
-                                    //open the settings page to grant the permission when they click open settings
-                                    Intent intent = new Intent(android.provider.Settings.ACTION_APPLICATION_DETAILS_SETTINGS);
-                                    intent.setData(Uri.fromParts("package", requireContext().getPackageName(), null));
-                                    startActivity(intent);
-                                })
-                                //close the dialog when the user clicks cancel
-                                .setNegativeButton("Cancel", null)
-                                .show();
-                    }
-                }
-        );
+            @Override
+            public void onImageRemoved() {
+                deleteAvatar();
+            }
+        });
     }
 
+    /**
+     * Inflates the fragment layout and sets up listeners for profile.
+     */
     @Override
-    public View onCreateView(LayoutInflater inflater, ViewGroup container,
+    public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
-        View view = inflater.inflate(R.layout.fragment_profile, container, false);
-
-        //get all the controls from the view
-        imgProfile = view.findViewById(R.id.imgProfile);
-        tvProfileName = view.findViewById(R.id.tvProfileName);
-        tvProfileEmail = view.findViewById(R.id.tvProfileEmail);
-        tvProfilePhone = view.findViewById(R.id.tvProfilePhone);
-        tvProfileRole = view.findViewById(R.id.tvProfileRole);
-        Button btnChangePhoto = view.findViewById(R.id.btnChangePhoto);
-        Button btnEditEmail = view.findViewById(R.id.btnEditEmail);
-        Button btnEditPhone = view.findViewById(R.id.btnEditPhone);
-        Button btnLogout = view.findViewById(R.id.btnLogout);
+        binding = FragmentProfileBinding.inflate(inflater, container, false);
 
         //Load Profile Data from backend
         loadProfileData();
 
         //Set up listeners for the buttons
         //Change photo button
-        btnChangePhoto.setOnClickListener(v -> {
-            //Show alert dialog to user to select from gallery or camera
-            new AlertDialog.Builder(requireContext())
-                    .setTitle("Change Profile Photo")
-                    //set the options for the alert dialog
-                    .setItems(new String[]{"Take Photo", "Choose from Gallery"}, (dialog, which) -> {
-                        if (which == 0) {
-                            // Choose Camera
-                            //Checks if the user has granted the camera permission already
-                            if (ContextCompat.checkSelfPermission(requireContext(), Manifest.permission.CAMERA) == PackageManager.PERMISSION_GRANTED) {
-                                //if the permission is already granted then launch the camera
-                                launchCamera();
-                            } else {
-                                //otherwise request the permission
-                                permissionLauncher.launch(Manifest.permission.CAMERA);
-                            }
-                        } else {
-                            // Choose Gallery
-                            Intent intent = new Intent(Intent.ACTION_PICK,
-                                    MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
-                            galleryLauncher.launch(intent);
-                        }
-                    })
-                    .show();
+        binding.btnChangePhoto.setOnClickListener(v -> {
+            imagePickerHelper.showImagePickerDialog("Change Profile Photo", hasImage);
         });
 
         //Edit email button
         //When clicked open a dialog to change email
-        btnEditEmail.setOnClickListener(v -> {
+        binding.btnEditEmail.setOnClickListener(v -> {
             //Make a text field for the user to enter the new email
             EditText input = new EditText(requireContext());
             input.setPadding(30,30,30,30);
-            input.setText(tvProfileEmail.getText().toString());
+            input.setText(binding.tvProfileEmail.getText().toString());
 
             //set input type to email
             input.setInputType(android.text.InputType.TYPE_TEXT_VARIATION_EMAIL_ADDRESS);
@@ -203,18 +126,17 @@ public class ProfileFragment extends Fragment {
 
         //Edit phone button
         //When clicked open a dialog to change phone
-        btnEditPhone.setOnClickListener(v -> {
+        binding.btnEditPhone.setOnClickListener(v -> {
             //Make a text field for the user to enter the new email
             EditText input = new EditText(requireContext());
             input.setPadding(30,30,30,30);
-            input.setText(tvProfilePhone.getText().toString());
+            input.setText(binding.tvProfilePhone.getText().toString());
 
             //set input type to phone number
-            input.setInputType(InputType.TYPE_CLASS_PHONE);
+            input.setInputType(android.view.inputmethod.EditorInfo.TYPE_CLASS_PHONE);
 
-            //add canada phone number formatting to input (XXX) XXX-XXXX
-            input.addTextChangedListener(new android.telephony.PhoneNumberFormattingTextWatcher("CA"));
-            input.setFilters(new android.text.InputFilter[]{new android.text.InputFilter.LengthFilter(14)});
+            //add canada phone number formatting to input
+            UIUtils.formatPhoneInput(input);
 
 
             //Show alert dialog to user to enter new phone
@@ -233,93 +155,71 @@ public class ProfileFragment extends Fragment {
         });
 
         //Logout button
-        btnLogout.setOnClickListener(v -> {
+        binding.btnLogout.setOnClickListener(v -> {
             // Stop notification service before logging out so notifications stop
-            Intent serviceIntent = new Intent(requireContext(), ChatNotificationService.class);
+            android.content.Intent serviceIntent = new android.content.Intent(requireContext(), ChatNotificationService.class);
             requireContext().stopService(serviceIntent);
 
-            TokenManager.getInstance(requireContext()).clearLoginData(); // clear the token for next login
+            tokenManager.clearLoginData(); // clear the token for next login
             //get the intent to the main activity and clear the back stack so the back button won't allow the user to go back to the previous screen
-            Intent intent = new Intent(getActivity(), MainActivity.class);
-            intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_NEW_TASK);
+            android.content.Intent intent = new android.content.Intent(getActivity(), MainActivity.class);
+            intent.addFlags(android.content.Intent.FLAG_ACTIVITY_CLEAR_TOP | android.content.Intent.FLAG_ACTIVITY_NEW_TASK);
             //start the activity to go to login page and finish the current activity
             startActivity(intent);
             requireActivity().finish();
         });
 
-        return view;
+        return binding.getRoot();
     }
 
-    //Helper function create a file in the cache directory to store the photo in then launch the camera to capture the photo
-    private void launchCamera() {
-        //create a file in the cache directory to store the photo in
-        File photoFile = new File(requireContext().getCacheDir(), "profile_photo.jpg");
-        //get the uri for the file made
-        photoUri = FileProvider.getUriForFile(requireContext(), requireContext().getPackageName() + ".fileprovider", photoFile);
-        //launch the camera to capture the photo and save the photo to photoUri
-        cameraLauncher.launch(photoUri);
+    @Override
+    public void onDestroyView() {
+        super.onDestroyView();
+        binding = null;
     }
 
-    //Helper function to call the backend to get profile data and load it to the view
+    /**
+     * Fetches current user profile data from the API and then updates the UI.
+     */
     private void loadProfileData() {
-        AuthApi authApi = RetrofitClient.getAuthApi(requireContext());
+        viewModel.getMe().observe(getViewLifecycleOwner(), resource -> {
+            if (resource == null) return;
+            if (resource.status == Resource.Status.SUCCESS && resource.data != null) {
+                currentUser = resource.data;
 
-        authApi.getMe().enqueue(new Callback<UserDTO>() {
-            @Override
-            public void onResponse(Call<UserDTO> call, Response<UserDTO> response) {
-                //if the response is successful and the body is not null then set the user to the view
-                if (response.isSuccessful() && response.body() != null) {
-                    currentUser = response.body();
+                //set the user data to the view
+                binding.tvProfileName.setText(currentUser.getFullName());
+                binding.tvProfileEmail.setText(currentUser.getEmail());
+                binding.tvProfilePhone.setText(currentUser.getPhone());
+                binding.tvProfileRole.setText(currentUser.getRole());
 
-                    //set the user data to the view
-                    tvProfileName.setText(currentUser.getFullName());
-                    tvProfileEmail.setText(currentUser.getEmail());
-                    tvProfilePhone.setText(currentUser.getPhone());
-                    tvProfileRole.setText(currentUser.getRole());
+                // get the avatar endpoint to load profile image and the token for authorization
+                String avatarUrl = baseUrl + AuthApi.AVATAR_FILE_PATH;
+                String token = tokenManager.getToken();
 
-                    // get the avatar endpoint to load profile image and the token for authorization
-                    String avatarUrl = RetrofitClient.BASE_URL + AuthApi.AVATAR_FILE_PATH;
-                    String token = TokenManager.getInstance(requireContext()).getToken();
-
-                    if (token != null) {
-                        // Create GlideUrl with token to fetch the image
-                        GlideUrl glideUrl = new GlideUrl(avatarUrl, new LazyHeaders.Builder()
-                                .addHeader("Authorization", "Bearer " + token)
-                                .build());
-
-                        // Load image using Glide
-                        Glide.with(ProfileFragment.this)
-                                .load(glideUrl)
-                                .diskCacheStrategy(DiskCacheStrategy.NONE)
-                                .skipMemoryCache(true)
-                                .placeholder(R.drawable.placeholder)
-                                .error(R.drawable.placeholder)
-                                .into(imgProfile);
-                    } else {
-                        // load placeholder image if token is null
-                        Glide.with(ProfileFragment.this)
-                                .load(R.drawable.placeholder)
-                                .into(imgProfile);
+                GlideUtils.loadImageWithToken(requireContext(), binding.imgProfile, avatarUrl, token, R.drawable.placeholder, new GlideUtils.ImageLoadListener() {
+                    @Override
+                    public void onResourceReady() {
+                        hasImage = true;
                     }
-                }
-                else {
-                    Log.e("onResponse: ", response.message());
-                    Toast.makeText(getContext(), "Failed to load profile: ", Toast.LENGTH_SHORT).show();
-                }
-            }
 
-            @Override
-            public void onFailure(Call<UserDTO> call, Throwable t) {
-                Log.e("PROFILE", "onFailure: " + t.getMessage());
-                Toast.makeText(getContext(), "Network error: could not load profile", Toast.LENGTH_SHORT).show();
+                    @Override
+                    public void onLoadFailed() {
+                        hasImage = false;
+                    }
+                });
+            } else if (resource.status == Resource.Status.ERROR) {
+                Toast.makeText(getContext(), "Failed to load profile: " + resource.message, Toast.LENGTH_SHORT).show();
             }
         });
     }
 
-    //Helper function to call the backend to upload a profile image
+    /**
+     * Uploads the selected or captured image as the user's new avatar.
+     */
     private void uploadAvatar(Uri uri) {
         try {
-            File file = getFileFromUri(uri);
+            File file = FileUtils.getFileFromUri(requireContext(), uri);
             if (file == null) return;
             
             // Create RequestBody for file upload
@@ -327,24 +227,13 @@ public class ProfileFragment extends Fragment {
             MultipartBody.Part body = MultipartBody.Part.createFormData("avatar", file.getName(), requestFile);
 
             //Call the backend to upload the avatar
-            AuthApi authApi = RetrofitClient.getAuthApi(requireContext());
-            authApi.uploadAvatar(body).enqueue(new Callback<UserDTO>() {
-                @Override
-                public void onResponse(Call<UserDTO> call, Response<UserDTO> response) {
-                    if (response.isSuccessful() && response.body() != null) {
-                        currentUser = response.body();
-                        Toast.makeText(requireContext(), "Avatar updated successfully", Toast.LENGTH_SHORT).show();
-                        // Reload image after successful upload
-                        loadProfileData();
-                    } else {
-                        Toast.makeText(requireContext(), "Failed to upload avatar", Toast.LENGTH_SHORT).show();
-                    }
-                }
-
-                @Override
-                public void onFailure(Call<UserDTO> call, Throwable t) {
-                    Log.e("UPLOAD_AVATAR", "Failure: " + t.getMessage());
-                    Toast.makeText(requireContext(), "Network error", Toast.LENGTH_SHORT).show();
+            viewModel.uploadAvatar(body).observe(getViewLifecycleOwner(), resource -> {
+                if (resource == null) return;
+                if (resource.status == Resource.Status.SUCCESS) {
+                    Toast.makeText(getContext(), "Avatar updated successfully", Toast.LENGTH_SHORT).show();
+                    loadProfileData();
+                } else if (resource.status == Resource.Status.ERROR) {
+                    Toast.makeText(getContext(), "Upload failed: " + resource.message, Toast.LENGTH_SHORT).show();
                 }
             });
         } catch (Exception e) {
@@ -352,58 +241,39 @@ public class ProfileFragment extends Fragment {
         }
     }
 
-    // Helper function to create a temporary File object from a Uri for uploading the avatar
-    private File getFileFromUri(Uri uri) {
-        try {
-            InputStream inputStream = requireContext().getContentResolver().openInputStream(uri);
-            File tempFile = new File(requireContext().getCacheDir(), "upload_avatar.jpg");
-            FileOutputStream outputStream = new FileOutputStream(tempFile);
-            byte[] buffer = new byte[1024];
-            int length;
-            while ((length = inputStream.read(buffer)) > 0) {
-                outputStream.write(buffer, 0, length);
+    /**
+     * Sends a request to the API to delete the current user's avatar image.
+     */
+    private void deleteAvatar() {
+        viewModel.deleteAvatar().observe(getViewLifecycleOwner(), resource -> {
+            if (resource == null) return;
+            if (resource.status == Resource.Status.SUCCESS) {
+                hasImage = false;
+                binding.imgProfile.setImageResource(R.drawable.placeholder);
+                Toast.makeText(getContext(), "Avatar removed successfully", Toast.LENGTH_SHORT).show();
+            } else if (resource.status == Resource.Status.ERROR) {
+                Toast.makeText(getContext(), "Removal failed: " + resource.message, Toast.LENGTH_SHORT).show();
             }
-            outputStream.close();
-            inputStream.close();
-            return tempFile;
-        } catch (Exception e) {
-            Log.e("FILE_UTILS", "Error creating temp file", e);
-            return null;
-        }
+        });
     }
 
-    //Helper function to update a profile field in the backend
+    /**
+     * Updates a specific profile field (like email or phone) by sending a request to the API.
+     */
     private void updateProfileField(String fieldName, String value) {
-        AuthApi authApi = RetrofitClient.getAuthApi(requireContext());
         Map<String, String> updates = new HashMap<>();
         updates.put(fieldName, value);
 
-        authApi.updateMe(updates).enqueue(new Callback<UserDTO>() {
-            @Override
-            public void onResponse(Call<UserDTO> call, Response<UserDTO> response) {
-                if (response.isSuccessful() && response.body() != null) {
-                    currentUser = response.body();
-                    // Update the view with the new data from backend
-                    tvProfileEmail.setText(currentUser.getEmail());
-                    tvProfilePhone.setText(currentUser.getPhone());
-                    Toast.makeText(requireContext(), "Profile updated successfully", Toast.LENGTH_SHORT).show();
-                } else {
-                    try {
-                        String errorJson = response.errorBody().string();
-                        ErrorResponse errorResponse = new Gson().fromJson(errorJson, ErrorResponse.class);
-                        String errorMessage = errorResponse.getMessage();
-                        Toast.makeText(requireContext(), errorMessage, Toast.LENGTH_LONG).show();
-                    } catch (Exception e) {
-                        Log.e("UPDATE_PROFILE", "Error parsing error body", e);
-                        Toast.makeText(requireContext(), "Failed to update profile", Toast.LENGTH_SHORT).show();
-                    }
-                }
-            }
-
-            @Override
-            public void onFailure(Call<UserDTO> call, Throwable t) {
-                Log.e("UPDATE_PROFILE", "Failure: " + t.getMessage());
-                Toast.makeText(requireContext(), "Network error", Toast.LENGTH_SHORT).show();
+        viewModel.updateMe(updates).observe(getViewLifecycleOwner(), resource -> {
+            if (resource == null) return;
+            if (resource.status == Resource.Status.SUCCESS && resource.data != null) {
+                currentUser = resource.data;
+                Toast.makeText(getContext(), "Profile updated successfully", Toast.LENGTH_SHORT).show();
+                // Update the view with the new data from backend
+                binding.tvProfileEmail.setText(currentUser.getEmail());
+                binding.tvProfilePhone.setText(currentUser.getPhone());
+            } else if (resource.status == Resource.Status.ERROR) {
+                Toast.makeText(getContext(), "Update failed: " + resource.message, Toast.LENGTH_SHORT).show();
             }
         });
     }

android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/AppointmentFragment.java

@@ -1,259 +1,374 @@
 package com.example.petstoremobile.fragments.listfragments;
 
+import android.graphics.Color;
 import android.os.Bundle;
 
 import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 import androidx.fragment.app.Fragment;
+import androidx.lifecycle.ViewModelProvider;
+import androidx.navigation.fragment.NavHostFragment;
 import androidx.recyclerview.widget.LinearLayoutManager;
-import androidx.recyclerview.widget.RecyclerView;
-import androidx.swiperefreshlayout.widget.SwipeRefreshLayout;
+
 import android.text.Editable;
 import android.text.TextWatcher;
 import android.util.Log;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
-import android.widget.EditText;
-import android.widget.ImageButton;
 import android.widget.Toast;
 
 import com.example.petstoremobile.R;
 import com.example.petstoremobile.adapters.AppointmentAdapter;
-import com.example.petstoremobile.api.AppointmentApi;
-import com.example.petstoremobile.api.PetApi;
-import com.example.petstoremobile.api.ServiceApi;
-import com.example.petstoremobile.api.RetrofitClient;
+import com.example.petstoremobile.databinding.FragmentAppointmentBinding;
 import com.example.petstoremobile.dtos.AppointmentDTO;
-import com.example.petstoremobile.dtos.ServiceDTO;
-import com.example.petstoremobile.dtos.PageResponse;
-import com.example.petstoremobile.dtos.PetDTO;
+import com.example.petstoremobile.dtos.StoreDTO;
 import com.example.petstoremobile.fragments.ListFragment;
-import com.example.petstoremobile.fragments.listfragments.detailfragments.AppointmentDetailFragment;
-import com.google.android.material.floatingactionbutton.FloatingActionButton;
+import com.example.petstoremobile.utils.BulkDeleteHandler;
+import com.example.petstoremobile.utils.Resource;
+import com.example.petstoremobile.utils.SpinnerUtils;
+import com.example.petstoremobile.viewmodels.AppointmentViewModel;
+import com.example.petstoremobile.utils.EventDecorator;
+import com.example.petstoremobile.viewmodels.AuthViewModel;
+import com.example.petstoremobile.viewmodels.StoreViewModel;
+import com.prolificinteractive.materialcalendarview.CalendarDay;
+import com.prolificinteractive.materialcalendarview.CalendarMode;
 
+import java.text.ParseException;
+import java.text.SimpleDateFormat;
 import java.util.ArrayList;
+import java.util.Calendar;
+import java.util.Date;
+import java.util.HashSet;
 import java.util.List;
+import java.util.Locale;
 
-import retrofit2.Call;
-import retrofit2.Callback;
-import retrofit2.Response;
+import dagger.hilt.android.AndroidEntryPoint;
 
+@AndroidEntryPoint
 public class AppointmentFragment extends Fragment implements AppointmentAdapter.OnAppointmentClickListener {
 
+    private FragmentAppointmentBinding binding;
     private List<AppointmentDTO> appointmentList = new ArrayList<>();
-    private List<AppointmentDTO> filteredList = new ArrayList<>();
-    private List<PetDTO> petList = new ArrayList<>();
-    private List<ServiceDTO> serviceList = new ArrayList<>();
+    private List<StoreDTO> storeList = new ArrayList<>();
 
     private AppointmentAdapter adapter;
-    private AppointmentApi api;
-    private SwipeRefreshLayout swipeRefreshLayout;
-    private EditText etSearch;
-    private ImageButton hamburger;
+    private AppointmentViewModel appointmentViewModel;
+    private StoreViewModel storeViewModel;
+    private AuthViewModel authViewModel;
+    private BulkDeleteHandler bulkDeleteHandler;
 
+    private CalendarDay selectedCalendarDay;
+    private boolean isMonthMode = false;
+    private Long currentUserId = null;
+    private final SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd", Locale.getDefault());
+
+    /**
+     * Initializes the fragment and its associated ViewModels.
+     */
     @Override
-    public View onCreateView(LayoutInflater inflater, ViewGroup container,
+    public void onCreate(@Nullable Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        appointmentViewModel = new ViewModelProvider(this).get(AppointmentViewModel.class);
+        storeViewModel = new ViewModelProvider(this).get(StoreViewModel.class);
+        authViewModel = new ViewModelProvider(this).get(AuthViewModel.class);
+    }
+
+    /**
+     * Sets up the fragment's UI, including RecyclerView, search, swipe-to-refresh, and calendar.
+     */
+    @Override
+    public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
-        View view = inflater.inflate(R.layout.fragment_appointment, container, false);
+        binding = FragmentAppointmentBinding.inflate(inflater, container, false);
 
-        api = RetrofitClient.getAppointmentApi(requireContext());
-        hamburger = view.findViewById(R.id.btnHamburger);
+        setupRecyclerView();
+        setupSearch();
+        setupStatusFilter();
+        setupStoreFilter();
+        setupSwipeRefresh();
+        setupCalendar();
+        setupFilterToggle();
+        setupMyAppointmentFilter();
+        setupBulkDelete();
 
-        setupRecyclerView(view);
-        setupSearch(view);
-        setupSwipeRefresh(view);
-        loadAppointmentData();
-        loadPets();
-        loadServices();
+        binding.fabAddAppointment.setOnClickListener(v -> openAppointmentDetails(-1));
 
-
-        FloatingActionButton fabAdd = view.findViewById(R.id.fabAddAppointment);
-        fabAdd.setOnClickListener(v -> openAppointmentDetails(-1));
-
-        hamburger.setOnClickListener(v -> {
-            ListFragment listFragment = (ListFragment) getParentFragment();
-            if (listFragment != null)
-                listFragment.openDrawer();
-        });
-
-        return view;
-    }
-
-    private void setupSearch(View view) {
-        etSearch = view.findViewById(R.id.etSearchAppointment);
-        etSearch.addTextChangedListener(new TextWatcher() {
-            @Override
-            public void beforeTextChanged(CharSequence s, int start, int count, int after) {
-            }
-
-            @Override
-            public void onTextChanged(CharSequence s, int start, int before, int count) {
-                filterAppointments(s.toString());
-            }
-
-            @Override
-            public void afterTextChanged(Editable s) {
-            }
-        });
-    }
-
-    private void filterAppointments(String query) {
-        filteredList.clear();
-        if (query.isEmpty()) {
-            filteredList.addAll(appointmentList);
-        } else {
-            String lower = query.toLowerCase();
-            for (AppointmentDTO a : appointmentList) {
-                if ((a.getCustomerName() != null && a.getCustomerName().toLowerCase().contains(lower))
-                        || (a.getServiceType() != null && a.getServiceType().toLowerCase().contains(lower))
-                        || (a.getPetName() != null && a.getPetName().toLowerCase().contains(lower))) {
-                    filteredList.add(a);
+        binding.btnHamburger.setOnClickListener(v -> {
+            Fragment parent = getParentFragment();
+            if (parent != null) {
+                Fragment grandParent = parent.getParentFragment();
+                if (grandParent instanceof ListFragment) {
+                    ((ListFragment) grandParent).openDrawer();
                 }
             }
+        });
+
+        binding.btnToggleCalendarMode.setOnClickListener(v -> toggleCalendarMode());
+
+        loadCurrentUserInfo();
+
+        return binding.getRoot();
+    }
+
+    private void setupBulkDelete() {
+        bulkDeleteHandler = new BulkDeleteHandler(
+                this,
+                binding.layoutBulkDelete,
+                binding.tvSelectionCount,
+                binding.btnBulkDelete,
+                adapter,
+                "appointment",
+                appointmentViewModel::bulkDeleteAppointments,
+                this::loadAppointmentData
+        );
+    }
+
+    @Override
+    public void onDestroyView() {
+        super.onDestroyView();
+        binding = null;
+    }
+
+    @Override
+    public void onResume() {
+        super.onResume();
+        loadAppointmentData();
+        loadStoreData();
+    }
+
+    /**
+     * Toggles the calendar between week and month display modes.
+     */
+    private void toggleCalendarMode() {
+        isMonthMode = !isMonthMode;
+        binding.calendarView.state().edit()
+                .setCalendarDisplayMode(isMonthMode ? CalendarMode.MONTHS : CalendarMode.WEEKS)
+                .commit();
+    }
+
+    /**
+     * Sets up the "My Appointments" filter button.
+     */
+    private void setupMyAppointmentFilter() {
+        binding.btnMyAppointments.setOnClickListener(v -> {
+            loadAppointmentData();
+        });
+    }
+
+    /**
+     * Fetches current user info to get the employeeId.
+     */
+    private void loadCurrentUserInfo() {
+        authViewModel.getMe().observe(getViewLifecycleOwner(), resource -> {
+            if (resource.status == Resource.Status.SUCCESS && resource.data != null) {
+                currentUserId = resource.data.getId();
+            }
+        });
+    }
+
+    /**
+     * Sets up the filter toggle button to show/hide the filter layout.
+     */
+    private void setupFilterToggle() {
+        binding.btnToggleFilter.setOnClickListener(v -> {
+            if (binding.layoutFilter.getVisibility() == View.GONE) {
+                binding.layoutFilter.setVisibility(View.VISIBLE);
+                binding.btnToggleFilter.setImageResource(android.R.drawable.ic_menu_close_clear_cancel);
+            } else {
+                binding.layoutFilter.setVisibility(View.GONE);
+                binding.btnToggleFilter.setImageResource(android.R.drawable.ic_menu_search);
+
+                // Reset filters when closing
+                binding.etSearchAppointment.setText("");
+                binding.spinnerStatus.setSelection(0);
+                binding.spinnerStore.setSelection(0);
+                binding.btnMyAppointments.setChecked(false);
+                selectedCalendarDay = null;
+                binding.calendarView.clearSelection();
+            }
+        });
+    }
+
+    /**
+     * Sets up the date selection listener for the calendar.
+     */
+    private void setupCalendar() {
+        binding.calendarView.setOnDateChangedListener((widget, date, selected) -> {
+            if (selected) {
+                if (date.equals(selectedCalendarDay)) {
+                    selectedCalendarDay = null;
+                    binding.calendarView.clearSelection();
+                } else {
+                    selectedCalendarDay = date;
+                }
+            } else {
+                selectedCalendarDay = null;
+            }
+            loadAppointmentData();
+        });
+    }
+
+    /**
+     * Updates calendar indicators to highlight dates that have scheduled appointments.
+     */
+    private void updateCalendarDecorators() {
+        HashSet<CalendarDay> datesWithAppointments = new HashSet<>();
+        for (AppointmentDTO appointment : appointmentList) {
+            try {
+                //Get the appointment date
+                Date date = dateFormat.parse(appointment.getAppointmentDate());
+                //if the date is not null, add it to the hashset
+                if (date != null) {
+                    Calendar cal = Calendar.getInstance();
+                    cal.setTime(date);
+                    datesWithAppointments.add(CalendarDay.from(cal.get(Calendar.YEAR), cal.get(Calendar.MONTH) + 1, cal.get(Calendar.DAY_OF_MONTH)));
+                }
+            } catch (ParseException e) {
+                Log.e("AppointmentFragment", "Error parsing date: " + appointment.getAppointmentDate());
+            }
         }
-        adapter.notifyDataSetChanged();
+        //update the indicators to the calendar
+        binding.calendarView.removeDecorators();
+        binding.calendarView.addDecorator(new EventDecorator(Color.RED, datesWithAppointments));
     }
 
-    private void setupSwipeRefresh(View view) {
-        swipeRefreshLayout = view.findViewById(R.id.swipeRefreshAppointment);
-        swipeRefreshLayout.setOnRefreshListener(this::loadAppointmentData);
+    /**
+     * Configures the search bar for filtering.
+     */
+    private void setupSearch() {
+        binding.etSearchAppointment.addTextChangedListener(new TextWatcher() {
+            @Override public void beforeTextChanged(CharSequence s, int start, int count, int after) {}
+            @Override public void onTextChanged(CharSequence s, int start, int before, int count) {
+                loadAppointmentData();
+            }
+            @Override public void afterTextChanged(Editable s) {}
+        });
     }
 
+    /**
+     * Configures the status filter spinner.
+     */
+    private void setupStatusFilter() {
+        String[] statuses = {"All Statuses", "Booked", "Completed", "Cancelled", "Missed"};
+        SpinnerUtils.setupStringFilterSpinner(requireContext(), binding.spinnerStatus, statuses, this::loadAppointmentData);
+    }
+
+    /**
+     * Configures the store filter spinner.
+     */
+    private void setupStoreFilter() {
+        SpinnerUtils.setupFilterSpinner(binding.spinnerStore, this::loadAppointmentData);
+    }
+
+    /**
+     * Fetches store data to populate the store filter.
+     */
+    private void loadStoreData() {
+        storeViewModel.getAllStores(0, 100).observe(getViewLifecycleOwner(), resource -> {
+            if (resource.status == Resource.Status.SUCCESS && resource.data != null) {
+                storeList = resource.data.getContent();
+                SpinnerUtils.populateWhiteSpinner(requireContext(), binding.spinnerStore, storeList,
+                        StoreDTO::getStoreName, "All Stores", -1L, StoreDTO::getStoreId);
+            }
+        });
+    }
+
+    /**
+     * Initializes the SwipeRefreshLayout to allow manual data refreshing.
+     */
+    private void setupSwipeRefresh() {
+        binding.swipeRefreshAppointment.setOnRefreshListener(this::loadAppointmentData);
+    }
+
+    /**
+     * Navigates to the appointment detail screen for editing or creating an appointment.
+     */
     private void openAppointmentDetails(int position) {
-        AppointmentDetailFragment detailFragment = new AppointmentDetailFragment();
         Bundle args = new Bundle();
-
         if (position != -1) {
-            AppointmentDTO a = filteredList.get(position);
+            AppointmentDTO a = appointmentList.get(position);
             args.putLong("appointmentId", a.getAppointmentId());
-            args.putString("appointmentDate", a.getAppointmentDate());
-            args.putString("appointmentTime", a.getAppointmentTime());
-            args.putString("appointmentStatus", a.getAppointmentStatus());
-            // IDs for pre-selecting spinners
-            if (a.getPetID() != null)      args.putLong("petId", a.getPetID());
-            if (a.getServiceId() != null)  args.putLong("serviceId", a.getServiceId());
-            if (a.getCustomerId() != null) args.putLong("customerId", a.getCustomerId());
-            if (a.getStoreId() != null)    args.putLong("storeId", a.getStoreId());
         }
-
-        detailFragment.setArguments(args);
-        ListFragment lf = (ListFragment) getParentFragment();
-        if (lf != null) lf.loadFragment(detailFragment);
-    }
-    public void onAppointmentSaved(int position, AppointmentDTO appointment) {
-        if (position == -1) {
-            appointmentList.add(appointment);
-        } else {
-            appointmentList.set(position, appointment);
-        }
-        filterAppointments(etSearch.getText().toString());
-    }
-
-    public void onAppointmentDeleted(int position) {
-        appointmentList.remove(position);
-        filterAppointments(etSearch.getText().toString());
+        NavHostFragment.findNavController(this).navigate(R.id.nav_appointment_detail, args);
     }
 
+    /**
+     * Handles item click in the appointment list.
+     */
     @Override
     public void onAppointmentClick(int position) {
         openAppointmentDetails(position);
     }
 
+    @Override
+    public void onSelectionChanged(int count) {
+        if (bulkDeleteHandler != null) {
+            bulkDeleteHandler.onSelectionChanged(count);
+        }
+    }
+
+    /**
+     * Fetches appointment data from the server with all active filters.
+     */
     private void loadAppointmentData() {
-        if (swipeRefreshLayout != null)
-            swipeRefreshLayout.setRefreshing(true);
-        api.getAllAppointments(0, 100).enqueue(new Callback<PageResponse<AppointmentDTO>>() {
-            @Override
-            public void onResponse(Call<PageResponse<AppointmentDTO>> call,
-                                   Response<PageResponse<AppointmentDTO>> response) {
-                if (swipeRefreshLayout != null)
-                    swipeRefreshLayout.setRefreshing(false);
-                if (response.isSuccessful() && response.body() != null) {
-                    appointmentList.clear();
-                    appointmentList.addAll(response.body().getContent());
-                    filterAppointments(etSearch != null ? etSearch.getText().toString() : "");
-                } else {
-                    Log.e("AppointmentFragment", "Error: " + response.message());
-                    Toast.makeText(getContext(), "Failed to load appointments", Toast.LENGTH_SHORT).show();
-                }
-            }
-
-            @Override
-            public void onFailure(Call<PageResponse<AppointmentDTO>> call, Throwable t) {
-                if (swipeRefreshLayout != null)
-                    swipeRefreshLayout.setRefreshing(false);
-                Toast.makeText(getContext(), "Network error: " + t.getMessage(), Toast.LENGTH_SHORT).show();
-                Log.e("AppointmentFragment", t.getMessage());
-            }
-        });
-    }
-
-
-
-    // Load Pets
-    private void loadPets() {
-        PetApi petApi = RetrofitClient.getPetApi(requireContext());
-        petApi.getAllPets(0,100).enqueue(new Callback<PageResponse<PetDTO>>() {
-
-            @Override
-            public void onResponse(Call<PageResponse<PetDTO>> call, Response<PageResponse<PetDTO>> response) {
-                if (response.isSuccessful() && response.body() !=null) {
-                    petList.clear();
-                    petList.addAll(response.body().getContent());
-                }
-            }
-
-            @Override
-            public void onFailure(Call<PageResponse<PetDTO>> call, Throwable t) {
-
-                Log.e("AppointmentFragment", "Pet load error:" + t.getMessage());
-
-            }
-        });
-    }
-
-    // Load Services
-
-    private void loadServices() {
-        ServiceApi serviceApi = RetrofitClient.getServiceApi(requireContext());
-
-        serviceApi.getAllServices(0,100).enqueue(new Callback<PageResponse<ServiceDTO>>() {
-            @Override
-            public void onResponse(Call<PageResponse<ServiceDTO>> call, Response<PageResponse<ServiceDTO>> response) {
-                if (response.isSuccessful() && response.body() != null) {
-                    serviceList.clear();
-                    serviceList.addAll(response.body().getContent());
-
-                }
-            }
-
-            @Override
-            public void onFailure(Call<PageResponse<ServiceDTO>> call, Throwable t) {
-                Log.e("AppointmentFragmnet", "Service load error: " + t.getMessage());
-
-            }
-        });
-    }
-
-    private String getPetName(Long id) {
-        for (PetDTO p : petList) {
-            if (p.getPetId().equals(id)) return p.getPetName();
-
+        String query = binding.etSearchAppointment.getText().toString().trim();
+        String status = binding.spinnerStatus.getSelectedItem() != null ? binding.spinnerStatus.getSelectedItem().toString() : "All Statuses";
+        
+        Long storeId = null;
+        if (binding.spinnerStore.getSelectedItemPosition() > 0 && !storeList.isEmpty()) {
+            storeId = storeList.get(binding.spinnerStore.getSelectedItemPosition() - 1).getStoreId();
         }
-        return  "";
-    }
 
-    private String getServiceName(Long id) {
-        for (ServiceDTO s : serviceList) {
-            if (s.getServiceId().equals(id))return s.getServiceName();
+        String selectedDateString = null;
+        if (selectedCalendarDay != null) {
+            selectedDateString = String.format(Locale.getDefault(), "%04d-%02d-%02d",
+                    selectedCalendarDay.getYear(), selectedCalendarDay.getMonth(), selectedCalendarDay.getDay());
         }
-        return "";
+
+        Long employeeId = null;
+        if (binding.btnMyAppointments.isChecked()) {
+            employeeId = currentUserId;
+        }
+
+        if (status.equals("All Statuses")) status = null;
+        else status = status.toUpperCase();
+
+        appointmentViewModel.getAllAppointments(0, 500, query, status, storeId, selectedDateString, employeeId).observe(getViewLifecycleOwner(), resource -> {
+            if (resource == null) return;
+
+            // Check the status to see if the resource is loaded and display the data
+            switch (resource.status) {
+                case LOADING:
+                    // Show loading indicator
+                    binding.swipeRefreshAppointment.setRefreshing(true);
+                    break;
+                case SUCCESS:
+                    // Hide loading indicator and display data
+                    binding.swipeRefreshAppointment.setRefreshing(false);
+                    if (resource.data != null) {
+                        appointmentList.clear();
+                        appointmentList.addAll(resource.data.getContent());
+                        updateCalendarDecorators();
+                        adapter.notifyDataSetChanged();
+                    }
+                    break;
+                case ERROR:
+                    // Hide loading indicator and toast error message
+                    binding.swipeRefreshAppointment.setRefreshing(false);
+                    Toast.makeText(getContext(), "Failed to load appointments: " + resource.message, Toast.LENGTH_SHORT).show();
+                    Log.e("AppointmentFragment", "Error loading appointments: " + resource.message);
+                    break;
+            }
+        });
     }
 
-    private void setupRecyclerView(View view) {
-        RecyclerView recyclerView = view.findViewById(R.id.recyclerViewAppointments);
-        adapter = new AppointmentAdapter(filteredList, this);
-        recyclerView.setLayoutManager(new LinearLayoutManager(getContext()));
-        recyclerView.setAdapter(adapter);
+    /**
+     * Initializes the RecyclerView for displaying appointments.
+     */
+    private void setupRecyclerView() {
+        adapter = new AppointmentAdapter(appointmentList, this);
+        binding.recyclerViewAppointments.setLayoutManager(new LinearLayoutManager(getContext()));
+        binding.recyclerViewAppointments.setAdapter(adapter);
     }
 }

android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/InventoryFragment.java

@@ -1,213 +1,182 @@
 package com.example.petstoremobile.fragments.listfragments;
 
 import android.os.Bundle;
-import android.os.Handler;
-import android.os.Looper;
 import android.text.Editable;
 import android.text.TextWatcher;
 import android.util.Log;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
-import android.widget.AdapterView;
-import android.widget.ArrayAdapter;
-import android.widget.Button;
-import android.widget.EditText;
-import android.widget.ImageButton;
-import android.widget.Spinner;
-import android.widget.TextView;
 import android.widget.Toast;
 
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 import androidx.fragment.app.Fragment;
+import androidx.lifecycle.ViewModelProvider;
+import androidx.navigation.fragment.NavHostFragment;
 import androidx.recyclerview.widget.LinearLayoutManager;
 import androidx.recyclerview.widget.RecyclerView;
-import androidx.swiperefreshlayout.widget.SwipeRefreshLayout;
 
 import com.example.petstoremobile.R;
 import com.example.petstoremobile.adapters.InventoryAdapter;
-import com.example.petstoremobile.api.CategoryApi;
-import com.example.petstoremobile.api.InventoryApi;
-import com.example.petstoremobile.api.RetrofitClient;
-import com.example.petstoremobile.dtos.BulkDeleteRequest;
-import com.example.petstoremobile.dtos.CategoryDTO;
+import com.example.petstoremobile.databinding.FragmentInventoryBinding;
 import com.example.petstoremobile.dtos.InventoryDTO;
-import com.example.petstoremobile.dtos.PageResponse;
+import com.example.petstoremobile.dtos.StoreDTO;
 import com.example.petstoremobile.fragments.ListFragment;
-import com.example.petstoremobile.fragments.listfragments.detailfragments.InventoryDetailFragment;
-import com.google.android.material.floatingactionbutton.FloatingActionButton;
+import com.example.petstoremobile.utils.BulkDeleteHandler;
+import com.example.petstoremobile.viewmodels.InventoryViewModel;
+import com.example.petstoremobile.utils.Resource;
+import com.example.petstoremobile.utils.SpinnerUtils;
 
 import java.util.ArrayList;
 import java.util.List;
 
-import retrofit2.Call;
-import retrofit2.Callback;
-import retrofit2.Response;
+import dagger.hilt.android.AndroidEntryPoint;
 
+@AndroidEntryPoint
 public class InventoryFragment extends Fragment implements InventoryAdapter.OnInventoryClickListener {
 
     private static final String TAG = "InventoryFragment";
     private static final int PAGE_SIZE = 20;
 
+    private FragmentInventoryBinding binding;
     private final List<InventoryDTO> inventoryList = new ArrayList<>();
-    private final List<CategoryDTO> categoryList = new ArrayList<>();
+    private List<StoreDTO> storeList = new ArrayList<>();
     private InventoryAdapter adapter;
-    private InventoryApi inventoryApi;
-    private CategoryApi categoryApi;
-
-    private SwipeRefreshLayout swipeRefreshLayout;
-    private EditText etSearch;
-    private Spinner spinnerCategory;
-    private ImageButton hamburger;
-    private Button btnBulkDelete;
-    private TextView tvSelectionCount;
-
-    // Debounce search
-    private final Handler searchHandler = new Handler(Looper.getMainLooper());
-    private Runnable searchRunnable;
-    private String currentQuery = "";
-
-    // Selected category filter — null means "All"
-    private String selectedCategory = null;
+    private InventoryViewModel viewModel;
+    private BulkDeleteHandler bulkDeleteHandler;
 
     // Pagination
     private int currentPage = 0;
     private boolean isLastPage = false;
     private boolean isLoading = false;
 
-    // Prevent spinner from firing on initial load
-    private boolean spinnerReady = false;
+    /**
+     * Initializes the fragment and its ViewModel.
+     */
+    @Override
+    public void onCreate(@Nullable Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        viewModel = new ViewModelProvider(this).get(InventoryViewModel.class);
+    }
+
+    /**
+     * Sets up the fragment's UI components, including the inventory list and search.
+     */
+    @Override
+    public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
+                             Bundle savedInstanceState) {
+        binding = FragmentInventoryBinding.inflate(inflater, container, false);
+
+        setupRecyclerView();
+        setupSearch();
+        setupStoreFilter();
+        setupSwipeRefresh();
+        setupFilterToggle();
+        setupBulkDelete();
+        loadInventory(true);
+        loadStoreData();
+
+        binding.fabAddInventory.setOnClickListener(v -> openDetail(null));
+
+        binding.btnHamburger.setOnClickListener(v -> {
+            Fragment parent = getParentFragment();
+            if (parent != null) {
+                Fragment grandParent = parent.getParentFragment();
+                if (grandParent instanceof ListFragment) {
+                    ((ListFragment) grandParent).openDrawer();
+                }
+            }
+        });
+
+        return binding.getRoot();
+    }
+
+    private void setupBulkDelete() {
+        bulkDeleteHandler = new BulkDeleteHandler(
+                this,
+                binding.layoutBulkDelete,
+                binding.tvSelectionCount,
+                binding.btnBulkDelete,
+                adapter,
+                "inventory item",
+                viewModel::bulkDeleteInventory,
+                () -> loadInventory(true)
+        );
+    }
 
     @Override
-    public View onCreateView(LayoutInflater inflater, ViewGroup container,
-                             Bundle savedInstanceState) {
-        View view = inflater.inflate(R.layout.fragment_inventory, container, false);
-
-        inventoryApi = RetrofitClient.getInventoryApi(requireContext());
-        categoryApi = RetrofitClient.getCategoryApi(requireContext());
-
-        hamburger = view.findViewById(R.id.btnHamburger);
-        btnBulkDelete = view.findViewById(R.id.btnBulkDelete);
-        tvSelectionCount = view.findViewById(R.id.tvSelectionCount);
-        spinnerCategory = view.findViewById(R.id.spinnerCategory);
-
-        setupRecyclerView(view);
-        setupSearch(view);
-        setupSwipeRefresh(view);
-        loadCategories(); // loads categories then triggers loadInventory
-        loadInventory(true);
-
-        view.findViewById(R.id.fabAddInventory)
-                .setOnClickListener(v -> openDetail(null));
-
-        hamburger.setOnClickListener(v -> {
-            ListFragment lf = (ListFragment) getParentFragment();
-            if (lf != null)
-                lf.openDrawer();
-        });
-
-        btnBulkDelete.setOnClickListener(v -> confirmBulkDelete());
-
-        return view;
+    public void onDestroyView() {
+        super.onDestroyView();
+        binding = null;
     }
 
-    // Categories
-    private void loadCategories() {
-        categoryApi.getAllCategories(0, 100).enqueue(new Callback<PageResponse<CategoryDTO>>() {
-            @Override
-            public void onResponse(Call<PageResponse<CategoryDTO>> call,
-                                   Response<PageResponse<CategoryDTO>> response) {
-                if (response.isSuccessful() && response.body() != null) {
-                    categoryList.clear();
-                    categoryList.addAll(response.body().getContent());
-                    setupCategorySpinner();
-                }
-            }
+    /**
+     * Sets up the filter toggle button to show/hide the filter layout.
+     */
+    private void setupFilterToggle() {
+        binding.btnToggleFilter.setOnClickListener(v -> {
+            if (binding.layoutFilter.getVisibility() == View.GONE) {
+                binding.layoutFilter.setVisibility(View.VISIBLE);
+                binding.btnToggleFilter.setImageResource(android.R.drawable.ic_menu_close_clear_cancel);
+            } else {
+                binding.layoutFilter.setVisibility(View.GONE);
+                binding.btnToggleFilter.setImageResource(android.R.drawable.ic_menu_search);
 
-            @Override
-            public void onFailure(Call<PageResponse<CategoryDTO>> call, Throwable t) {
-                Log.e(TAG, "Failed to load categories", t);
-                // Still setup spinner with just "All"
-                setupCategorySpinner();
+                // Reset filters when closing
+                binding.etSearchInventory.setText("");
+                binding.spinnerStore.setSelection(0);
             }
         });
     }
 
-    private void setupCategorySpinner() {
-        // First item is always "All Categories"
-        List<String> categoryNames = new ArrayList<>();
-        categoryNames.add("All Categories");
-        for (CategoryDTO c : categoryList) {
-            categoryNames.add(c.getCategoryName());
-        }
-
-        ArrayAdapter<String> spinnerAdapter = new ArrayAdapter<>(
-                requireContext(),
-                android.R.layout.simple_spinner_item,
-                categoryNames);
-        spinnerAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
-        spinnerCategory.setAdapter(spinnerAdapter);
-
-        spinnerCategory.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
-            @Override
-            public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
-                if (!spinnerReady) {
-                    // Skip the first automatic trigger on setup
-                    spinnerReady = true;
-                    return;
-                }
-                if (position == 0) {
-                    selectedCategory = null; // "All Categories"
-                } else {
-                    selectedCategory = categoryList.get(position - 1).getCategoryName();
-                }
+    /**
+     * Sets up the search bar for filtering.
+     */
+    private void setupSearch() {
+        binding.etSearchInventory.addTextChangedListener(new TextWatcher() {
+            @Override public void beforeTextChanged(CharSequence s, int start, int count, int after) {}
+            @Override public void onTextChanged(CharSequence s, int start, int before, int count) {
                 loadInventory(true);
             }
+            @Override public void afterTextChanged(Editable s) {}
+        });
+    }
 
-            @Override
-            public void onNothingSelected(AdapterView<?> parent) {
+    /**
+     * Configures the store filter spinner.
+     */
+    private void setupStoreFilter() {
+        SpinnerUtils.setupFilterSpinner(binding.spinnerStore, () -> loadInventory(true));
+    }
+
+    /**
+     * Fetches store data to populate the store filter.
+     */
+    private void loadStoreData() {
+        viewModel.getAllStores(0, 100).observe(getViewLifecycleOwner(), resource -> {
+            if (resource.status == Resource.Status.SUCCESS && resource.data != null) {
+                storeList = resource.data.getContent();
+                SpinnerUtils.populateWhiteSpinner(requireContext(), binding.spinnerStore, storeList,
+                        StoreDTO::getStoreName, "All Stores", -1L, StoreDTO::getStoreId);
             }
         });
     }
 
-    // Search
-
-    private void setupSearch(View view) {
-        etSearch = view.findViewById(R.id.etSearchInventory);
-        etSearch.addTextChangedListener(new TextWatcher() {
-            @Override
-            public void beforeTextChanged(CharSequence s, int i, int i1, int i2) {
-            }
-
-            @Override
-            public void afterTextChanged(Editable s) {
-            }
-
-            @Override
-            public void onTextChanged(CharSequence s, int start, int before, int count) {
-                if (searchRunnable != null)
-                    searchHandler.removeCallbacks(searchRunnable);
-                searchRunnable = () -> {
-                    currentQuery = s.toString().trim();
-                    loadInventory(true);
-                };
-                searchHandler.postDelayed(searchRunnable, 400);
-            }
-        });
-    }
-
-    // RecyclerView + infinite scroll
-    private void setupRecyclerView(View view) {
-        RecyclerView rv = view.findViewById(R.id.recyclerViewInventory);
+    /**
+     * Initializes the RecyclerView with a layout manager, and adapter.
+     */
+    private void setupRecyclerView() {
         adapter = new InventoryAdapter(inventoryList, this);
-        rv.setLayoutManager(new LinearLayoutManager(getContext()));
-        rv.setAdapter(adapter);
+        binding.recyclerViewInventory.setLayoutManager(new LinearLayoutManager(getContext()));
+        binding.recyclerViewInventory.setAdapter(adapter);
 
-        rv.addOnScrollListener(new RecyclerView.OnScrollListener() {
+        binding.recyclerViewInventory.addOnScrollListener(new RecyclerView.OnScrollListener() {
             @Override
-            public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
+            public void onScrolled(@NonNull RecyclerView recyclerView, int dx, int dy) {
                 if (dy <= 0)
                     return;
-                LinearLayoutManager lm = (LinearLayoutManager) rv.getLayoutManager();
+                LinearLayoutManager lm = (LinearLayoutManager) binding.recyclerViewInventory.getLayoutManager();
                 if (lm == null)
                     return;
                 int visible = lm.getChildCount();
@@ -220,144 +189,90 @@ public class InventoryFragment extends Fragment implements InventoryAdapter.OnIn
         });
     }
 
-    private void setupSwipeRefresh(View view) {
-        swipeRefreshLayout = view.findViewById(R.id.swipeRefreshInventory);
-        swipeRefreshLayout.setOnRefreshListener(() -> loadInventory(true));
+    /**
+     * Sets up the SwipeRefreshLayout to reload the first page of inventory items.
+     */
+    private void setupSwipeRefresh() {
+        binding.swipeRefreshInventory.setOnRefreshListener(() -> loadInventory(true));
     }
 
-    // Load inventory
+    /**
+     * Fetches a page of inventory items from the API.
+     */
     private void loadInventory(boolean reset) {
-        if (isLoading)
-            return;
-        isLoading = true;
+        if (isLoading) return;
 
         if (reset) {
             currentPage = 0;
             isLastPage = false;
         }
 
-        // Build query: combine search text + selected category
-        String q = buildQuery();
+        // Search text from input
+        String query = binding.etSearchInventory != null ? binding.etSearchInventory.getText().toString().trim() : "";
+        if (query.isEmpty()) query = null;
 
-        inventoryApi.getAllInventory(q, currentPage, PAGE_SIZE, "inventoryId,asc")
-                .enqueue(new Callback<PageResponse<InventoryDTO>>() {
-                    @Override
-                    public void onResponse(Call<PageResponse<InventoryDTO>> call,
-                                           Response<PageResponse<InventoryDTO>> response) {
-                        isLoading = false;
-                        if (swipeRefreshLayout != null)
-                            swipeRefreshLayout.setRefreshing(false);
-
-                        if (response.isSuccessful() && response.body() != null) {
-                            PageResponse<InventoryDTO> page = response.body();
-                            if (reset)
-                                inventoryList.clear();
-                            inventoryList.addAll(page.getContent());
-                            adapter.notifyDataSetChanged();
-                            isLastPage = page.isLast();
-                            if (!isLastPage)
-                                currentPage++;
-                        } else {
-                            Log.e(TAG, "Error " + response.code());
-                            Toast.makeText(getContext(), "Failed to load inventory", Toast.LENGTH_SHORT).show();
-                        }
-                    }
-
-                    @Override
-                    public void onFailure(Call<PageResponse<InventoryDTO>> call, Throwable t) {
-                        isLoading = false;
-                        if (swipeRefreshLayout != null)
-                            swipeRefreshLayout.setRefreshing(false);
-                        Log.e(TAG, "Network error", t);
-                        Toast.makeText(getContext(), "Network error: " + t.getMessage(), Toast.LENGTH_SHORT).show();
-                    }
-                });
-    }
-
-    // Combines search text and category into one query string for ?q=
-    private String buildQuery() {
-        String q = null;
-        if (!currentQuery.isEmpty() && selectedCategory != null) {
-            // Both active — prioritize search text, category acts as context
-            q = currentQuery;
-        } else if (!currentQuery.isEmpty()) {
-            q = currentQuery;
-        } else if (selectedCategory != null) {
-            q = selectedCategory;
+        Long storeId = null;
+        if (binding.spinnerStore.getSelectedItemPosition() > 0 && !storeList.isEmpty()) {
+            storeId = storeList.get(binding.spinnerStore.getSelectedItemPosition() - 1).getStoreId();
         }
-        return q;
-    }
 
-    // Bulk delete
-    private void confirmBulkDelete() {
-        List<Long> ids = adapter.getSelectedIds();
-        if (ids.isEmpty())
-            return;
+        //Load all inventory items from the backend using viewModel
+        viewModel.getAllInventory(query, storeId, currentPage, PAGE_SIZE, "product.prodName").observe(getViewLifecycleOwner(), resource -> {
+            if (resource == null) return;
 
-        new androidx.appcompat.app.AlertDialog.Builder(requireContext())
-                .setTitle("Delete " + ids.size() + " item(s)?")
-                .setMessage("This cannot be undone.")
-                .setPositiveButton("Delete", (d, w) -> bulkDelete(ids))
-                .setNegativeButton("Cancel", null)
-                .show();
-    }
-
-    private void bulkDelete(List<Long> ids) {
-        inventoryApi.bulkDeleteInventory(new BulkDeleteRequest(ids))
-                .enqueue(new Callback<Void>() {
-                    @Override
-                    public void onResponse(Call<Void> call, Response<Void> response) {
-                        if (response.isSuccessful()) {
-                            adapter.clearSelection();
-                            hideBulkDeleteBar();
-                            loadInventory(true);
-                            Toast.makeText(getContext(), ids.size() + " item(s) deleted", Toast.LENGTH_SHORT).show();
-                        } else {
-                            Toast.makeText(getContext(), "Delete failed", Toast.LENGTH_SHORT).show();
-                        }
+            // Check the status to see if the resource is loaded and display the data
+            switch (resource.status) {
+                case LOADING:
+                    // Show loading indicator
+                    isLoading = true;
+                    binding.swipeRefreshInventory.setRefreshing(true);
+                    break;
+                case SUCCESS:
+                    // Hide loading indicator and display data
+                    isLoading = false;
+                    binding.swipeRefreshInventory.setRefreshing(false);
+                    if (resource.data != null) {
+                        if (reset) inventoryList.clear();
+                        inventoryList.addAll(resource.data.getContent());
+                        adapter.notifyDataSetChanged();
+                        isLastPage = resource.data.isLast();
+                        if (!isLastPage) currentPage++;
                     }
-
-                    @Override
-                    public void onFailure(Call<Void> call, Throwable t) {
-                        Toast.makeText(getContext(), "Network error", Toast.LENGTH_SHORT).show();
-                    }
-                });
+                    break;
+                case ERROR:
+                    // Hide loading indicator and toast error message
+                    isLoading = false;
+                    binding.swipeRefreshInventory.setRefreshing(false);
+                    Log.e(TAG, "Error: " + resource.message);
+                    Toast.makeText(getContext(), "Failed to load inventory: " + resource.message, Toast.LENGTH_SHORT).show();
+                    break;
+            }
+        });
     }
 
-    private void hideBulkDeleteBar() {
-        if (btnBulkDelete != null)
-            btnBulkDelete.setVisibility(View.GONE);
-        if (tvSelectionCount != null)
-            tvSelectionCount.setVisibility(View.GONE);
-    }
-
-    // Navigation
+    /**
+     * Navigates to the inventory detail screen for a specific item or to add a new one.
+     */
     private void openDetail(InventoryDTO inv) {
-        InventoryDetailFragment detail = new InventoryDetailFragment();
         Bundle args = new Bundle();
 
         if (inv != null) {
             args.putLong("inventoryId", inv.getInventoryId());
-            args.putLong("prodId", inv.getProdId() != null ? inv.getProdId() : -1);
-            args.putString("productName", inv.getProductName());
-            args.putString("categoryName", inv.getCategoryName());
-            args.putInt("quantity", inv.getQuantity() != null ? inv.getQuantity() : 0);
         }
 
-        detail.setArguments(args);
-        detail.setInventoryFragment(this);
-
-        ListFragment lf = (ListFragment) getParentFragment();
-        if (lf != null)
-            lf.loadFragment(detail);
+        NavHostFragment.findNavController(this).navigate(R.id.nav_inventory_detail, args);
     }
 
+    /**
+     * Reloads inventory data when changes occur.
+     */
     public void onInventoryChanged() {
         loadInventory(true);
     }
 
-    // Adapter callbacks
-
+    /**
+     * Handles item click in the inventory list.
+     */
     @Override
     public void onInventoryClick(int position) {
         if (position >= 0 && position < inventoryList.size()) {
@@ -365,14 +280,13 @@ public class InventoryFragment extends Fragment implements InventoryAdapter.OnIn
         }
     }
 
+    /**
+     * Updates the bulk deletion UI visibility and count when items are selected or deselected.
+     */
     @Override
     public void onSelectionChanged(int selectedCount) {
-        if (selectedCount > 0) {
-            btnBulkDelete.setVisibility(View.VISIBLE);
-            tvSelectionCount.setVisibility(View.VISIBLE);
-            tvSelectionCount.setText(selectedCount + " selected");
-        } else {
-            hideBulkDeleteBar();
+        if (bulkDeleteHandler != null) {
+            bulkDeleteHandler.onSelectionChanged(selectedCount);
         }
     }
-}
+}

android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/PetFragment.java

@@ -2,10 +2,12 @@ package com.example.petstoremobile.fragments.listfragments;
 
 import android.os.Bundle;
 
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 import androidx.fragment.app.Fragment;
+import androidx.lifecycle.ViewModelProvider;
+import androidx.navigation.fragment.NavHostFragment;
 import androidx.recyclerview.widget.LinearLayoutManager;
-import androidx.recyclerview.widget.RecyclerView;
-import androidx.swiperefreshlayout.widget.SwipeRefreshLayout;
 
 import android.text.Editable;
 import android.text.TextWatcher;
@@ -13,219 +15,264 @@ import android.util.Log;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
-import android.widget.AdapterView;
-import android.widget.ArrayAdapter;
-import android.widget.EditText;
-import android.widget.ImageButton;
-import android.widget.Spinner;
 import android.widget.Toast;
 
 import com.example.petstoremobile.R;
 import com.example.petstoremobile.adapters.PetAdapter;
-import com.example.petstoremobile.api.PetApi;
-import com.example.petstoremobile.api.RetrofitClient;
-import com.example.petstoremobile.dtos.PageResponse;
+import com.example.petstoremobile.databinding.FragmentPetBinding;
 import com.example.petstoremobile.dtos.PetDTO;
+import com.example.petstoremobile.dtos.StoreDTO;
 import com.example.petstoremobile.fragments.ListFragment;
-import com.example.petstoremobile.fragments.listfragments.detailfragments.PetDetailFragment;
-import com.example.petstoremobile.fragments.listfragments.listprofilefragments.PetProfileFragment;
-import com.google.android.material.floatingactionbutton.FloatingActionButton;
+import com.example.petstoremobile.utils.BulkDeleteHandler;
+import com.example.petstoremobile.utils.Resource;
+import com.example.petstoremobile.utils.SpinnerUtils;
+import com.example.petstoremobile.viewmodels.PetViewModel;
+import com.example.petstoremobile.viewmodels.StoreViewModel;
 
 import java.util.ArrayList;
 import java.util.List;
 
-import retrofit2.Call;
-import retrofit2.Callback;
-import retrofit2.Response;
+import javax.inject.Inject;
+import javax.inject.Named;
 
+import dagger.hilt.android.AndroidEntryPoint;
+
+@AndroidEntryPoint
 public class PetFragment extends Fragment implements PetAdapter.OnPetClickListener {
+    private FragmentPetBinding binding;
     private List<PetDTO> petList = new ArrayList<>();
-    private List<PetDTO> filteredList = new ArrayList<>();
-    private ImageButton hamburger;
+    private List<StoreDTO> storeList = new ArrayList<>();
     private PetAdapter adapter;
-    private PetApi api;
-    private SwipeRefreshLayout swipeRefreshLayout;
-    private EditText etSearch;
-    private Spinner spinnerStatus;
+    private PetViewModel viewModel;
+    private StoreViewModel storeViewModel;
+    private BulkDeleteHandler bulkDeleteHandler;
 
-    //load pet view
+    @Inject @Named("baseUrl") String baseUrl;
+
+    /**
+     * Initializes the fragment and its associated ViewModels.
+     */
     @Override
-    public View onCreateView(LayoutInflater inflater, ViewGroup container,
+    public void onCreate(@Nullable Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        viewModel = new ViewModelProvider(this).get(PetViewModel.class);
+        storeViewModel = new ViewModelProvider(this).get(StoreViewModel.class);
+    }
+
+    /**
+     * Sets up the fragment's UI components, including RecyclerView, filters, and swipe-to-refresh.
+     */
+    @Override
+    public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
-        View view = inflater.inflate(R.layout.fragment_pet, container, false);
+        binding = FragmentPetBinding.inflate(inflater, container, false);
 
-        //get retrofit
-        api = RetrofitClient.getPetApi(requireContext());
+        setupRecyclerView();
+        setupSearch();
+        setupStatusFilter();
+        setupSpeciesFilter();
+        setupStoreFilter();
+        setupSwipeRefresh();
+        setupFilterToggle();
+        setupBulkDelete();
 
-        hamburger = view.findViewById(R.id.btnHamburger);
+        binding.fabAddPet.setOnClickListener(v -> openPetDetails());
 
-        setupRecyclerView(view);
-        setupSearch(view);
-        setupStatusFilter(view);
-        setupSwipeRefresh(view);
-        loadPetData();
-
-
-        //Add button to opens the add dialog
-        FloatingActionButton fabAddPet = view.findViewById(R.id.fabAddPet);
-        fabAddPet.setOnClickListener(v -> openPetDetails(-1));
-
-        //Make the hamburger button open the drawer from listFragment
-        hamburger.setOnClickListener(v -> {
-            ListFragment listFragment = (ListFragment) getParentFragment();
-            //if list fragment is found then use its helper function to open the drawer
-            if (listFragment != null) {
-                listFragment.openDrawer();
+        binding.btnHamburger.setOnClickListener(v -> {
+            Fragment parent = getParentFragment();
+            if (parent != null) {
+                Fragment grandParent = parent.getParentFragment();
+                if (grandParent instanceof ListFragment) {
+                    ((ListFragment) grandParent).openDrawer();
+                }
             }
         });
 
-        return view;
+        return binding.getRoot();
     }
 
-    private void setupSearch(View view) {
-        etSearch = view.findViewById(R.id.etSearchPet);
-        etSearch.addTextChangedListener(new TextWatcher() {
+    private void setupBulkDelete() {
+        bulkDeleteHandler = new BulkDeleteHandler(
+                this,
+                binding.layoutBulkDelete,
+                binding.tvSelectionCount,
+                binding.btnBulkDelete,
+                adapter,
+                "pet",
+                viewModel::bulkDeletePets,
+                this::loadPetData
+        );
+    }
+
+    @Override
+    public void onDestroyView() {
+        super.onDestroyView();
+        binding = null;
+    }
+
+    /**
+     * Reloads data every time the fragment becomes visible.
+     */
+    @Override
+    public void onResume() {
+        super.onResume();
+        loadPetData();
+        loadStoreData();
+    }
+
+    /**
+     * Sets up the filter toggle button to show/hide the filter layout.
+     */
+    private void setupFilterToggle() {
+        binding.btnToggleFilter.setOnClickListener(v -> {
+            if (binding.layoutFilter.getVisibility() == View.GONE) {
+                binding.layoutFilter.setVisibility(View.VISIBLE);
+                binding.btnToggleFilter.setImageResource(android.R.drawable.ic_menu_close_clear_cancel);
+            } else {
+                binding.layoutFilter.setVisibility(View.GONE);
+                binding.btnToggleFilter.setImageResource(android.R.drawable.ic_menu_search);
+
+                // Reset filters when closing
+                binding.etSearchPet.setText("");
+                binding.spinnerStatus.setSelection(0);
+                binding.spinnerSpecies.setSelection(0);
+                binding.spinnerStore.setSelection(0);
+            }
+        });
+    }
+
+    /**
+     * Configures the search bar.
+     */
+    private void setupSearch() {
+        binding.etSearchPet.addTextChangedListener(new TextWatcher() {
             @Override public void beforeTextChanged(CharSequence s, int start, int count, int after) {}
             @Override public void onTextChanged(CharSequence s, int start, int before, int count) {
-                filterPets();
+                loadPetData();
             }
             @Override public void afterTextChanged(Editable s) {}
         });
     }
 
-    //Setup the status filter spinner
-    private void setupStatusFilter(View view) {
-        spinnerStatus = view.findViewById(R.id.spinnerStatus);
-        String[] statuses = {"All Statuses", "Available", "Adopted"};
-        ArrayAdapter<String> adapter = new ArrayAdapter<>(requireContext(), android.R.layout.simple_spinner_item, statuses);
-        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
-        spinnerStatus.setAdapter(adapter);
+    /**
+     * Configures the status filter spinner.
+     */
+    private void setupStatusFilter() {
+        String[] statuses = {"All Statuses", "Available", "Adopted", "Owned"};
+        SpinnerUtils.setupStringFilterSpinner(requireContext(), binding.spinnerStatus, statuses, this::loadPetData);
+    }
 
-        spinnerStatus.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
-            @Override
-            public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
-                filterPets();
+    /**
+     * Configures the species filter spinner with species.
+     */
+    private void setupSpeciesFilter() {
+        String[] species = {"All Species", "Dog", "Cat", "Bird", "Rabbit", "Fish", "Hamster"};
+        SpinnerUtils.setupStringFilterSpinner(requireContext(), binding.spinnerSpecies, species, this::loadPetData);
+    }
+
+    /**
+     * Configures the store filter spinner.
+     */
+    private void setupStoreFilter() {
+        SpinnerUtils.setupFilterSpinner(binding.spinnerStore, this::loadPetData);
+    }
+
+    /**
+     * Fetches store data to populate the store filter.
+     */
+    private void loadStoreData() {
+        storeViewModel.getAllStores(0, 100).observe(getViewLifecycleOwner(), resource -> {
+            if (resource.status == Resource.Status.SUCCESS && resource.data != null) {
+                storeList = resource.data.getContent();
+                SpinnerUtils.populateWhiteSpinner(requireContext(), binding.spinnerStore, storeList,
+                        StoreDTO::getStoreName, "All Stores", -1L, StoreDTO::getStoreId);
             }
-
-            @Override
-            public void onNothingSelected(AdapterView<?> parent) {}
         });
     }
 
-    // Helper function to filter pets based on search and status filter
-    private void filterPets() {
-        String query = etSearch.getText().toString().toLowerCase();
-        String selectedStatus = spinnerStatus.getSelectedItem().toString();
-        
-        filteredList.clear();
-        for (PetDTO p : petList) {
-            boolean matchesSearch = query.isEmpty() || 
-                                    p.getPetName().toLowerCase().contains(query) ||
-                                    p.getPetSpecies().toLowerCase().contains(query) ||
-                                    p.getPetBreed().toLowerCase().contains(query);
-            
-            boolean matchesStatus = selectedStatus.equals("All Statuses") || 
-                                    p.getPetStatus().equalsIgnoreCase(selectedStatus);
-
-            if (matchesSearch && matchesStatus) {
-                filteredList.add(p);
-            }
-        }
-        adapter.notifyDataSetChanged();
+    /**
+     * Sets up the SwipeRefreshLayout.
+     */
+    private void setupSwipeRefresh() {
+        binding.swipeRefreshPet.setOnRefreshListener(this::loadPetData);
     }
 
-    private void setupSwipeRefresh(View view) {
-        swipeRefreshLayout = view.findViewById(R.id.swipeRefreshPet);
-        swipeRefreshLayout.setOnRefreshListener(() -> {
-            loadPetData();
-        });
-    }
-
-    //Open pet profile
+    /**
+     * Navigates to the pet profile screen.
+     */
     private void openPetProfile(int position) {
-        PetProfileFragment profileFragment = new PetProfileFragment();
-
-        //Make a bundle to pass data to the profile fragment
         Bundle args = new Bundle();
-        PetDTO pet = filteredList.get(position);
-        args.putInt("petId", pet.getPetId().intValue());
-        args.putString("petName", pet.getPetName());
-        args.putString("petSpecies", pet.getPetSpecies());
-        args.putString("petBreed", pet.getPetBreed());
-        args.putInt("petAge", pet.getPetAge());
-        args.putString("petStatus", pet.getPetStatus());
-        
-        try {
-            args.putDouble("petPrice", Double.parseDouble(pet.getPetPrice()));
-        } catch (Exception e) {
-            args.putDouble("petPrice", 0.0);
-        }
-
-        //send the bundle to the profile fragment to display
-        profileFragment.setArguments(args);
-
-        //get ListFragment to load the the pet profile view
-        ListFragment listFragment = (ListFragment) getParentFragment();
-        if (listFragment != null) {
-            listFragment.loadFragment(profileFragment);
-        }
+        PetDTO pet = petList.get(position);
+        args.putLong("petId", pet.getPetId());
+        NavHostFragment.findNavController(this).navigate(R.id.nav_pet_profile, args);
     }
 
-    //Open the pet detail view for adding
-    private void openPetDetails(int position) {
-        PetDetailFragment detailFragment = new PetDetailFragment();
-
-        //get ListFragment to load the detail view
-        ListFragment listFragment = (ListFragment) getParentFragment();
-        if (listFragment != null) {
-            listFragment.loadFragment(detailFragment);
-        }
+    /**
+     * Navigates to the pet detail screen.
+     */
+    private void openPetDetails() {
+        NavHostFragment.findNavController(this).navigate(R.id.nav_pet_detail);
     }
 
-    // Called by PetAdapter when a row is clicked to open the details view
     @Override
     public void onPetClick(int position) {
         openPetProfile(position);
     }
 
-    // Helper function to get a list of all pets from the backend
-    private void loadPetData() {
-        if (swipeRefreshLayout != null) {
-            swipeRefreshLayout.setRefreshing(true);
+    @Override
+    public void onSelectionChanged(int selectedCount) {
+        if (bulkDeleteHandler != null) {
+            bulkDeleteHandler.onSelectionChanged(selectedCount);
         }
-        api.getAllPets(0, 100).enqueue(new Callback<PageResponse<PetDTO>>() {
-            @Override
-            public void onResponse(Call<PageResponse<PetDTO>> call, Response<PageResponse<PetDTO>> response) {
-                if (swipeRefreshLayout != null) {
-                    swipeRefreshLayout.setRefreshing(false);
-                }
-                if (response.isSuccessful() && response.body() != null) {
-                    petList.clear();
-                    petList.addAll(response.body().getContent());
-                    filterPets();
+    }
 
-                } else {
-                    Log.e("onResponse: ", response.message());
-                }
-            }
+    /**
+     * Fetches pet data from the server with all active filters.
+     */
+    private void loadPetData() {
+        String query = binding.etSearchPet.getText().toString().trim();
+        String status = binding.spinnerStatus.getSelectedItem() != null ? binding.spinnerStatus.getSelectedItem().toString() : "All Statuses";
+        String species = binding.spinnerSpecies.getSelectedItem() != null ? binding.spinnerSpecies.getSelectedItem().toString() : "All Species";
+        
+        Long storeId = null;
+        if (binding.spinnerStore.getSelectedItemPosition() > 0 && !storeList.isEmpty()) {
+            storeId = storeList.get(binding.spinnerStore.getSelectedItemPosition() - 1).getStoreId();
+        }
 
-            @Override
-            public void onFailure(Call<PageResponse<PetDTO>> call, Throwable t) {
-                if (swipeRefreshLayout != null) {
-                    swipeRefreshLayout.setRefreshing(false);
-                }
-                Toast.makeText(getContext(),
-                        "Failed to load pets", Toast.LENGTH_SHORT).show();
-                Log.e("onFailure: ", t.getMessage());
+        if (status.equals("All Statuses")) status = null;
+        if (species.equals("All Species")) species = null;
+
+        viewModel.getAllPets(0, 100, query, status, species, storeId, "petName").observe(getViewLifecycleOwner(), resource -> {
+            if (resource == null) return;
+            
+            switch (resource.status) {
+                case LOADING:
+                    binding.swipeRefreshPet.setRefreshing(true);
+                    break;
+                case SUCCESS:
+                    binding.swipeRefreshPet.setRefreshing(false);
+                    if (resource.data != null) {
+                        petList.clear();
+                        petList.addAll(resource.data.getContent());
+                        adapter.notifyDataSetChanged();
+                    }
+                    break;
+                case ERROR:
+                    binding.swipeRefreshPet.setRefreshing(false);
+                    Toast.makeText(getContext(), "Failed to load pets: " + resource.message, Toast.LENGTH_SHORT).show();
+                    Log.e("PetFragment", "Error loading pets: " + resource.message);
+                    break;
             }
         });
     }
 
-    //set up the recyclerview and adapter
-    private void setupRecyclerView(View view) {
-        RecyclerView recyclerView = view.findViewById(R.id.recyclerViewPets);
-        adapter = new PetAdapter(filteredList, this);
-        recyclerView.setLayoutManager(new LinearLayoutManager(getContext()));
-        recyclerView.setAdapter(adapter);
+    /**
+     * Initializes the RecyclerView.
+     */
+    private void setupRecyclerView() {
+        adapter = new PetAdapter(petList, this);
+        adapter.setBaseUrl(baseUrl);
+        binding.recyclerViewPets.setLayoutManager(new LinearLayoutManager(getContext()));
+        binding.recyclerViewPets.setAdapter(adapter);
     }
-}
+}

android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/ProductFragment.java

@@ -1,133 +1,226 @@
 package com.example.petstoremobile.fragments.listfragments;
 
 import android.os.Bundle;
-import android.text.*;
-import android.util.Log;
-import android.view.*;
-import android.widget.*;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 import androidx.fragment.app.Fragment;
+import androidx.lifecycle.ViewModelProvider;
+import androidx.navigation.fragment.NavHostFragment;
 import androidx.recyclerview.widget.LinearLayoutManager;
-import androidx.recyclerview.widget.RecyclerView;
-import androidx.swiperefreshlayout.widget.SwipeRefreshLayout;
+
+import android.text.Editable;
+import android.text.TextWatcher;
+import android.util.Log;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.Toast;
+
 import com.example.petstoremobile.R;
 import com.example.petstoremobile.adapters.ProductAdapter;
-import com.example.petstoremobile.api.RetrofitClient;
-import com.example.petstoremobile.dtos.PageResponse;
+import com.example.petstoremobile.databinding.FragmentProductBinding;
+import com.example.petstoremobile.dtos.CategoryDTO;
 import com.example.petstoremobile.dtos.ProductDTO;
 import com.example.petstoremobile.fragments.ListFragment;
-import com.example.petstoremobile.fragments.listfragments.detailfragments.ProductDetailFragment;
-import com.google.android.material.floatingactionbutton.FloatingActionButton;
-import java.util.*;
-import retrofit2.*;
+import com.example.petstoremobile.utils.Resource;
+import com.example.petstoremobile.utils.SpinnerUtils;
+import com.example.petstoremobile.viewmodels.ProductViewModel;
 
+import java.util.ArrayList;
+import java.util.List;
+
+import javax.inject.Inject;
+import javax.inject.Named;
+
+import dagger.hilt.android.AndroidEntryPoint;
+
+@AndroidEntryPoint
 public class ProductFragment extends Fragment implements ProductAdapter.OnProductClickListener {
 
+    private FragmentProductBinding binding;
     private List<ProductDTO> productList = new ArrayList<>();
-    private List<ProductDTO> filteredList = new ArrayList<>();
+    private List<CategoryDTO> categoryList = new ArrayList<>();
     private ProductAdapter adapter;
-    private SwipeRefreshLayout swipeRefresh;
-    private EditText etSearch;
+    private ProductViewModel viewModel;
 
+    @Inject @Named("baseUrl") String baseUrl;
+
+    /**
+     * Initializes the fragment and its associated ProductViewModel.
+     */
     @Override
-    public View onCreateView(LayoutInflater inflater, ViewGroup container,
+    public void onCreate(@Nullable Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        viewModel = new ViewModelProvider(this).get(ProductViewModel.class);
+    }
+
+    /**
+     * Sets up the fragment's UI components, including RecyclerView, search, and swipe-to-refresh.
+     */
+    @Override
+    public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
-        View view = inflater.inflate(R.layout.fragment_product, container, false);
+        binding = FragmentProductBinding.inflate(inflater, container, false);
 
-        setupRecyclerView(view);
-        setupSearch(view);
-        setupSwipeRefresh(view);
-        loadProducts();
+        setupRecyclerView();
+        setupSearch();
+        setupCategoryFilter();
+        setupSwipeRefresh();
+        setupFilterToggle();
 
-        FloatingActionButton fab = view.findViewById(R.id.fabAddProduct);
-        fab.setOnClickListener(v -> openDetail(-1));
+        binding.fabAddProduct.setOnClickListener(v -> openProductDetails(-1));
 
-        ImageButton hamburger = view.findViewById(R.id.btnHamburgerProduct);
-        hamburger.setOnClickListener(v -> {
-            ListFragment lf = (ListFragment) getParentFragment();
-            if (lf != null) lf.openDrawer();
-        });
-
-        return view;
-    }
-
-    private void setupRecyclerView(View view) {
-        RecyclerView rv = view.findViewById(R.id.recyclerViewProducts);
-        adapter = new ProductAdapter(filteredList, this);
-        rv.setLayoutManager(new LinearLayoutManager(getContext()));
-        rv.setAdapter(adapter);
-    }
-
-    private void setupSearch(View view) {
-        etSearch = view.findViewById(R.id.etSearchProduct);
-        etSearch.addTextChangedListener(new TextWatcher() {
-            public void beforeTextChanged(CharSequence s, int a, int b, int c) {}
-            public void afterTextChanged(Editable s) {}
-            public void onTextChanged(CharSequence s, int a, int b, int c) {
-                filter(s.toString());
-            }
-        });
-    }
-
-    private void setupSwipeRefresh(View view) {
-        swipeRefresh = view.findViewById(R.id.swipeRefreshProduct);
-        swipeRefresh.setOnRefreshListener(this::loadProducts);
-    }
-
-    private void filter(String query) {
-        filteredList.clear();
-        if (query.isEmpty()) {
-            filteredList.addAll(productList);
-        } else {
-            String lower = query.toLowerCase();
-            for (ProductDTO p : productList) {
-                if ((p.getProdName() != null && p.getProdName().toLowerCase().contains(lower))
-                        || (p.getCategoryName() != null && p.getCategoryName().toLowerCase().contains(lower))) {
-                    filteredList.add(p);
+        binding.btnHamburgerProduct.setOnClickListener(v -> {
+            Fragment parent = getParentFragment();
+            if (parent != null) {
+                Fragment grandParent = parent.getParentFragment();
+                if (grandParent instanceof ListFragment) {
+                    ((ListFragment) grandParent).openDrawer();
                 }
             }
-        }
-        adapter.notifyDataSetChanged();
-    }
+        });
 
-    private void loadProducts() {
-        if (swipeRefresh != null) swipeRefresh.setRefreshing(true);
-        RetrofitClient.getProductApi(requireContext()).getAllProducts(null, 0, 100)
-                .enqueue(new Callback<PageResponse<ProductDTO>>() {
-                    public void onResponse(Call<PageResponse<ProductDTO>> c,
-                                           Response<PageResponse<ProductDTO>> r) {
-                        if (swipeRefresh != null) swipeRefresh.setRefreshing(false);
-                        if (r.isSuccessful() && r.body() != null) {
-                            productList.clear();
-                            productList.addAll(r.body().getContent());
-                            filter(etSearch != null ? etSearch.getText().toString() : "");
-                        } else {
-                            Toast.makeText(getContext(), "Failed to load products",
-                                    Toast.LENGTH_SHORT).show();
-                        }
-                    }
-                    public void onFailure(Call<PageResponse<ProductDTO>> c, Throwable t) {
-                        if (swipeRefresh != null) swipeRefresh.setRefreshing(false);
-                        Log.e("ProductFragment", t.getMessage());
-                    }
-                });
-    }
-
-    private void openDetail(int position) {
-        ProductDetailFragment detail = new ProductDetailFragment();
-        Bundle args = new Bundle();
-        if (position != -1) {
-            ProductDTO p = filteredList.get(position);
-            args.putLong("prodId", p.getProdId());
-            args.putString("prodName", p.getProdName());
-            args.putString("prodDesc", p.getProdDesc() != null ? p.getProdDesc() : "");
-            args.putString("prodPrice", p.getProdPrice() != null ? p.getProdPrice().toString() : "");
-            args.putLong("categoryId", p.getCategoryId() != null ? p.getCategoryId() : -1);
-        }
-        detail.setArguments(args);
-        ListFragment lf = (ListFragment) getParentFragment();
-        if (lf != null) lf.loadFragment(detail);
+        return binding.getRoot();
     }
 
     @Override
-    public void onProductClick(int position) { openDetail(position); }
-}
+    public void onDestroyView() {
+        super.onDestroyView();
+        binding = null;
+    }
+
+    /**
+     * Reloads data every time the fragment becomes visible.
+     */
+    @Override
+    public void onResume() {
+        super.onResume();
+        loadProductData();
+        loadCategoryData();
+    }
+
+    /**
+     * Sets up the filter toggle button to show/hide the filter layout.
+     */
+    private void setupFilterToggle() {
+        binding.btnToggleFilter.setOnClickListener(v -> {
+            if (binding.layoutFilter.getVisibility() == View.GONE) {
+                binding.layoutFilter.setVisibility(View.VISIBLE);
+                binding.btnToggleFilter.setImageResource(android.R.drawable.ic_menu_close_clear_cancel);
+            } else {
+                binding.layoutFilter.setVisibility(View.GONE);
+                binding.btnToggleFilter.setImageResource(android.R.drawable.ic_menu_search);
+
+                // Reset filters when closing
+                binding.etSearchProduct.setText("");
+                binding.spinnerCategory.setSelection(0);
+            }
+        });
+    }
+
+    /**
+     * Configures the search bar for triggering data load from backend.
+     */
+    private void setupSearch() {
+        binding.etSearchProduct.addTextChangedListener(new TextWatcher() {
+            @Override public void beforeTextChanged(CharSequence s, int start, int count, int after) {}
+            @Override public void onTextChanged(CharSequence s, int start, int before, int count) {
+                loadProductData();
+            }
+            @Override public void afterTextChanged(Editable s) {}
+        });
+    }
+
+    /**
+     * Configures the category filter spinner.
+     */
+    private void setupCategoryFilter() {
+        SpinnerUtils.setupFilterSpinner(binding.spinnerCategory, this::loadProductData);
+    }
+
+    /**
+     * Fetches category data to populate the category filter.
+     */
+    private void loadCategoryData() {
+        viewModel.getAllCategories(0, 100).observe(getViewLifecycleOwner(), resource -> {
+            if (resource.status == Resource.Status.SUCCESS && resource.data != null) {
+                categoryList = resource.data.getContent();
+                SpinnerUtils.populateWhiteSpinner(requireContext(), binding.spinnerCategory, categoryList,
+                        CategoryDTO::getCategoryName, "All Categories", -1L, CategoryDTO::getCategoryId);
+            }
+        });
+    }
+
+    /**
+     * Sets up the SwipeRefreshLayout.
+     */
+    private void setupSwipeRefresh() {
+        binding.swipeRefreshProduct.setOnRefreshListener(this::loadProductData);
+    }
+
+    /**
+     * Navigates to the product detail screen.
+     */
+    private void openProductDetails(int position) {
+        Bundle args = new Bundle();
+        if (position != -1) {
+            ProductDTO product = productList.get(position);
+            args.putLong("prodId", product.getProdId());
+        }
+        NavHostFragment.findNavController(this).navigate(R.id.nav_product_detail, args);
+    }
+
+    @Override
+    public void onProductClick(int position) {
+        openProductDetails(position);
+    }
+
+    /**
+     * Fetches product data from the server with search query, category, and sorting.
+     */
+    private void loadProductData() {
+        String query = binding.etSearchProduct.getText().toString().trim();
+        if (query.isEmpty()) query = null;
+
+        Long categoryId = null;
+        if (binding.spinnerCategory.getSelectedItemPosition() > 0 && !categoryList.isEmpty()) {
+            categoryId = categoryList.get(binding.spinnerCategory.getSelectedItemPosition() - 1).getCategoryId();
+        }
+
+        viewModel.getAllProducts(query, categoryId, 0, 100, "prodName").observe(getViewLifecycleOwner(), resource -> {
+            if (resource == null) return;
+
+            switch (resource.status) {
+                case LOADING:
+                    binding.swipeRefreshProduct.setRefreshing(true);
+                    break;
+                case SUCCESS:
+                    binding.swipeRefreshProduct.setRefreshing(false);
+                    if (resource.data != null) {
+                        productList.clear();
+                        productList.addAll(resource.data.getContent());
+                        adapter.notifyDataSetChanged();
+                    }
+                    break;
+                case ERROR:
+                    binding.swipeRefreshProduct.setRefreshing(false);
+                    if (getContext() != null) {
+                        Toast.makeText(getContext(), "Failed to load products: " + resource.message, Toast.LENGTH_SHORT).show();
+                    }
+                    Log.e("ProductFragment", "Error loading products: " + resource.message);
+                    break;
+            }
+        });
+    }
+
+    /**
+     * Initializes the RecyclerView.
+     */
+    private void setupRecyclerView() {
+        adapter = new ProductAdapter(productList, this);
+        adapter.setBaseUrl(baseUrl);
+        binding.recyclerViewProducts.setLayoutManager(new LinearLayoutManager(getContext()));
+        binding.recyclerViewProducts.setAdapter(adapter);
+    }
+}

android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/ProductSupplierFragment.java

@@ -1,134 +1,278 @@
 package com.example.petstoremobile.fragments.listfragments;
 
 import android.os.Bundle;
-import android.text.*;
+import android.text.Editable;
+import android.text.TextWatcher;
 import android.util.Log;
-import android.view.*;
-import android.widget.*;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.Toast;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 import androidx.fragment.app.Fragment;
+import androidx.lifecycle.ViewModelProvider;
+import androidx.navigation.fragment.NavHostFragment;
 import androidx.recyclerview.widget.LinearLayoutManager;
-import androidx.recyclerview.widget.RecyclerView;
-import androidx.swiperefreshlayout.widget.SwipeRefreshLayout;
+
 import com.example.petstoremobile.R;
 import com.example.petstoremobile.adapters.ProductSupplierAdapter;
-import com.example.petstoremobile.api.RetrofitClient;
-import com.example.petstoremobile.dtos.PageResponse;
+import com.example.petstoremobile.databinding.FragmentProductSupplierBinding;
+import com.example.petstoremobile.dtos.ProductDTO;
 import com.example.petstoremobile.dtos.ProductSupplierDTO;
+import com.example.petstoremobile.dtos.SupplierDTO;
 import com.example.petstoremobile.fragments.ListFragment;
-import com.example.petstoremobile.fragments.listfragments.detailfragments.ProductSupplierDetailFragment;
-import com.google.android.material.floatingactionbutton.FloatingActionButton;
-import java.util.*;
-import retrofit2.*;
+import com.example.petstoremobile.utils.BulkDeleteHandler;
+import com.example.petstoremobile.utils.Resource;
+import com.example.petstoremobile.utils.SpinnerUtils;
+import com.example.petstoremobile.viewmodels.ProductSupplierViewModel;
+import com.example.petstoremobile.viewmodels.ProductViewModel;
+import com.example.petstoremobile.viewmodels.SupplierViewModel;
 
+import java.util.ArrayList;
+import java.util.List;
+
+import dagger.hilt.android.AndroidEntryPoint;
+
+@AndroidEntryPoint
 public class ProductSupplierFragment extends Fragment
         implements ProductSupplierAdapter.OnProductSupplierClickListener {
 
+    private FragmentProductSupplierBinding binding;
     private List<ProductSupplierDTO> psList = new ArrayList<>();
-    private List<ProductSupplierDTO> filteredList = new ArrayList<>();
+    private List<ProductDTO> productList = new ArrayList<>();
+    private List<SupplierDTO> supplierList = new ArrayList<>();
+    
     private ProductSupplierAdapter adapter;
-    private SwipeRefreshLayout swipeRefresh;
-    private EditText etSearch;
+    private ProductSupplierViewModel viewModel;
+    private ProductViewModel productViewModel;
+    private SupplierViewModel supplierViewModel;
+    private BulkDeleteHandler bulkDeleteHandler;
 
+    /**
+     * Initializes the fragment and its associated ViewModels.
+     */
     @Override
-    public View onCreateView(LayoutInflater inflater, ViewGroup container,
+    public void onCreate(@Nullable Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        viewModel = new ViewModelProvider(this).get(ProductSupplierViewModel.class);
+        productViewModel = new ViewModelProvider(this).get(ProductViewModel.class);
+        supplierViewModel = new ViewModelProvider(this).get(SupplierViewModel.class);
+    }
+
+    /**
+     * Sets up the fragment's UI components, including the RecyclerView, search, and swipe-to-refresh.
+     */
+    @Override
+    public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
-        View view = inflater.inflate(R.layout.fragment_product_supplier, container, false);
+        binding = FragmentProductSupplierBinding.inflate(inflater, container, false);
 
-        setupRecyclerView(view);
-        setupSearch(view);
-        setupSwipeRefresh(view);
-        loadData();
+        setupRecyclerView();
+        setupSearch();
+        setupProductFilter();
+        setupSupplierFilter();
+        setupSwipeRefresh();
+        setupFilterToggle();
+        setupBulkDelete();
 
-        FloatingActionButton fab = view.findViewById(R.id.fabAddPS);
-        fab.setOnClickListener(v -> openDetail(-1));
+        binding.fabAddPS.setOnClickListener(v -> openDetail(-1));
 
-        ImageButton hamburger = view.findViewById(R.id.btnHamburgerPS);
-        hamburger.setOnClickListener(v -> {
-            ListFragment lf = (ListFragment) getParentFragment();
-            if (lf != null) lf.openDrawer();
-        });
-
-        return view;
-    }
-
-    private void setupRecyclerView(View view) {
-        RecyclerView rv = view.findViewById(R.id.recyclerViewPS);
-        adapter = new ProductSupplierAdapter(filteredList, this);
-        rv.setLayoutManager(new LinearLayoutManager(getContext()));
-        rv.setAdapter(adapter);
-    }
-
-    private void setupSearch(View view) {
-        etSearch = view.findViewById(R.id.etSearchPS);
-        etSearch.addTextChangedListener(new TextWatcher() {
-            public void beforeTextChanged(CharSequence s, int a, int b, int c) {}
-            public void afterTextChanged(Editable s) {}
-            public void onTextChanged(CharSequence s, int a, int b, int c) {
-                filter(s.toString());
-            }
-        });
-    }
-
-    private void setupSwipeRefresh(View view) {
-        swipeRefresh = view.findViewById(R.id.swipeRefreshPS);
-        swipeRefresh.setOnRefreshListener(this::loadData);
-    }
-
-    private void filter(String query) {
-        filteredList.clear();
-        if (query.isEmpty()) {
-            filteredList.addAll(psList);
-        } else {
-            String lower = query.toLowerCase();
-            for (ProductSupplierDTO ps : psList) {
-                if ((ps.getProductName() != null && ps.getProductName().toLowerCase().contains(lower))
-                        || (ps.getSupplierName() != null && ps.getSupplierName().toLowerCase().contains(lower))) {
-                    filteredList.add(ps);
+        binding.btnHamburgerPS.setOnClickListener(v -> {
+            Fragment parent = getParentFragment();
+            if (parent != null) {
+                Fragment grandParent = parent.getParentFragment();
+                if (grandParent instanceof ListFragment) {
+                    ((ListFragment) grandParent).openDrawer();
                 }
             }
-        }
-        adapter.notifyDataSetChanged();
+        });
+
+        return binding.getRoot();
     }
 
-    private void loadData() {
-        if (swipeRefresh != null) swipeRefresh.setRefreshing(true);
-        RetrofitClient.getProductSupplierApi(requireContext()).getAllProductSuppliers(0, 100)
-                .enqueue(new Callback<PageResponse<ProductSupplierDTO>>() {
-                    public void onResponse(Call<PageResponse<ProductSupplierDTO>> c,
-                                           Response<PageResponse<ProductSupplierDTO>> r) {
-                        if (swipeRefresh != null) swipeRefresh.setRefreshing(false);
-                        if (r.isSuccessful() && r.body() != null) {
-                            psList.clear();
-                            psList.addAll(r.body().getContent());
-                            filter(etSearch != null ? etSearch.getText().toString() : "");
-                        } else {
-                            Toast.makeText(getContext(), "Failed to load",
-                                    Toast.LENGTH_SHORT).show();
-                        }
-                    }
-                    public void onFailure(Call<PageResponse<ProductSupplierDTO>> c, Throwable t) {
-                        if (swipeRefresh != null) swipeRefresh.setRefreshing(false);
-                        Log.e("PSFragment", t.getMessage());
-                    }
-                });
-    }
-
-    private void openDetail(int position) {
-        ProductSupplierDetailFragment detail = new ProductSupplierDetailFragment();
-        Bundle args = new Bundle();
-        if (position != -1) {
-            ProductSupplierDTO ps = filteredList.get(position);
-            args.putLong("productId", ps.getProductId());
-            args.putLong("supplierId", ps.getSupplierId());
-            args.putString("productName", ps.getProductName());
-            args.putString("supplierName", ps.getSupplierName());
-            args.putString("cost", ps.getCost() != null ? ps.getCost().toString() : "");
-        }
-        detail.setArguments(args);
-        ListFragment lf = (ListFragment) getParentFragment();
-        if (lf != null) lf.loadFragment(detail);
+    private void setupBulkDelete() {
+        bulkDeleteHandler = new BulkDeleteHandler(
+                this,
+                binding.layoutBulkDelete,
+                binding.tvSelectionCount,
+                binding.btnBulkDelete,
+                adapter,
+                "relationship",
+                viewModel::bulkDeleteProductSuppliers,
+                this::loadData
+        );
     }
 
+    @Override
+    public void onDestroyView() {
+        super.onDestroyView();
+        binding = null;
+    }
+
+    /**
+     * Reloads data every time the fragment becomes visible.
+     */
+    @Override
+    public void onResume() {
+        super.onResume();
+        loadData();
+        loadFilterData();
+    }
+
+    /**
+     * Sets up the filter toggle button to show/hide the filter layout.
+     */
+    private void setupFilterToggle() {
+        binding.btnToggleFilter.setOnClickListener(v -> {
+            if (binding.layoutFilter.getVisibility() == View.GONE) {
+                binding.layoutFilter.setVisibility(View.VISIBLE);
+                binding.btnToggleFilter.setImageResource(android.R.drawable.ic_menu_close_clear_cancel);
+            } else {
+                binding.layoutFilter.setVisibility(View.GONE);
+                binding.btnToggleFilter.setImageResource(android.R.drawable.ic_menu_search);
+
+                // Reset filters when closing
+                binding.etSearchPS.setText("");
+                binding.spinnerProduct.setSelection(0);
+                binding.spinnerSupplier.setSelection(0);
+            }
+        });
+    }
+
+    /**
+     * Initializes the RecyclerView with a layout manager and adapter for product-supplier data.
+     */
+    private void setupRecyclerView() {
+        adapter = new ProductSupplierAdapter(psList, this);
+        binding.recyclerViewPS.setLayoutManager(new LinearLayoutManager(getContext()));
+        binding.recyclerViewPS.setAdapter(adapter);
+    }
+
+    /**
+     * Configures the search bar for filtering.
+     */
+    private void setupSearch() {
+        binding.etSearchPS.addTextChangedListener(new TextWatcher() {
+            @Override public void beforeTextChanged(CharSequence s, int start, int count, int after) {}
+            @Override public void onTextChanged(CharSequence s, int start, int before, int count) {
+                loadData();
+            }
+            @Override public void afterTextChanged(Editable s) {}
+        });
+    }
+
+    /**
+     * Configures the product filter spinner.
+     */
+    private void setupProductFilter() {
+        SpinnerUtils.setupFilterSpinner(binding.spinnerProduct, this::loadData);
+    }
+
+    /**
+     * Configures the supplier filter spinner.
+     */
+    private void setupSupplierFilter() {
+        SpinnerUtils.setupFilterSpinner(binding.spinnerSupplier, this::loadData);
+    }
+
+    /**
+     * Fetches products and suppliers to populate the filters.
+     */
+    private void loadFilterData() {
+        productViewModel.getAllProducts(null, null, 0, 100, "prodName").observe(getViewLifecycleOwner(), resource -> {
+            if (resource.status == Resource.Status.SUCCESS && resource.data != null) {
+                productList = resource.data.getContent();
+                SpinnerUtils.populateWhiteSpinner(requireContext(), binding.spinnerProduct, productList,
+                        ProductDTO::getProdName, "All Products", -1L, ProductDTO::getProdId);
+            }
+        });
+
+        supplierViewModel.getAllSuppliers(0, 100, null, "supCompany").observe(getViewLifecycleOwner(), resource -> {
+            if (resource.status == Resource.Status.SUCCESS && resource.data != null) {
+                supplierList = resource.data.getContent();
+                SpinnerUtils.populateWhiteSpinner(requireContext(), binding.spinnerSupplier, supplierList,
+                        SupplierDTO::getSupCompany, "All Suppliers", -1L, SupplierDTO::getSupId);
+            }
+        });
+    }
+
+    /**
+     * Sets up the SwipeRefreshLayout to allow manual reloading of product-supplier data.
+     */
+    private void setupSwipeRefresh() {
+        binding.swipeRefreshPS.setOnRefreshListener(this::loadData);
+    }
+
+    /**
+     * Fetches product-supplier data from the server through the ViewModel with search query and filters.
+     */
+    private void loadData() {
+        String query = binding.etSearchPS.getText().toString().trim();
+        if (query.isEmpty()) query = null;
+
+        Long productId = null;
+        if (binding.spinnerProduct.getSelectedItemPosition() > 0 && !productList.isEmpty()) {
+            productId = productList.get(binding.spinnerProduct.getSelectedItemPosition() - 1).getProdId();
+        }
+
+        Long supplierId = null;
+        if (binding.spinnerSupplier.getSelectedItemPosition() > 0 && !supplierList.isEmpty()) {
+            supplierId = supplierList.get(binding.spinnerSupplier.getSelectedItemPosition() - 1).getSupId();
+        }
+
+        viewModel.getAllProductSuppliers(0, 100, query, productId, supplierId, "productName").observe(getViewLifecycleOwner(), resource -> {
+            if (resource == null) return;
+
+            // Check the status to see if the resource is loaded and display the data
+            switch (resource.status) {
+                case LOADING:
+                    // Show loading indicator
+                    binding.swipeRefreshPS.setRefreshing(true);
+                    break;
+                case SUCCESS:
+                    // Hide loading indicator and display data
+                    binding.swipeRefreshPS.setRefreshing(false);
+                    if (resource.data != null) {
+                        psList.clear();
+                        psList.addAll(resource.data.getContent());
+                        adapter.notifyDataSetChanged();
+                    }
+                    break;
+                case ERROR:
+                    // Hide loading indicator and toast error message
+                    binding.swipeRefreshPS.setRefreshing(false);
+                    Toast.makeText(getContext(), "Failed to load: " + resource.message, Toast.LENGTH_SHORT).show();
+                    Log.e("PSFragment", "Error loading: " + resource.message);
+                    break;
+            }
+        });
+    }
+
+    /**
+     * Navigates to the product-supplier detail screen for a specific item or to add a new record.
+     */
+    private void openDetail(int position) {
+        Bundle args = new Bundle();
+        if (position != -1) {
+            ProductSupplierDTO ps = psList.get(position);
+            args.putLong("productId", ps.getProductId());
+            args.putLong("supplierId", ps.getSupplierId());
+        }
+        NavHostFragment.findNavController(this).navigate(R.id.nav_product_supplier_detail, args);
+    }
+
+    /**
+     * Handles item click in the product-supplier list.
+     */
     @Override
     public void onProductSupplierClick(int position) { openDetail(position); }
-}
+
+    @Override
+    public void onSelectionChanged(int count) {
+        if (bulkDeleteHandler != null) {
+            bulkDeleteHandler.onSelectionChanged(count);
+        }
+    }
+}

android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/PurchaseOrderFragment.java

@@ -1,139 +1,224 @@
 package com.example.petstoremobile.fragments.listfragments;
 
 import android.os.Bundle;
-import android.text.*;
+import android.text.Editable;
+import android.text.TextWatcher;
 import android.util.Log;
-import android.view.*;
-import android.widget.*;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.Toast;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 import androidx.fragment.app.Fragment;
+import androidx.lifecycle.ViewModelProvider;
+import androidx.navigation.fragment.NavHostFragment;
 import androidx.recyclerview.widget.LinearLayoutManager;
-import androidx.recyclerview.widget.RecyclerView;
-import androidx.swiperefreshlayout.widget.SwipeRefreshLayout;
+
 import com.example.petstoremobile.R;
 import com.example.petstoremobile.adapters.PurchaseOrderAdapter;
-import com.example.petstoremobile.api.RetrofitClient;
-import com.example.petstoremobile.dtos.PageResponse;
+import com.example.petstoremobile.databinding.FragmentPurchaseOrderBinding;
 import com.example.petstoremobile.dtos.PurchaseOrderDTO;
+import com.example.petstoremobile.dtos.StoreDTO;
 import com.example.petstoremobile.fragments.ListFragment;
-import com.example.petstoremobile.fragments.listfragments.detailfragments.PurchaseOrderDetailFragment;
-import java.util.*;
-import retrofit2.*;
+import com.example.petstoremobile.utils.Resource;
+import com.example.petstoremobile.utils.SpinnerUtils;
+import com.example.petstoremobile.viewmodels.PurchaseOrderViewModel;
+import com.example.petstoremobile.viewmodels.StoreViewModel;
 
+import java.util.ArrayList;
+import java.util.List;
+
+import dagger.hilt.android.AndroidEntryPoint;
+
+@AndroidEntryPoint
 public class PurchaseOrderFragment extends Fragment
         implements PurchaseOrderAdapter.OnPurchaseOrderClickListener {
 
+    private FragmentPurchaseOrderBinding binding;
     private List<PurchaseOrderDTO> poList = new ArrayList<>();
-    private List<PurchaseOrderDTO> filteredList = new ArrayList<>();
+    private List<StoreDTO> storeList = new ArrayList<>();
     private PurchaseOrderAdapter adapter;
-    private SwipeRefreshLayout swipeRefresh;
-    private EditText etSearch;
+    private PurchaseOrderViewModel viewModel;
+    private StoreViewModel storeViewModel;
 
+    /**
+     * Initializes the fragment and its associated ViewModels.
+     */
     @Override
-    public View onCreateView(LayoutInflater inflater, ViewGroup container,
+    public void onCreate(@Nullable Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        viewModel = new ViewModelProvider(this).get(PurchaseOrderViewModel.class);
+        storeViewModel = new ViewModelProvider(this).get(StoreViewModel.class);
+    }
+
+    /**
+     * Sets up the fragment's UI components, including RecyclerView, filters, and swipe-to-refresh.
+     */
+    @Override
+    public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
-        View view = inflater.inflate(R.layout.fragment_purchase_order, container, false);
+        binding = FragmentPurchaseOrderBinding.inflate(inflater, container, false);
 
-        setupRecyclerView(view);
-        setupSearch(view);
-        setupSwipeRefresh(view);
-        loadData();
+        setupRecyclerView();
+        setupSearch();
+        setupStoreFilter();
+        setupSwipeRefresh();
+        setupFilterToggle();
 
-        ImageButton hamburger = view.findViewById(R.id.btnHamburgerPO);
-        hamburger.setOnClickListener(v -> {
-            ListFragment lf = (ListFragment) getParentFragment();
-            if (lf != null)
-                lf.openDrawer();
-        });
-
-        return view;
-    }
-
-    private void setupRecyclerView(View view) {
-        RecyclerView rv = view.findViewById(R.id.recyclerViewPO);
-        adapter = new PurchaseOrderAdapter(filteredList, this);
-        rv.setLayoutManager(new LinearLayoutManager(getContext()));
-        rv.setAdapter(adapter);
-    }
-
-    private void setupSearch(View view) {
-        etSearch = view.findViewById(R.id.etSearchPO);
-        etSearch.addTextChangedListener(new TextWatcher() {
-            public void beforeTextChanged(CharSequence s, int a, int b, int c) {
-            }
-
-            public void afterTextChanged(Editable s) {
-            }
-
-            public void onTextChanged(CharSequence s, int a, int b, int c) {
-                filter(s.toString());
-            }
-        });
-    }
-
-    private void setupSwipeRefresh(View view) {
-        swipeRefresh = view.findViewById(R.id.swipeRefreshPO);
-        swipeRefresh.setOnRefreshListener(this::loadData);
-    }
-
-    private void filter(String query) {
-        filteredList.clear();
-        if (query.isEmpty()) {
-            filteredList.addAll(poList);
-        } else {
-            String lower = query.toLowerCase();
-            for (PurchaseOrderDTO po : poList) {
-                if ((po.getSupplierName() != null && po.getSupplierName().toLowerCase().contains(lower))
-                        || (po.getStatus() != null && po.getStatus().toLowerCase().contains(lower))) {
-                    filteredList.add(po);
+        binding.btnHamburgerPO.setOnClickListener(v -> {
+            Fragment parent = getParentFragment();
+            if (parent != null) {
+                Fragment grandParent = parent.getParentFragment();
+                if (grandParent instanceof ListFragment) {
+                    ((ListFragment) grandParent).openDrawer();
                 }
             }
-        }
-        adapter.notifyDataSetChanged();
+        });
+
+        return binding.getRoot();
     }
 
+    @Override
+    public void onDestroyView() {
+        super.onDestroyView();
+        binding = null;
+    }
+
+    /**
+     * Reloads data every time the fragment becomes visible.
+     */
+    @Override
+    public void onResume() {
+        super.onResume();
+        loadData();
+        loadStoreData();
+    }
+
+    /**
+     * Sets up the filter toggle button to show/hide the filter layout.
+     */
+    private void setupFilterToggle() {
+        binding.btnToggleFilter.setOnClickListener(v -> {
+            if (binding.layoutFilter.getVisibility() == View.GONE) {
+                binding.layoutFilter.setVisibility(View.VISIBLE);
+                binding.btnToggleFilter.setImageResource(android.R.drawable.ic_menu_close_clear_cancel);
+            } else {
+                binding.layoutFilter.setVisibility(View.GONE);
+                binding.btnToggleFilter.setImageResource(android.R.drawable.ic_menu_search);
+
+                // Reset filters when closing
+                binding.etSearchPO.setText("");
+                binding.spinnerStore.setSelection(0);
+            }
+        });
+    }
+
+    /**
+     * Configures the search bar for filtering.
+     */
+    private void setupSearch() {
+        binding.etSearchPO.addTextChangedListener(new TextWatcher() {
+            @Override public void beforeTextChanged(CharSequence s, int start, int count, int after) {}
+            @Override public void onTextChanged(CharSequence s, int start, int before, int count) {
+                loadData();
+            }
+            @Override public void afterTextChanged(Editable s) {}
+        });
+    }
+
+    /**
+     * Configures the store filter spinner.
+     */
+    private void setupStoreFilter() {
+        SpinnerUtils.setupFilterSpinner(binding.spinnerStore, this::loadData);
+    }
+
+    /**
+     * Fetches store data to populate the store filter.
+     */
+    private void loadStoreData() {
+        storeViewModel.getAllStores(0, 100).observe(getViewLifecycleOwner(), resource -> {
+            if (resource.status == Resource.Status.SUCCESS && resource.data != null) {
+                storeList = resource.data.getContent();
+                SpinnerUtils.populateWhiteSpinner(requireContext(), binding.spinnerStore, storeList,
+                        StoreDTO::getStoreName, "All Stores", -1L, StoreDTO::getStoreId);
+            }
+        });
+    }
+
+    /**
+     * Initializes the RecyclerView with a layout manager and adapter.
+     */
+    private void setupRecyclerView() {
+        adapter = new PurchaseOrderAdapter(poList, this);
+        binding.recyclerViewPO.setLayoutManager(new LinearLayoutManager(getContext()));
+        binding.recyclerViewPO.setAdapter(adapter);
+    }
+
+    /**
+     * Sets up the SwipeRefreshLayout to allow manual reloading of purchase order data.
+     */
+    private void setupSwipeRefresh() {
+        binding.swipeRefreshPO.setOnRefreshListener(this::loadData);
+    }
+
+    /**
+     * Fetches purchase order data from the server with active filters and updates the UI.
+     */
     private void loadData() {
-        if (swipeRefresh != null)
-            swipeRefresh.setRefreshing(true);
-        RetrofitClient.getPurchaseOrderApi(requireContext()).getAllPurchaseOrders(0, 100)
-                .enqueue(new Callback<PageResponse<PurchaseOrderDTO>>() {
-                    public void onResponse(Call<PageResponse<PurchaseOrderDTO>> c,
-                                           Response<PageResponse<PurchaseOrderDTO>> r) {
-                        if (swipeRefresh != null)
-                            swipeRefresh.setRefreshing(false);
-                        if (r.isSuccessful() && r.body() != null) {
-                            poList.clear();
-                            poList.addAll(r.body().getContent());
-                            filter(etSearch != null ? etSearch.getText().toString() : "");
-                        } else {
-                            Toast.makeText(getContext(), "Failed to load purchase orders",
-                                    Toast.LENGTH_SHORT).show();
-                        }
-                    }
+        String query = binding.etSearchPO != null ? binding.etSearchPO.getText().toString().trim() : "";
+        if (query.isEmpty()) query = null;
 
-                    public void onFailure(Call<PageResponse<PurchaseOrderDTO>> c, Throwable t) {
-                        if (swipeRefresh != null)
-                            swipeRefresh.setRefreshing(false);
-                        Log.e("POFragment", t.getMessage());
+        Long storeId = null;
+        if (binding.spinnerStore.getSelectedItemPosition() > 0 && !storeList.isEmpty()) {
+            storeId = storeList.get(binding.spinnerStore.getSelectedItemPosition() - 1).getStoreId();
+        }
+
+        viewModel.getAllPurchaseOrders(0, 100, query, storeId, "purchaseOrderId,desc").observe(getViewLifecycleOwner(), resource -> {
+            if (resource == null) return;
+
+            // Check the status to see if the resource is loaded and display the data
+            switch (resource.status) {
+                case LOADING:
+                    // Show loading indicator
+                    binding.swipeRefreshPO.setRefreshing(true);
+                    break;
+                case SUCCESS:
+                    // Hide loading indicator and display data
+                    binding.swipeRefreshPO.setRefreshing(false);
+                    if (resource.data != null) {
+                        poList.clear();
+                        poList.addAll(resource.data.getContent());
+                        adapter.notifyDataSetChanged();
                     }
-                });
+                    break;
+                case ERROR:
+                    // Hide loading indicator and toast error message
+                    binding.swipeRefreshPO.setRefreshing(false);
+                    Toast.makeText(getContext(), "Failed to load purchase orders: " + resource.message, Toast.LENGTH_SHORT).show();
+                    Log.e("POFragment", "Error loading purchase orders: " + resource.message);
+                    break;
+            }
+        });
     }
 
+    /**
+     * Navigates to the purchase order detail screen for a specific record.
+     */
     private void openDetail(int position) {
-        PurchaseOrderDetailFragment detail = new PurchaseOrderDetailFragment();
         Bundle args = new Bundle();
-        PurchaseOrderDTO po = filteredList.get(position);
+        PurchaseOrderDTO po = poList.get(position);
         args.putLong("purchaseOrderId", po.getPurchaseOrderId());
-        args.putString("supplierName", po.getSupplierName());
-        args.putString("orderDate", po.getOrderDate());
-        args.putString("status", po.getStatus());
-        detail.setArguments(args);
-        ListFragment lf = (ListFragment) getParentFragment();
-        if (lf != null)
-            lf.loadFragment(detail);
+        NavHostFragment.findNavController(this).navigate(R.id.nav_purchase_order_detail, args);
     }
 
+    /**
+     * Handles item click in the purchase order list.
+     */
     @Override
     public void onPurchaseOrderClick(int position) {
         openDetail(position);
     }
-}
+}

android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/SaleFragment.java

@@ -1,97 +1,97 @@
 package com.example.petstoremobile.fragments.listfragments;
 
 import android.os.Bundle;
-import android.text.*;
-import android.util.Log;
-import android.view.*;
-import android.widget.*;
+import androidx.annotation.NonNull;
 import androidx.fragment.app.Fragment;
+import androidx.navigation.fragment.NavHostFragment;
 import androidx.recyclerview.widget.LinearLayoutManager;
-import androidx.recyclerview.widget.RecyclerView;
-import androidx.swiperefreshlayout.widget.SwipeRefreshLayout;
+import android.text.Editable;
+import android.text.TextWatcher;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+
 import com.example.petstoremobile.R;
 import com.example.petstoremobile.adapters.SaleAdapter;
-import com.example.petstoremobile.api.RetrofitClient;
-import com.example.petstoremobile.dtos.PageResponse;
-import com.example.petstoremobile.dtos.SaleDTO;
+import com.example.petstoremobile.api.SaleApi;
+import com.example.petstoremobile.databinding.FragmentSaleBinding;
 import com.example.petstoremobile.fragments.ListFragment;
-import com.example.petstoremobile.fragments.listfragments.detailfragments.SaleDetailFragment;
-import com.google.android.material.floatingactionbutton.FloatingActionButton;
-import com.example.petstoremobile.fragments.listfragments.detailfragments.RefundFragment;
-import java.util.*;
-import retrofit2.*;
+import com.example.petstoremobile.models.Sale;
+import java.util.ArrayList;
+import java.util.List;
 
+import javax.inject.Inject;
+
+import dagger.hilt.android.AndroidEntryPoint;
+
+@AndroidEntryPoint
 public class SaleFragment extends Fragment implements SaleAdapter.OnSaleClickListener {
 
-    private List<SaleDTO> saleList = new ArrayList<>();
-    private List<SaleDTO> filteredList = new ArrayList<>();
+    private FragmentSaleBinding binding;
+    private List<Sale> saleList = new ArrayList<>();
+    private List<Sale> filteredList = new ArrayList<>();
     private SaleAdapter adapter;
-    private SwipeRefreshLayout swipeRefresh;
-    private EditText etSearch;
+
+    @Inject SaleApi api;
 
     @Override
-    public View onCreateView(LayoutInflater inflater, ViewGroup container,
+    public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
-        View view = inflater.inflate(R.layout.fragment_sale, container, false);
+        binding = FragmentSaleBinding.inflate(inflater, container, false);
 
-        setupRecyclerView(view);
-        setupSearch(view);
-        setupSwipeRefresh(view);
-        loadSales();
+        setupRecyclerView();
+        loadSaleData(); 
+        setupSearch();
+        setupSwipeRefresh();
 
-        FloatingActionButton fab = view.findViewById(R.id.fabAddSale);
-        fab.setOnClickListener(v -> openDetail(-1, null));
-
-        ImageButton hamburger = view.findViewById(R.id.btnHamburgerSale);
-        hamburger.setOnClickListener(v -> {
-            ListFragment lf = (ListFragment) getParentFragment();
-            if (lf != null) lf.openDrawer();
+        // Make the hamburger button open the drawer from listFragment
+        binding.btnHamburger.setOnClickListener(v -> {
+            Fragment parent = getParentFragment();
+            if (parent != null) {
+                Fragment grandParent = parent.getParentFragment();
+                if (grandParent instanceof ListFragment) {
+                    ((ListFragment) grandParent).openDrawer();
+                }
+            }
         });
 
-        // ← moved inside onCreateView
-        Button btnRefund = view.findViewById(R.id.btnOpenRefund);
-        btnRefund.setOnClickListener(v -> {
-            RefundFragment refundFragment = new RefundFragment();
-            ListFragment lf = (ListFragment) getParentFragment();
-            if (lf != null) lf.loadFragment(refundFragment);
-        });
-
-        return view;
+        return binding.getRoot();
     }
 
-    private void setupRecyclerView(View view) {
-        RecyclerView rv = view.findViewById(R.id.recyclerViewSales);
-        adapter = new SaleAdapter(filteredList, this);
-        rv.setLayoutManager(new LinearLayoutManager(getContext()));
-        rv.setAdapter(adapter);
+    @Override
+    public void onDestroyView() {
+        super.onDestroyView();
+        binding = null;
     }
 
-    private void setupSearch(View view) {
-        etSearch = view.findViewById(R.id.etSearchSale);
-        etSearch.addTextChangedListener(new TextWatcher() {
-            public void beforeTextChanged(CharSequence s, int a, int b, int c) {}
-            public void afterTextChanged(Editable s) {}
-            public void onTextChanged(CharSequence s, int a, int b, int c) {
-                filter(s.toString());
+    private void setupSearch() {
+        binding.etSearchSale.addTextChangedListener(new TextWatcher() {
+            @Override public void beforeTextChanged(CharSequence s, int start, int count, int after) {
+            }
+
+            @Override
+            public void onTextChanged(CharSequence s, int start, int before, int count) {
+                filterSales(s.toString());
+            }
+
+            @Override
+            public void afterTextChanged(Editable s) {
             }
         });
     }
 
-    private void setupSwipeRefresh(View view) {
-        swipeRefresh = view.findViewById(R.id.swipeRefreshSale);
-        swipeRefresh.setOnRefreshListener(this::loadSales);
-    }
-
-    private void filter(String query) {
+    private void filterSales(String query) {
         filteredList.clear();
         if (query.isEmpty()) {
             filteredList.addAll(saleList);
         } else {
             String lower = query.toLowerCase();
-            for (SaleDTO s : saleList) {
-                if ((s.getEmployeeName() != null && s.getEmployeeName().toLowerCase().contains(lower))
-                        || (s.getStoreName() != null && s.getStoreName().toLowerCase().contains(lower))
-                        || (s.getPaymentMethod() != null && s.getPaymentMethod().toLowerCase().contains(lower))) {
+            for (Sale s : saleList) {
+                if (s.getItemName().toLowerCase().contains(lower)
+                        || s.getEmployeeName().toLowerCase().contains(lower)
+                        || s.getSaleDate().toLowerCase().contains(lower)
+                        || s.getPaymentMethod().toLowerCase().contains(lower)
+                        || String.valueOf(s.getSaleId()).contains(lower)) {
                     filteredList.add(s);
                 }
             }
@@ -99,44 +99,47 @@ public class SaleFragment extends Fragment implements SaleAdapter.OnSaleClickLis
         adapter.notifyDataSetChanged();
     }
 
-    public void loadSales() {
-        if (swipeRefresh != null) swipeRefresh.setRefreshing(true);
-        RetrofitClient.getSaleApi(requireContext()).getAllSales(0, 100)
-                .enqueue(new Callback<PageResponse<SaleDTO>>() {
-                    public void onResponse(Call<PageResponse<SaleDTO>> c,
-                                           Response<PageResponse<SaleDTO>> r) {
-                        if (swipeRefresh != null) swipeRefresh.setRefreshing(false);
-                        if (r.isSuccessful() && r.body() != null) {
-                            saleList.clear();
-                            saleList.addAll(r.body().getContent());
-                            filter(etSearch != null ? etSearch.getText().toString() : "");
-                        } else {
-                            Toast.makeText(getContext(), "Failed to load sales",
-                                    Toast.LENGTH_SHORT).show();
-                        }
-                    }
-                    public void onFailure(Call<PageResponse<SaleDTO>> c, Throwable t) {
-                        if (swipeRefresh != null) swipeRefresh.setRefreshing(false);
-                        Log.e("SaleFragment", t.getMessage());
-                    }
-                });
-    }
-
-    public void openDetail(int position, SaleDTO sale) {
-        SaleDetailFragment detail = new SaleDetailFragment();
-        Bundle args = new Bundle();
-        if (position != -1 && sale != null) {
-            args.putLong("saleId", sale.getSaleId());
-            args.putBoolean("isRefund", Boolean.TRUE.equals(sale.getIsRefund()));
-            args.putBoolean("viewOnly", true);
-        }
-        detail.setArguments(args);
-        ListFragment lf = (ListFragment) getParentFragment();
-        if (lf != null) lf.loadFragment(detail);
+    private void setupSwipeRefresh() {
+        binding.swipeRefreshSale.setOnRefreshListener(() -> {
+            loadSaleData();
+            binding.swipeRefreshSale.setRefreshing(false);
+        });
     }
 
+    // When a sale row is clicked, open the refund screen for that sale
     @Override
     public void onSaleClick(int position) {
-        openDetail(position, filteredList.get(position));
+        Sale sale = filteredList.get(position);
+        Bundle args = new Bundle();
+        args.putInt("saleId", sale.getSaleId());
+        args.putString("saleDate", sale.getSaleDate());
+        args.putString("employeeName", sale.getEmployeeName());
+        args.putDouble("total", sale.getTotal());
+        args.putString("paymentMethod", sale.getPaymentMethod());
+        
+        NavHostFragment.findNavController(this).navigate(R.id.nav_refund_detail, args);
     }
-}
+
+    public void reloadSales() {
+        loadSaleData();
+    }
+
+    // TODO: Replace with actual API call - GET v1/sales
+    private void loadSaleData() {
+        saleList.clear();
+        saleList.add(new Sale(1, "2026-03-01", "John Smith", "Premium Dog Food", 2, 45.99, 91.98, "Card", false));
+        saleList.add(new Sale(2, "2026-03-02", "Jane Doe", "Cat Toy Bundle", 1, 19.99, 19.99, "Cash", false));
+        saleList.add(new Sale(3, "2026-03-03", "John Smith", "Pet Shampoo", 3, 12.99, 38.97, "Card", false));
+        saleList.add(new Sale(4, "2026-03-04", "Jane Doe", "Dog Bed - Large", 1, 89.99, 89.99, "Cash", true));
+        filteredList.clear();
+        filteredList.addAll(saleList);
+        if (adapter != null)
+            adapter.notifyDataSetChanged();
+    }
+
+    private void setupRecyclerView() {
+        adapter = new SaleAdapter(filteredList, this);
+        binding.recyclerViewSales.setLayoutManager(new LinearLayoutManager(getContext()));
+        binding.recyclerViewSales.setAdapter(adapter);
+    }
+}

android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/ServiceFragment.java

@@ -1,189 +1,241 @@
 package com.example.petstoremobile.fragments.listfragments;
 
 import android.os.Bundle;
-
-import androidx.fragment.app.Fragment;
-import androidx.recyclerview.widget.LinearLayoutManager;
-import androidx.recyclerview.widget.RecyclerView;
-import androidx.swiperefreshlayout.widget.SwipeRefreshLayout;
-
 import android.text.Editable;
 import android.text.TextWatcher;
 import android.util.Log;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
-import android.widget.EditText;
-import android.widget.ImageButton;
 import android.widget.Toast;
 
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.fragment.app.Fragment;
+import androidx.lifecycle.ViewModelProvider;
+import androidx.navigation.fragment.NavHostFragment;
+import androidx.recyclerview.widget.LinearLayoutManager;
+import androidx.recyclerview.widget.RecyclerView;
+
 import com.example.petstoremobile.R;
 import com.example.petstoremobile.adapters.ServiceAdapter;
-import com.example.petstoremobile.api.RetrofitClient;
-import com.example.petstoremobile.api.ServiceApi;
-import com.example.petstoremobile.dtos.PageResponse;
+import com.example.petstoremobile.databinding.FragmentServiceBinding;
 import com.example.petstoremobile.dtos.ServiceDTO;
 import com.example.petstoremobile.fragments.ListFragment;
-import com.example.petstoremobile.fragments.listfragments.detailfragments.ServiceDetailFragment;
-import com.google.android.material.floatingactionbutton.FloatingActionButton;
+import com.example.petstoremobile.utils.BulkDeleteHandler;
+import com.example.petstoremobile.utils.Resource;
+import com.example.petstoremobile.viewmodels.ServiceViewModel;
 
 import java.util.ArrayList;
 import java.util.List;
 
-import retrofit2.Call;
-import retrofit2.Callback;
-import retrofit2.Response;
+import dagger.hilt.android.AndroidEntryPoint;
 
+/**
+ * Fragment class for displaying a list of services in a RecyclerView.
+ */
+@AndroidEntryPoint
 public class ServiceFragment extends Fragment implements ServiceAdapter.OnServiceClickListener {
 
-    private List<ServiceDTO> serviceList = new ArrayList<>();
-    private List<ServiceDTO> filteredList = new ArrayList<>();
+    private static final String TAG = "ServiceFragment";
+    private static final int PAGE_SIZE = 20;
+
+    private FragmentServiceBinding binding;
+    private final List<ServiceDTO> serviceList = new ArrayList<>();
     private ServiceAdapter adapter;
-    private ImageButton hamburger;
-    private ServiceApi api;
-    private SwipeRefreshLayout swipeRefreshLayout;
-    private EditText etSearch;
+    private ServiceViewModel viewModel;
+    private BulkDeleteHandler bulkDeleteHandler;
 
-    //load service view
+    // Pagination
+    private int currentPage = 0;
+    private boolean isLastPage = false;
+    private boolean isLoading = false;
+
+    /**
+     * Initializes the fragment and its associated ViewModel.
+     */
     @Override
-    public View onCreateView(LayoutInflater inflater, ViewGroup container,
+    public void onCreate(@Nullable Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        viewModel = new ViewModelProvider(this).get(ServiceViewModel.class);
+    }
+
+    /**
+     * Sets up the fragment's UI components, including RecyclerView, search, and swipe-to-refresh.
+     */
+    @Override
+    public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
-        View view = inflater.inflate(R.layout.fragment_service, container, false);
+        binding = FragmentServiceBinding.inflate(inflater, container, false);
 
-        api = RetrofitClient.getServiceApi(requireContext());
-        hamburger = view.findViewById(R.id.btnHamburger);
+        setupRecyclerView();
+        setupSearch();
+        setupSwipeRefresh();
+        setupFilterToggle();
+        setupBulkDelete();
+        loadServices(true);
 
-        setupRecyclerView(view);
-        setupSearch(view);
-        setupSwipeRefresh(view);
-        loadServiceData();
+        binding.fabAddService.setOnClickListener(v -> openDetail(null));
 
-        //Add button to opens the add dialog
-        FloatingActionButton fabAddService = view.findViewById(R.id.fabAddService);
-        fabAddService.setOnClickListener(v -> openServiceDetails(-1));
-
-        //Make the hamburger button open the drawer from listFragment
-        hamburger.setOnClickListener(v -> {
-            ListFragment listFragment = (ListFragment) getParentFragment();
-            //if list fragment is found then use its helper function to open the drawer
-            if (listFragment != null) {
-                listFragment.openDrawer();
+        binding.btnHamburger.setOnClickListener(v -> {
+            Fragment parent = getParentFragment();
+            if (parent != null) {
+                Fragment grandParent = parent.getParentFragment();
+                if (grandParent instanceof ListFragment) {
+                    ((ListFragment) grandParent).openDrawer();
+                }
             }
         });
 
-        return view;
+        return binding.getRoot();
     }
 
-    private void setupSearch(View view) {
-        etSearch = view.findViewById(R.id.etSearchService);
-        etSearch.addTextChangedListener(new TextWatcher() {
+    private void setupBulkDelete() {
+        bulkDeleteHandler = new BulkDeleteHandler(
+                this,
+                binding.layoutBulkDelete,
+                binding.tvSelectionCount,
+                binding.btnBulkDelete,
+                adapter,
+                "service",
+                viewModel::bulkDeleteServices,
+                () -> loadServices(true)
+        );
+    }
+
+    @Override
+    public void onDestroyView() {
+        super.onDestroyView();
+        binding = null;
+    }
+
+    /**
+     * Sets up the filter toggle button to show/hide the filter layout.
+     */
+    private void setupFilterToggle() {
+        binding.btnToggleFilter.setOnClickListener(v -> {
+            if (binding.layoutFilter.getVisibility() == View.GONE) {
+                binding.layoutFilter.setVisibility(View.VISIBLE);
+                binding.btnToggleFilter.setImageResource(android.R.drawable.ic_menu_close_clear_cancel);
+            } else {
+                binding.layoutFilter.setVisibility(View.GONE);
+                binding.btnToggleFilter.setImageResource(android.R.drawable.ic_menu_search);
+
+                // Reset filters when closing
+                binding.etSearchService.setText("");
+            }
+        });
+    }
+
+    /**
+     * Sets up the search bar for filtering.
+     */
+    private void setupSearch() {
+        binding.etSearchService.addTextChangedListener(new TextWatcher() {
             @Override public void beforeTextChanged(CharSequence s, int start, int count, int after) {}
             @Override public void onTextChanged(CharSequence s, int start, int before, int count) {
-                filterServices(s.toString());
+                loadServices(true);
             }
             @Override public void afterTextChanged(Editable s) {}
         });
     }
 
-    private void filterServices(String query) {
-        filteredList.clear();
-        if (query.isEmpty()) {
-            filteredList.addAll(serviceList);
-        } else {
-            String lower = query.toLowerCase();
-            for (ServiceDTO s : serviceList) {
-                if (s.getServiceName().toLowerCase().contains(lower)
-                        || s.getServiceDesc().toLowerCase().contains(lower)) {
-                    filteredList.add(s);
+    /**
+     * Initializes the RecyclerView with a layout manager and adapter.
+     */
+    private void setupRecyclerView() {
+        adapter = new ServiceAdapter(serviceList, this);
+        binding.recyclerViewServices.setLayoutManager(new LinearLayoutManager(getContext()));
+        binding.recyclerViewServices.setAdapter(adapter);
+
+        binding.recyclerViewServices.addOnScrollListener(new RecyclerView.OnScrollListener() {
+            @Override
+            public void onScrolled(@NonNull RecyclerView recyclerView, int dx, int dy) {
+                if (dy <= 0) return;
+                LinearLayoutManager lm = (LinearLayoutManager) binding.recyclerViewServices.getLayoutManager();
+                if (lm == null) return;
+                int visible = lm.getChildCount();
+                int total = lm.getItemCount();
+                int firstVis = lm.findFirstVisibleItemPosition();
+                if (!isLoading && !isLastPage && (visible + firstVis) >= total - 3) {
+                    loadServices(false);
                 }
             }
-        }
-        adapter.notifyDataSetChanged();
-    }
-
-    private void setupSwipeRefresh(View view) {
-        swipeRefreshLayout = view.findViewById(R.id.swipeRefreshService);
-        swipeRefreshLayout.setOnRefreshListener(() -> {
-            loadServiceData();
         });
     }
 
-    //Open the service detail view depending on the mode
-    private void openServiceDetails(int position) {
-        ServiceDetailFragment detailFragment = new ServiceDetailFragment();
-
-        //Make a bundle to pass data to the detail fragment
-        Bundle args = new Bundle();
-        args.putInt("position", position);
-
-        //if editing a service, add the service data to the bundle
-        if (position != -1) {
-            ServiceDTO service = filteredList.get(position);
-            args.putInt("serviceId", service.getServiceId().intValue());
-            args.putString("serviceName", service.getServiceName());
-            args.putString("serviceDesc", service.getServiceDesc());
-            args.putInt("serviceDuration", service.getServiceDuration());
-            args.putDouble("servicePrice", service.getServicePrice());
-        }
-
-        //send the bundle to the detail fragment to display
-        detailFragment.setArguments(args);
-        //set the service fragment to the parent so we refer back to service view when save or delete is done
-        detailFragment.setServiceFragment(this);
-
-        //get ListFragment to load the the detail view
-        ListFragment listFragment = (ListFragment) getParentFragment();
-        if (listFragment != null) {
-            listFragment.loadFragment(detailFragment);
-        }
+    /**
+     * Sets up the SwipeRefreshLayout.
+     */
+    private void setupSwipeRefresh() {
+        binding.swipeRefreshService.setOnRefreshListener(() -> loadServices(true));
+    }
+
+    /**
+     * Fetches a page of services from the API.
+     */
+    private void loadServices(boolean reset) {
+        if (isLoading) return;
+
+        if (reset) {
+            currentPage = 0;
+            isLastPage = false;
+        }
+
+        String query = binding.etSearchService.getText().toString().trim();
+        if (query.isEmpty()) query = null;
+
+        viewModel.getAllServices(currentPage, PAGE_SIZE, query, "serviceName").observe(getViewLifecycleOwner(), resource -> {
+            if (resource == null) return;
+
+            switch (resource.status) {
+                case LOADING:
+                    isLoading = true;
+                    binding.swipeRefreshService.setRefreshing(true);
+                    break;
+                case SUCCESS:
+                    isLoading = false;
+                    binding.swipeRefreshService.setRefreshing(false);
+                    if (resource.data != null) {
+                        if (reset) serviceList.clear();
+                        serviceList.addAll(resource.data.getContent());
+                        adapter.notifyDataSetChanged();
+                        isLastPage = resource.data.isLast();
+                        if (!isLastPage) currentPage++;
+                    }
+                    break;
+                case ERROR:
+                    isLoading = false;
+                    binding.swipeRefreshService.setRefreshing(false);
+                    Log.e(TAG, "Error: " + resource.message);
+                    Toast.makeText(getContext(), "Failed to load services: " + resource.message, Toast.LENGTH_SHORT).show();
+                    break;
+            }
+        });
+    }
+
+    /**
+     * Navigates to the service detail screen.
+     */
+    private void openDetail(ServiceDTO service) {
+        Bundle args = new Bundle();
+        if (service != null) {
+            args.putLong("serviceId", service.getServiceId());
+        }
+        NavHostFragment.findNavController(this).navigate(R.id.nav_service_detail, args);
     }
 
-    // Called by ServiceAdapter when a row is clicked to open the details view
     @Override
     public void onServiceClick(int position) {
-        openServiceDetails(position);
-    }
-
-    // Helper function to get a list of all services from the backend
-    private void loadServiceData() {
-        if (swipeRefreshLayout != null) {
-            swipeRefreshLayout.setRefreshing(true);
+        if (position >= 0 && position < serviceList.size()) {
+            openDetail(serviceList.get(position));
         }
-        api.getAllServices(0, 100).enqueue(new Callback<PageResponse<ServiceDTO>>() {
-            @Override
-            public void onResponse(Call<PageResponse<ServiceDTO>> call, Response<PageResponse<ServiceDTO>> response) {
-                if (swipeRefreshLayout != null) {
-                    swipeRefreshLayout.setRefreshing(false);
-                }
-                if (response.isSuccessful() && response.body() != null) {
-                    serviceList.clear();
-                    serviceList.addAll(response.body().getContent());
-                    filterServices(etSearch.getText().toString());
-
-                } else {
-                    Log.e("onResponse: ", response.message());
-                }
-            }
-
-            @Override
-            public void onFailure(Call<PageResponse<ServiceDTO>> call, Throwable t) {
-                if (swipeRefreshLayout != null) {
-                    swipeRefreshLayout.setRefreshing(false);
-                }
-                if (getContext() != null) {
-                    Toast.makeText(getContext(),
-                            "Failed to load services", Toast.LENGTH_SHORT).show();
-                }
-                Log.e("onFailure: ", t.getMessage());
-            }
-        });
     }
 
-    //set up the recyclerview and adapter
-    private void setupRecyclerView(View view) {
-        RecyclerView recyclerView = view.findViewById(R.id.recyclerViewServices);
-        adapter = new ServiceAdapter(filteredList, this);
-        recyclerView.setLayoutManager(new LinearLayoutManager(getContext()));
-        recyclerView.setAdapter(adapter);
+    @Override
+    public void onSelectionChanged(int count) {
+        if (bulkDeleteHandler != null) {
+            bulkDeleteHandler.onSelectionChanged(count);
+        }
     }
-}
+}

android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/SupplierFragment.java

@@ -2,10 +2,12 @@ package com.example.petstoremobile.fragments.listfragments;
 
 import android.os.Bundle;
 
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 import androidx.fragment.app.Fragment;
+import androidx.lifecycle.ViewModelProvider;
+import androidx.navigation.fragment.NavHostFragment;
 import androidx.recyclerview.widget.LinearLayoutManager;
-import androidx.recyclerview.widget.RecyclerView;
-import androidx.swiperefreshlayout.widget.SwipeRefreshLayout;
 
 import android.text.Editable;
 import android.text.TextWatcher;
@@ -13,180 +15,205 @@ import android.util.Log;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
-import android.widget.EditText;
-import android.widget.ImageButton;
 import android.widget.Toast;
 
 import com.example.petstoremobile.R;
 import com.example.petstoremobile.adapters.SupplierAdapter;
-import com.example.petstoremobile.api.RetrofitClient;
-import com.example.petstoremobile.api.SupplierApi;
-import com.example.petstoremobile.dtos.PageResponse;
+import com.example.petstoremobile.databinding.FragmentSupplierBinding;
 import com.example.petstoremobile.dtos.SupplierDTO;
 import com.example.petstoremobile.fragments.ListFragment;
-import com.example.petstoremobile.fragments.listfragments.detailfragments.SupplierDetailFragment;
-import com.google.android.material.floatingactionbutton.FloatingActionButton;
+import com.example.petstoremobile.utils.BulkDeleteHandler;
+import com.example.petstoremobile.utils.Resource;
+import com.example.petstoremobile.viewmodels.SupplierViewModel;
 
 import java.util.ArrayList;
 import java.util.List;
 
-import retrofit2.Call;
-import retrofit2.Callback;
-import retrofit2.Response;
+import dagger.hilt.android.AndroidEntryPoint;
 
+@AndroidEntryPoint
 public class SupplierFragment extends Fragment implements SupplierAdapter.OnSupplierClickListener {
 
+    private FragmentSupplierBinding binding;
     private List<SupplierDTO> supplierList = new ArrayList<>();
-    private List<SupplierDTO> filteredList = new ArrayList<>();
     private SupplierAdapter adapter;
-    private ImageButton hamburger;
-    private SupplierApi api;
-    private SwipeRefreshLayout swipeRefreshLayout;
-    private EditText etSearch;
+    private SupplierViewModel viewModel;
+    private BulkDeleteHandler bulkDeleteHandler;
 
-    //load supplier view
+    /**
+     * Initializes the fragment and its associated SupplierViewModel.
+     */
     @Override
-    public View onCreateView(LayoutInflater inflater, ViewGroup container,
+    public void onCreate(@Nullable Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        viewModel = new ViewModelProvider(this).get(SupplierViewModel.class);
+    }
+
+    /**
+     * Sets up the fragment's UI components, including RecyclerView, search, and swipe-to-refresh.
+     */
+    @Override
+    public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
-        View view = inflater.inflate(R.layout.fragment_supplier, container, false);
+        binding = FragmentSupplierBinding.inflate(inflater, container, false);
 
-        api = RetrofitClient.getSupplierApi(requireContext());
-        hamburger = view.findViewById(R.id.btnHamburger);
-
-        setupRecyclerView(view);
-        setupSearch(view);
-        setupSwipeRefresh(view);
+        setupRecyclerView();
+        setupSearch();
+        setupSwipeRefresh();
+        setupFilterToggle();
+        setupBulkDelete();
         loadSupplierData();
 
         //Add button to opens the add dialog
-        FloatingActionButton fabAddSupplier = view.findViewById(R.id.fabAddSupplier);
-        fabAddSupplier.setOnClickListener(v -> openSupplierDetails(-1));
+        binding.fabAddSupplier.setOnClickListener(v -> openSupplierDetails(-1));
 
         //Make the hamburger button open the drawer from listFragment
-        hamburger.setOnClickListener(v -> {
-            ListFragment listFragment = (ListFragment) getParentFragment();
-            //if list fragment is found then use its helper function to open the drawer
-            if (listFragment != null) {
-                listFragment.openDrawer();
+        binding.btnHamburger.setOnClickListener(v -> {
+            Fragment parent = getParentFragment();
+            if (parent != null) {
+                Fragment grandParent = parent.getParentFragment();
+                if (grandParent instanceof ListFragment) {
+                    ((ListFragment) grandParent).openDrawer();
+                }
             }
         });
 
-        return view;
+        return binding.getRoot();
     }
 
-    private void setupSearch(View view) {
-        etSearch = view.findViewById(R.id.etSearchSupplier);
-        etSearch.addTextChangedListener(new TextWatcher() {
+    private void setupBulkDelete() {
+        bulkDeleteHandler = new BulkDeleteHandler(
+                this,
+                binding.layoutBulkDelete,
+                binding.tvSelectionCount,
+                binding.btnBulkDelete,
+                adapter,
+                "supplier",
+                viewModel::bulkDeleteSuppliers,
+                this::loadSupplierData
+        );
+    }
+
+    @Override
+    public void onDestroyView() {
+        super.onDestroyView();
+        binding = null;
+    }
+
+    /**
+     * Sets up the filter toggle button to show/hide the filter layout.
+     */
+    private void setupFilterToggle() {
+        binding.btnToggleFilter.setOnClickListener(v -> {
+            if (binding.layoutFilter.getVisibility() == View.GONE) {
+                binding.layoutFilter.setVisibility(View.VISIBLE);
+                binding.btnToggleFilter.setImageResource(android.R.drawable.ic_menu_close_clear_cancel);
+            } else {
+                binding.layoutFilter.setVisibility(View.GONE);
+                binding.btnToggleFilter.setImageResource(android.R.drawable.ic_menu_search);
+
+                // Reset search when closing
+                binding.etSearchSupplier.setText("");
+            }
+        });
+    }
+
+    /**
+     * Configures the search bar for filtering.
+     */
+    private void setupSearch() {
+        binding.etSearchSupplier.addTextChangedListener(new TextWatcher() {
             @Override public void beforeTextChanged(CharSequence s, int start, int count, int after) {}
             @Override public void onTextChanged(CharSequence s, int start, int before, int count) {
-                filterSuppliers(s.toString());
+                loadSupplierData();
             }
             @Override public void afterTextChanged(Editable s) {}
         });
     }
 
-    private void filterSuppliers(String query) {
-        filteredList.clear();
-        if (query.isEmpty()) {
-            filteredList.addAll(supplierList);
-        } else {
-            String lower = query.toLowerCase();
-            for (SupplierDTO s : supplierList) {
-                if (s.getSupCompany().toLowerCase().contains(lower)
-                        || s.getSupContactFirstName().toLowerCase().contains(lower)
-                        || s.getSupContactLastName().toLowerCase().contains(lower)) {
-                    filteredList.add(s);
-                }
-            }
-        }
-        adapter.notifyDataSetChanged();
+    /**
+     * Sets up the SwipeRefreshLayout to allow manual reloading of supplier data.
+     */
+    private void setupSwipeRefresh() {
+        binding.swipeRefreshSupplier.setOnRefreshListener(this::loadSupplierData);
     }
 
-    private void setupSwipeRefresh(View view) {
-        swipeRefreshLayout = view.findViewById(R.id.swipeRefreshSupplier);
-        swipeRefreshLayout.setOnRefreshListener(() -> {
-            loadSupplierData();
-        });
-    }
-
-    //Open the supplier detail view depending on the mode
+    /**
+     * Navigates to the supplier detail screen for editing an existing record or adding a new one.
+     */
     private void openSupplierDetails(int position) {
-        SupplierDetailFragment detailFragment = new SupplierDetailFragment();
-
         //Make a bundle to pass data to the detail fragment
         Bundle args = new Bundle();
-        args.putInt("position", position);
 
-        //if editing a supplier, add the supplier data to the bundle
+        //if editing a supplier, add the supplier id to the bundle
         if (position != -1) {
-            SupplierDTO supplier = filteredList.get(position);
-            args.putInt("supId", supplier.getSupId().intValue());
-            args.putString("supCompany", supplier.getSupCompany());
-            args.putString("supContactFirstName", supplier.getSupContactFirstName());
-            args.putString("supContactLastName", supplier.getSupContactLastName());
-            args.putString("supEmail", supplier.getSupEmail());
-            args.putString("supPhone", supplier.getSupPhone());
+            SupplierDTO supplier = supplierList.get(position);
+            args.putLong("supId", supplier.getSupId());
         }
 
-        //send the bundle to the detail fragment to display
-        detailFragment.setArguments(args);
-        //set the supplier fragment to the parent so we refer back to supplier view when save or delete is done
-        detailFragment.setSupplierFragment(this);
-
-        //get ListFragment to load the the detail view
-        ListFragment listFragment = (ListFragment) getParentFragment();
-        if (listFragment != null) {
-            listFragment.loadFragment(detailFragment);
-        }
+        NavHostFragment.findNavController(this).navigate(R.id.nav_supplier_detail, args);
     }
 
 
-    // Called by SupplierAdapter when a row is clicked to open the details view
+    /**
+     * Handles item click in the supplier list.
+     */
     @Override
     public void onSupplierClick(int position) {
         openSupplierDetails(position);
     }
 
-    // Helper function to get a list of all suppliers from the backend
-    private void loadSupplierData() {
-        if (swipeRefreshLayout != null) {
-            swipeRefreshLayout.setRefreshing(true);
+    @Override
+    public void onSelectionChanged(int count) {
+        if (bulkDeleteHandler != null) {
+            bulkDeleteHandler.onSelectionChanged(count);
         }
-        api.getAllSuppliers(0, 100).enqueue(new Callback<PageResponse<SupplierDTO>>() {
-            @Override
-            public void onResponse(Call<PageResponse<SupplierDTO>> call, Response<PageResponse<SupplierDTO>> response) {
-                if (swipeRefreshLayout != null) {
-                    swipeRefreshLayout.setRefreshing(false);
-                }
-                if (response.isSuccessful() && response.body() != null) {
-                    supplierList.clear();
-                    supplierList.addAll(response.body().getContent());
-                    filterSuppliers(etSearch.getText().toString());
+    }
 
-                } else {
-                    Log.e("onResponse: ", response.message());
-                }
-            }
+    /**
+     * Fetches all supplier data from the server through the ViewModel and updates the UI.
+     */
+    private void loadSupplierData() {
+        String query = binding.etSearchSupplier != null ? binding.etSearchSupplier.getText().toString().trim() : "";
+        if (query.isEmpty()) query = null;
 
-            @Override
-            public void onFailure(Call<PageResponse<SupplierDTO>> call, Throwable t) {
-                if (swipeRefreshLayout != null) {
-                    swipeRefreshLayout.setRefreshing(false);
-                }
-                if (getContext() != null) {
-                    Toast.makeText(getContext(),
-                            "Failed to load suppliers", Toast.LENGTH_SHORT).show();
-                }
-                Log.e("onFailure: ", t.getMessage());
+        //Load suppliers from the backend with query and default sort
+        viewModel.getAllSuppliers(0, 100, query, "supCompany").observe(getViewLifecycleOwner(), resource -> {
+            if (resource == null) return;
+
+            // Check the status to see if the resource is loaded and display the data
+            switch (resource.status) {
+                case LOADING:
+                    // Show loading indicator
+                    binding.swipeRefreshSupplier.setRefreshing(true);
+                    break;
+                case SUCCESS:
+                    // Hide loading indicator and display data
+                    binding.swipeRefreshSupplier.setRefreshing(false);
+                    if (resource.data != null) {
+                        supplierList.clear();
+                        supplierList.addAll(resource.data.getContent());
+                        adapter.notifyDataSetChanged();
+                    }
+                    break;
+                case ERROR:
+                    // Hide loading indicator and toast error message
+                    binding.swipeRefreshSupplier.setRefreshing(false);
+                    if (getContext() != null) {
+                        Toast.makeText(getContext(), "Failed to load suppliers: " + resource.message, Toast.LENGTH_SHORT).show();
+                    }
+                    Log.e("SupplierFragment", "Error loading suppliers: " + resource.message);
+                    break;
             }
         });
     }
 
-    //set up the recyclerview and adapter
-    private void setupRecyclerView(View view) {
-        RecyclerView recyclerView = view.findViewById(R.id.recyclerViewSuppliers);
-        adapter = new SupplierAdapter(filteredList, this);
-        recyclerView.setLayoutManager(new LinearLayoutManager(getContext()));
-        recyclerView.setAdapter(adapter);
+    /**
+     * Initializes the RecyclerView with a layout manager and adapter for displaying suppliers.
+     */
+    private void setupRecyclerView() {
+        adapter = new SupplierAdapter(supplierList, this);
+        binding.recyclerViewSuppliers.setLayoutManager(new LinearLayoutManager(getContext()));
+        binding.recyclerViewSuppliers.setAdapter(adapter);
     }
-}
+}

android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/AdoptionDetailFragment.java

@@ -2,78 +2,109 @@ package com.example.petstoremobile.fragments.listfragments.detailfragments;
 
 import android.app.DatePickerDialog;
 import android.os.Bundle;
-import android.util.Log;
 import android.view.*;
 import android.widget.*;
 import androidx.annotation.NonNull;
-import androidx.appcompat.app.AlertDialog;
+import androidx.annotation.Nullable;
 import androidx.fragment.app.Fragment;
-import com.example.petstoremobile.R;
-import com.example.petstoremobile.api.*;
-import com.example.petstoremobile.dtos.*;
-import com.example.petstoremobile.fragments.ListFragment;
-import java.util.*;
-import retrofit2.*;
+import androidx.lifecycle.ViewModelProvider;
+import androidx.navigation.fragment.NavHostFragment;
 
+import com.example.petstoremobile.databinding.FragmentAdoptionDetailBinding;
+import com.example.petstoremobile.dtos.*;
+import com.example.petstoremobile.utils.DialogUtils;
+import com.example.petstoremobile.utils.Resource;
+import com.example.petstoremobile.utils.SpinnerUtils;
+import com.example.petstoremobile.viewmodels.AdoptionViewModel;
+import com.example.petstoremobile.viewmodels.CustomerViewModel;
+import com.example.petstoremobile.viewmodels.PetViewModel;
+import com.example.petstoremobile.viewmodels.StoreViewModel;
+import com.example.petstoremobile.viewmodels.UserViewModel;
+
+import java.math.BigDecimal;
+import java.util.*;
+
+import dagger.hilt.android.AndroidEntryPoint;
+
+/**
+ * Fragment for displaying and editing adoption request details.
+ */
+@AndroidEntryPoint
 public class AdoptionDetailFragment extends Fragment {
 
-    private TextView tvMode, tvAdoptionId;
-    private EditText etAdoptionDate;
-    private Spinner spinnerPet, spinnerCustomer, spinnerEmployee, spinnerStatus;
-    private Button btnSave, btnDelete, btnBack;
+    private FragmentAdoptionDetailBinding binding;
 
     private long adoptionId = -1;
     private boolean isEditing = false;
     private long preselectedPetId = -1;
     private long preselectedCustomerId = -1;
-
-    private List<EmployeeDTO> employeeList = new ArrayList<>();
+    private long preselectedStoreId = -1;
     private long preselectedEmployeeId = -1;
 
     private List<PetDTO> petList = new ArrayList<>();
     private List<CustomerDTO> customerList = new ArrayList<>();
+    private List<StoreDTO> storeList = new ArrayList<>();
+    private List<UserDTO> employeeList = new ArrayList<>();
 
-    private final String[] STATUSES = {"Pending", "Approved", "Rejected"};
+    private final String[] STATUSES = {"Pending", "Completed", "Cancelled"};
+
+    private AdoptionViewModel adoptionViewModel;
+    private PetViewModel petViewModel;
+    private CustomerViewModel customerViewModel;
+    private StoreViewModel storeViewModel;
+    private UserViewModel userViewModel;
+
+    @Override
+    public void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        adoptionViewModel = new ViewModelProvider(this).get(AdoptionViewModel.class);
+        petViewModel = new ViewModelProvider(this).get(PetViewModel.class);
+        customerViewModel = new ViewModelProvider(this).get(CustomerViewModel.class);
+        storeViewModel = new ViewModelProvider(this).get(StoreViewModel.class);
+        userViewModel = new ViewModelProvider(this).get(UserViewModel.class);
+    }
 
     @Override
     public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
-        View view = inflater.inflate(R.layout.fragment_adoption_detail, container, false);
-        initViews(view);
+        binding = FragmentAdoptionDetailBinding.inflate(inflater, container, false);
+        return binding.getRoot();
+    }
+
+    @Override
+    public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
+        super.onViewCreated(view, savedInstanceState);
         setupSpinners();
         setupDatePicker();
-        loadData();
+        loadSpinnersData();
         handleArguments();
 
-        btnBack.setOnClickListener(v -> navigateBack());
-        btnSave.setOnClickListener(v -> saveAdoption());
-        btnDelete.setOnClickListener(v -> confirmDelete());
-        return view;
+        binding.btnAdoptionBack.setOnClickListener(v -> navigateBack());
+        binding.btnSaveAdoption.setOnClickListener(v -> saveAdoption());
+        binding.btnDeleteAdoption.setOnClickListener(v -> confirmDelete());
     }
 
-    private void initViews(View v) {
-        tvMode         = v.findViewById(R.id.tvAdoptionMode);
-        tvAdoptionId   = v.findViewById(R.id.tvAdoptionId);
-        etAdoptionDate = v.findViewById(R.id.etAdoptionDate);
-        spinnerPet     = v.findViewById(R.id.spinnerAdoptionPet);
-        spinnerCustomer= v.findViewById(R.id.spinnerAdoptionCustomer);
-        spinnerEmployee = v.findViewById(R.id.spinnerAdoptionEmployee);
-        spinnerStatus  = v.findViewById(R.id.spinnerAdoptionStatus);
-        btnSave        = v.findViewById(R.id.btnSaveAdoption);
-        btnDelete      = v.findViewById(R.id.btnDeleteAdoption);
-        btnBack        = v.findViewById(R.id.btnAdoptionBack);
+    @Override
+    public void onDestroyView() {
+        super.onDestroyView();
+        binding = null;
     }
 
+    /**
+     * Configures the spinner for adoption status.
+     */
     private void setupSpinners() {
-        spinnerStatus.setAdapter(new ArrayAdapter<>(requireContext(),
-                android.R.layout.simple_spinner_item, STATUSES));
+        SpinnerUtils.setupStringSpinner(requireContext(), binding.spinnerAdoptionStatus, STATUSES);
     }
 
+    /**
+     * Configures the date picker dialog for the adoption date field.
+     */
     private void setupDatePicker() {
-        etAdoptionDate.setOnClickListener(v -> {
+        binding.etAdoptionDate.setOnClickListener(v -> {
             Calendar c = Calendar.getInstance();
             new DatePickerDialog(requireContext(),
-                    (dp, y, m, d) -> etAdoptionDate.setText(
+                    (dp, y, m, d) -> binding.etAdoptionDate.setText(
                             String.format("%04d-%02d-%02d", y, m + 1, d)),
                     c.get(Calendar.YEAR),
                     c.get(Calendar.MONTH),
@@ -81,217 +112,238 @@ public class AdoptionDetailFragment extends Fragment {
         });
     }
 
-    private void loadData() {
+    /**
+     * Fetches required data for spinners from the backend.
+     */
+    private void loadSpinnersData() {
         loadPets();
         loadCustomers();
+        loadStores();
         loadEmployees();
     }
 
+    /**
+     * Loads the list of pets from the API.
+     */
     private void loadPets() {
-        RetrofitClient.getPetApi(requireContext()).getAllPets(0, 200)
-                .enqueue(new Callback<PageResponse<PetDTO>>() {
-                    public void onResponse(Call<PageResponse<PetDTO>> c,
-                                           Response<PageResponse<PetDTO>> r) {
-                        if (r.isSuccessful() && r.body() != null) {
-                            petList = r.body().getContent();
-                            populatePetSpinner();
-                        }
-                    }
-                    public void onFailure(Call<PageResponse<PetDTO>> c, Throwable t) {
-                        Log.e("ADOPTION", "Pet load failed: " + t.getMessage());
-                    }
-                });
-    }
-
-    private void populatePetSpinner() {
-        List<String> names = new ArrayList<>();
-        names.add("-- Select Pet --");
-        for (PetDTO p : petList) names.add(p.getPetName());
-        spinnerPet.setAdapter(new ArrayAdapter<>(requireContext(),
-                android.R.layout.simple_spinner_item, names));
-        if (preselectedPetId != -1) {
-            for (int i = 0; i < petList.size(); i++) {
-                if (petList.get(i).getPetId().equals(preselectedPetId)) {
-                    spinnerPet.setSelection(i + 1); break;
-                }
+        petViewModel.getAllPets(0, 200, null, null, null, null, "petName").observe(getViewLifecycleOwner(), resource -> {
+            if (resource.status == Resource.Status.SUCCESS && resource.data != null) {
+                petList = resource.data.getContent();
+                refreshPetSpinner();
             }
-        }
+        });
     }
 
+    /**
+     * Populates the pet selection spinner with data.
+     */
+    private void refreshPetSpinner() {
+        SpinnerUtils.populateSpinner(requireContext(), binding.spinnerAdoptionPet, petList,
+                PetDTO::getPetName, "-- Select Pet --",
+                preselectedPetId, PetDTO::getPetId);
+    }
+
+    /**
+     * Loads the list of customers from the API.
+     */
     private void loadCustomers() {
-        RetrofitClient.getCustomerApi(requireContext()).getAllCustomers(0, 200)
-                .enqueue(new Callback<PageResponse<CustomerDTO>>() {
-                    public void onResponse(Call<PageResponse<CustomerDTO>> c,
-                                           Response<PageResponse<CustomerDTO>> r) {
-                        if (r.isSuccessful() && r.body() != null) {
-                            customerList = r.body().getContent();
-                            populateCustomerSpinner();
-                        }
-                    }
-                    public void onFailure(Call<PageResponse<CustomerDTO>> c, Throwable t) {
-                        Log.e("ADOPTION", "Customer load failed: " + t.getMessage());
-                    }
-                });
-    }
-
-    private void populateCustomerSpinner() {
-        List<String> names = new ArrayList<>();
-        names.add("-- Select Customer --");
-        for (CustomerDTO c : customerList)
-            names.add(c.getFirstName() + " " + c.getLastName());
-        spinnerCustomer.setAdapter(new ArrayAdapter<>(requireContext(),
-                android.R.layout.simple_spinner_item, names));
-        if (preselectedCustomerId != -1) {
-            for (int i = 0; i < customerList.size(); i++) {
-                if (customerList.get(i).getCustomerId().equals(preselectedCustomerId)) {
-                    spinnerCustomer.setSelection(i + 1); break;
-                }
+        customerViewModel.getAllCustomers(0, 200).observe(getViewLifecycleOwner(), resource -> {
+            if (resource.status == Resource.Status.SUCCESS && resource.data != null) {
+                customerList = resource.data.getContent();
+                refreshCustomerSpinner();
             }
-        }
+        });
     }
 
+    /**
+     * Populates the customer selection spinner with data.
+     */
+    private void refreshCustomerSpinner() {
+        SpinnerUtils.populateSpinner(requireContext(), binding.spinnerAdoptionCustomer, customerList,
+                item -> item.getFirstName() + " " + item.getLastName(),
+                "-- Select Customer --",
+                preselectedCustomerId, CustomerDTO::getCustomerId);
+    }
+
+    /**
+     * Loads the list of stores from the API.
+     */
+    private void loadStores() {
+        storeViewModel.getAllStores(0, 200).observe(getViewLifecycleOwner(), resource -> {
+            if (resource.status == Resource.Status.SUCCESS && resource.data != null) {
+                storeList = resource.data.getContent();
+                refreshStoreSpinner();
+            }
+        });
+    }
+
+    /**
+     * Populates the store selection spinner with data.
+     */
+    private void refreshStoreSpinner() {
+        SpinnerUtils.populateSpinner(requireContext(), binding.spinnerAdoptionStore, storeList,
+                StoreDTO::getStoreName, "-- Select Store --",
+                preselectedStoreId, StoreDTO::getStoreId);
+    }
+
+    /**
+     * Loads the list of employees from the API.
+     */
     private void loadEmployees() {
-        RetrofitClient.getEmployeeApi(requireContext()).getAllEmployees(0, 100)
-                .enqueue(new Callback<PageResponse<EmployeeDTO>>() {
-                    public void onResponse(Call<PageResponse<EmployeeDTO>> c,
-                                           Response<PageResponse<EmployeeDTO>> r) {
-                        if (r.isSuccessful() && r.body() != null) {
-                            employeeList = r.body().getContent();
-                            List<String> names = new ArrayList<>();
-                            names.add("-- Select Employee --");
-                            for (EmployeeDTO e : employeeList)
-                                names.add(e.getFullName() + " (" + e.getRole() + ")");
-                            spinnerEmployee.setAdapter(new ArrayAdapter<>(requireContext(),
-                                    android.R.layout.simple_spinner_item, names));
-                            if (preselectedEmployeeId != -1) {
-                                for (int i = 0; i < employeeList.size(); i++) {
-                                    if (employeeList.get(i).getEmployeeId() == preselectedEmployeeId) {
-                                        spinnerEmployee.setSelection(i + 1); break;
-                                    }
-                                }
-                            }
-                        }
-                    }
-                    public void onFailure(Call<PageResponse<EmployeeDTO>> c, Throwable t) {
-                        Log.e("ADOPTION", "Employee load failed: " + t.getMessage());
-                    }
-                });
+        userViewModel.getUsers("STAFF", 0, 100).observe(getViewLifecycleOwner(), resource -> {
+            if (resource.status == Resource.Status.SUCCESS && resource.data != null) {
+                employeeList = resource.data.getContent();
+                refreshEmployeeSpinner();
+            }
+        });
     }
 
+    /**
+     * Populates the employee selection spinner with data.
+     */
+    private void refreshEmployeeSpinner() {
+        SpinnerUtils.populateSpinner(requireContext(), binding.spinnerAdoptionEmployee, employeeList,
+                UserDTO::getFullName, "-- Select Staff --",
+                preselectedEmployeeId, UserDTO::getId);
+    }
+
+    /**
+     * Handles arguments to determine if the fragment is in edit or add mode.
+     */
     private void handleArguments() {
         Bundle a = getArguments();
         if (a != null && a.containsKey("adoptionId")) {
             isEditing = true;
-            adoptionId          = a.getLong("adoptionId");
-            preselectedPetId    = a.getLong("petId", -1);
-            preselectedCustomerId = a.getLong("customerId", -1);
-            preselectedEmployeeId = a.getLong("employeeId", -1);
-            tvMode.setText("Edit Adoption");
-            tvAdoptionId.setText("ID: " + adoptionId);
-            tvAdoptionId.setVisibility(View.VISIBLE);
-            etAdoptionDate.setText(a.getString("adoptionDate"));
-            btnDelete.setVisibility(View.VISIBLE);
-
-            // Pre-fill status
-            String status = a.getString("adoptionStatus", "Pending");
-            for (int i = 0; i < STATUSES.length; i++) {
-                if (STATUSES[i].equals(status)) {
-                    spinnerStatus.setSelection(i); break;
-                }
-            }
+            adoptionId = a.getLong("adoptionId");
+            binding.tvAdoptionMode.setText("Edit Adoption");
+            binding.tvAdoptionId.setText("ID: " + adoptionId);
+            binding.tvAdoptionId.setVisibility(View.VISIBLE);
+            binding.btnDeleteAdoption.setVisibility(View.VISIBLE);
+            loadAdoptionData();
         } else {
-            tvMode.setText("Add Adoption");
-            btnDelete.setVisibility(View.GONE);
-            tvAdoptionId.setVisibility(View.GONE);
+            binding.tvAdoptionMode.setText("Add Adoption");
+            binding.btnDeleteAdoption.setVisibility(View.GONE);
+            binding.tvAdoptionId.setVisibility(View.GONE);
         }
     }
 
+    /**
+     * Fetches specific adoption details from the backend using the ID.
+     */
+    private void loadAdoptionData() {
+        adoptionViewModel.getAdoptionById(adoptionId).observe(getViewLifecycleOwner(), resource -> {
+            if (resource == null) return;
+            if (resource.status == Resource.Status.SUCCESS && resource.data != null) {
+                AdoptionDTO a = resource.data;
+                preselectedPetId = a.getPetId() != null ? a.getPetId() : -1;
+                preselectedCustomerId = a.getCustomerId() != null ? a.getCustomerId() : -1;
+                preselectedStoreId = a.getSourceStoreId() != null ? a.getSourceStoreId() : -1;
+                preselectedEmployeeId = a.getEmployeeId() != null ? a.getEmployeeId() : -1;
+                
+                binding.etAdoptionDate.setText(a.getAdoptionDate());
+                binding.etAdoptionFee.setText(a.getAdoptionFee() != null ? a.getAdoptionFee().toString() : "");
+                SpinnerUtils.setSelectionByValue(binding.spinnerAdoptionStatus, a.getAdoptionStatus());
+                
+                refreshPetSpinner();
+                refreshCustomerSpinner();
+                refreshStoreSpinner();
+                refreshEmployeeSpinner();
+            } else if (resource.status == Resource.Status.ERROR) {
+                Toast.makeText(getContext(), "Failed to load adoption: " + resource.message, Toast.LENGTH_SHORT).show();
+            }
+        });
+    }
+
+    /**
+     * Validates input and saves the adoption request to the backend.
+     */
     private void saveAdoption() {
-        if (spinnerCustomer.getSelectedItemPosition() == 0) {
+        if (binding.spinnerAdoptionCustomer.getSelectedItemPosition() == 0) {
             Toast.makeText(getContext(), "Select a customer", Toast.LENGTH_SHORT).show(); return;
         }
-        if (spinnerPet.getSelectedItemPosition() == 0) {
+        if (binding.spinnerAdoptionPet.getSelectedItemPosition() == 0) {
             Toast.makeText(getContext(), "Select a pet", Toast.LENGTH_SHORT).show(); return;
         }
-        Long employeeId = null;
-        if (spinnerEmployee.getSelectedItemPosition() > 0) {
-            employeeId = employeeList
-                    .get(spinnerEmployee.getSelectedItemPosition() - 1)
-                    .getEmployeeId();
+        if (binding.spinnerAdoptionStore.getSelectedItemPosition() == 0) {
+            Toast.makeText(getContext(), "Select a store", Toast.LENGTH_SHORT).show(); return;
         }
-        String date = etAdoptionDate.getText().toString().trim();
+        String date = binding.etAdoptionDate.getText().toString().trim();
         if (date.isEmpty()) {
             Toast.makeText(getContext(), "Select a date", Toast.LENGTH_SHORT).show(); return;
         }
 
-        CustomerDTO customer = customerList.get(spinnerCustomer.getSelectedItemPosition() - 1);
-        PetDTO pet           = petList.get(spinnerPet.getSelectedItemPosition() - 1);
-        String status        = STATUSES[spinnerStatus.getSelectedItemPosition()];
+        BigDecimal fee = BigDecimal.ZERO;
+        String feeStr = binding.etAdoptionFee.getText().toString().trim();
+        if (!feeStr.isEmpty()) {
+            try {
+                fee = new BigDecimal(feeStr);
+            } catch (NumberFormatException e) {
+                Toast.makeText(getContext(), "Invalid fee format", Toast.LENGTH_SHORT).show();
+                return;
+            }
+        }
+
+        CustomerDTO customer = customerList.get(binding.spinnerAdoptionCustomer.getSelectedItemPosition() - 1);
+        PetDTO pet           = petList.get(binding.spinnerAdoptionPet.getSelectedItemPosition() - 1);
+        StoreDTO store       = storeList.get(binding.spinnerAdoptionStore.getSelectedItemPosition() - 1);
+        
+        Long employeeId = null;
+        if (binding.spinnerAdoptionEmployee.getSelectedItemPosition() > 0) {
+            employeeId = employeeList.get(binding.spinnerAdoptionEmployee.getSelectedItemPosition() - 1).getId();
+        }
+        
+        String status        = STATUSES[binding.spinnerAdoptionStatus.getSelectedItemPosition()];
 
         AdoptionDTO dto = new AdoptionDTO(
                 pet.getPetId(),
                 customer.getCustomerId(),
+                employeeId,
+                store.getStoreId(),
                 date,
                 status,
-                employeeId
+                fee
         );
 
-        Log.d("ADOPTION_SAVE", "petId=" + pet.getPetId()
-                + " customerId=" + customer.getCustomerId()
-                + " date=" + date + " status=" + status);
-
-        AdoptionApi api = RetrofitClient.getAdoptionApi(requireContext());
         if (isEditing) {
-            api.updateAdoption(adoptionId, dto).enqueue(simpleCallback("Updated"));
+            adoptionViewModel.updateAdoption(adoptionId, dto).observe(getViewLifecycleOwner(), resource -> {
+                if (resource.status == Resource.Status.SUCCESS) {
+                    Toast.makeText(getContext(), "Updated", Toast.LENGTH_SHORT).show();
+                    navigateBack();
+                } else if (resource.status == Resource.Status.ERROR) {
+                    Toast.makeText(getContext(), "Error: " + resource.message, Toast.LENGTH_SHORT).show();
+                }
+            });
         } else {
-            api.createAdoption(dto).enqueue(simpleCallback("Saved"));
+            adoptionViewModel.createAdoption(dto).observe(getViewLifecycleOwner(), resource -> {
+                if (resource.status == Resource.Status.SUCCESS) {
+                    Toast.makeText(getContext(), "Saved", Toast.LENGTH_SHORT).show();
+                    navigateBack();
+                } else if (resource.status == Resource.Status.ERROR) {
+                    Toast.makeText(getContext(), "Error: " + resource.message, Toast.LENGTH_SHORT).show();
+                }
+            });
         }
     }
 
-    private Callback<AdoptionDTO> simpleCallback(String msg) {
-        return new Callback<>() {
-            public void onResponse(Call<AdoptionDTO> c, Response<AdoptionDTO> r) {
-                Log.d("ADOPTION_SAVE", "Response: " + r.code());
-                if (r.isSuccessful()) {
-                    Toast.makeText(getContext(), msg, Toast.LENGTH_SHORT).show();
-                    navigateBack();
-                } else {
-                    try {
-                        String err = r.errorBody().string();
-                        Log.e("ADOPTION_SAVE", "Error: " + err);
-                        Toast.makeText(getContext(), "Error " + r.code(), Toast.LENGTH_SHORT).show();
-                    } catch (Exception e) {
-                        Log.e("ADOPTION_SAVE", "Failed to read error");
-                    }
-                }
-            }
-            public void onFailure(Call<AdoptionDTO> c, Throwable t) {
-                Log.e("ADOPTION_SAVE", "Failure: " + t.getMessage());
-                Toast.makeText(getContext(), "Network error", Toast.LENGTH_SHORT).show();
-            }
-        };
-    }
-
+    /**
+     * Shows a confirmation dialog before deleting an adoption request.
+     */
     private void confirmDelete() {
-        new AlertDialog.Builder(requireContext())
-                .setTitle("Delete Adoption?")
-                .setPositiveButton("Yes", (d, w) ->
-                        RetrofitClient.getAdoptionApi(requireContext())
-                                .deleteAdoption(adoptionId)
-                                .enqueue(new Callback<Void>() {
-                                    public void onResponse(Call<Void> c, Response<Void> r) {
-                                        navigateBack();
-                                    }
-                                    public void onFailure(Call<Void> c, Throwable t) {
-                                        Toast.makeText(getContext(), "Delete failed",
-                                                Toast.LENGTH_SHORT).show();
-                                    }
-                                }))
-                .setNegativeButton("No", null).show();
+        DialogUtils.showDeleteConfirmDialog(requireContext(), "Adoption", () ->
+                adoptionViewModel.deleteAdoption(adoptionId).observe(getViewLifecycleOwner(), resource -> {
+                    if (resource.status == Resource.Status.SUCCESS) {
+                        Toast.makeText(getContext(), "Deleted", Toast.LENGTH_SHORT).show();
+                        navigateBack();
+                    } else if (resource.status == Resource.Status.ERROR) {
+                        Toast.makeText(getContext(), "Delete failed: " + resource.message, Toast.LENGTH_SHORT).show();
+                    }
+                }));
     }
 
+    /**
+     * Navigates back to the previous fragment.
+     */
     private void navigateBack() {
-        ListFragment lf = (ListFragment) getParentFragment();
-        if (lf != null) lf.getChildFragmentManager().popBackStack();
+        NavHostFragment.findNavController(this).popBackStack();
     }
-}
+}

android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/AppointmentDetailFragment.java

@@ -6,22 +6,34 @@ import android.util.Log;
 import android.view.*;
 import android.widget.*;
 import androidx.annotation.NonNull;
-import androidx.appcompat.app.AlertDialog;
+import androidx.annotation.Nullable;
 import androidx.fragment.app.Fragment;
-import com.example.petstoremobile.R;
-import com.example.petstoremobile.api.*;
-import com.example.petstoremobile.dtos.*;
-import com.example.petstoremobile.fragments.ListFragment;
-import java.util.*;
-import retrofit2.*;
+import androidx.lifecycle.ViewModelProvider;
+import androidx.navigation.fragment.NavHostFragment;
 
+import com.example.petstoremobile.databinding.FragmentAppointmentDetailBinding;
+import com.example.petstoremobile.dtos.*;
+import com.example.petstoremobile.utils.DialogUtils;
+import com.example.petstoremobile.utils.Resource;
+import com.example.petstoremobile.utils.SpinnerUtils;
+import com.example.petstoremobile.viewmodels.AppointmentViewModel;
+import com.example.petstoremobile.viewmodels.CustomerViewModel;
+import com.example.petstoremobile.viewmodels.PetViewModel;
+import com.example.petstoremobile.viewmodels.ServiceViewModel;
+import com.example.petstoremobile.viewmodels.StoreViewModel;
+import com.example.petstoremobile.viewmodels.UserViewModel;
+
+import java.util.*;
+
+import dagger.hilt.android.AndroidEntryPoint;
+
+/**
+ * Fragment for displaying and editing appointment details.
+ */
+@AndroidEntryPoint
 public class AppointmentDetailFragment extends Fragment {
 
-    private TextView tvMode, tvAppointmentId;
-    private EditText etAppointmentDate;
-    private Spinner spinnerPet, spinnerService, spinnerStatus, spinnerHour, spinnerMinute;
-    private Spinner spinnerCustomer, spinnerStore;
-    private Button btnSave, btnDelete, btnBack;
+    private FragmentAppointmentDetailBinding binding;
 
     private long appointmentId = -1;
     private boolean isEditing = false;
@@ -29,66 +41,82 @@ public class AppointmentDetailFragment extends Fragment {
     private long preselectedServiceId = -1;
     private long preselectedCustomerId = -1;
     private long preselectedStoreId = -1;
+    private long preselectedStaffId = -1;
 
     private List<PetDTO> petList = new ArrayList<>();
     private List<ServiceDTO> serviceList = new ArrayList<>();
     private List<CustomerDTO> customerList = new ArrayList<>();
     private List<StoreDTO> storeList = new ArrayList<>();
-    private List<AppointmentDTO> allAppointments = new ArrayList<>();
+    private List<UserDTO> staffList = new ArrayList<>();
 
     private final Integer[] HOURS = {9,10,11,12,13,14,15,16,17};
     private final Integer[] MINUTES = {0,15,30,45};
-    private final String[] STATUSES = {"Booked","Completed","Cancelled"};
+
+    private AppointmentViewModel appointmentViewModel;
+    private PetViewModel petViewModel;
+    private ServiceViewModel serviceViewModel;
+    private StoreViewModel storeViewModel;
+    private CustomerViewModel customerViewModel;
+    private UserViewModel userViewModel;
+
+    @Override
+    public void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        appointmentViewModel = new ViewModelProvider(this).get(AppointmentViewModel.class);
+        petViewModel = new ViewModelProvider(this).get(PetViewModel.class);
+        serviceViewModel = new ViewModelProvider(this).get(ServiceViewModel.class);
+        storeViewModel = new ViewModelProvider(this).get(StoreViewModel.class);
+        customerViewModel = new ViewModelProvider(this).get(CustomerViewModel.class);
+        userViewModel = new ViewModelProvider(this).get(UserViewModel.class);
+    }
 
     @Override
     public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
-        View view = inflater.inflate(R.layout.fragment_appointment_detail, container, false);
-        initViews(view);
+        binding = FragmentAppointmentDetailBinding.inflate(inflater, container, false);
+        return binding.getRoot();
+    }
+
+    @Override
+    public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
+        super.onViewCreated(view, savedInstanceState);
         setupSpinners();
         setupDatePicker();
-        loadData();
+        loadSpinnersData();
         handleArguments();
 
-        btnBack.setOnClickListener(v -> navigateBack());
-        btnSave.setOnClickListener(v -> saveAppointment());
-        btnDelete.setOnClickListener(v -> confirmDelete());
-        return view;
+        binding.btnApptBack.setOnClickListener(v -> navigateBack());
+        binding.btnSaveAppointment.setOnClickListener(v -> saveAppointment());
+        binding.btnDeleteAppointment.setOnClickListener(v -> confirmDelete());
     }
 
-    private void initViews(View v) {
-        tvMode           = v.findViewById(R.id.tvApptMode);
-        tvAppointmentId  = v.findViewById(R.id.tvAppointmentId);
-        etAppointmentDate= v.findViewById(R.id.etAppointmentDate);
-        spinnerPet       = v.findViewById(R.id.spinnerPet);
-        spinnerService   = v.findViewById(R.id.spinnerService);
-        spinnerStatus    = v.findViewById(R.id.spinnerAppointmentStatus);
-        spinnerHour      = v.findViewById(R.id.spinnerHour);
-        spinnerMinute    = v.findViewById(R.id.spinnerMinute);
-        spinnerCustomer  = v.findViewById(R.id.spinnerCustomer);
-        spinnerStore     = v.findViewById(R.id.spinnerStore);
-        btnSave          = v.findViewById(R.id.btnSaveAppointment);
-        btnDelete        = v.findViewById(R.id.btnDeleteAppointment);
-        btnBack          = v.findViewById(R.id.btnApptBack);
+    @Override
+    public void onDestroyView() {
+        super.onDestroyView();
+        binding = null;
     }
 
+    /**
+     * Configures the adapters for spinners.
+     */
     private void setupSpinners() {
-        spinnerStatus.setAdapter(new ArrayAdapter<>(requireContext(),
-                android.R.layout.simple_spinner_item, STATUSES));
+        SpinnerUtils.setupStringSpinner(requireContext(), binding.spinnerAppointmentStatus,
+                new String[]{"Booked", "Completed", "Cancelled", "Missed"});
 
         String[] hours = new String[HOURS.length];
         for (int i = 0; i < HOURS.length; i++)
             hours[i] = String.format("%02d:00", HOURS[i]);
-        spinnerHour.setAdapter(new ArrayAdapter<>(requireContext(),
-                android.R.layout.simple_spinner_item, hours));
-        spinnerMinute.setAdapter(new ArrayAdapter<>(requireContext(),
-                android.R.layout.simple_spinner_item, new String[]{"00","15","30","45"}));
+        SpinnerUtils.setupStringSpinner(requireContext(), binding.spinnerHour, hours);
+        SpinnerUtils.setupStringSpinner(requireContext(), binding.spinnerMinute, new String[]{"00","15","30","45"});
     }
 
+    /**
+     * Configures the date picker dialog for the appointment date field.
+     */
     private void setupDatePicker() {
-        etAppointmentDate.setOnClickListener(v -> {
+        binding.etAppointmentDate.setOnClickListener(v -> {
             Calendar c = Calendar.getInstance();
             DatePickerDialog d = new DatePickerDialog(requireContext(),
-                    (dp,y,m,d1) -> etAppointmentDate.setText(
+                    (dp,y,m,d1) -> binding.etAppointmentDate.setText(
                             String.format("%04d-%02d-%02d", y, m+1, d1)),
                     c.get(Calendar.YEAR), c.get(Calendar.MONTH),
                     c.get(Calendar.DAY_OF_MONTH));
@@ -97,218 +125,233 @@ public class AppointmentDetailFragment extends Fragment {
         });
     }
 
-    private void loadData() {
+    /**
+     * Fetches all required data for spinners from the backend.
+     */
+    private void loadSpinnersData() {
         loadPets();
         loadServices();
         loadCustomers();
         loadStores();
-        loadAllAppointments();
+        loadStaff();
     }
 
+    /**
+     * Loads the list of pets from the ViewModel.
+     */
     private void loadPets() {
-        RetrofitClient.getPetApi(requireContext()).getAllPets(0, 200)
-                .enqueue(new Callback<PageResponse<PetDTO>>() {
-                    public void onResponse(Call<PageResponse<PetDTO>> c, Response<PageResponse<PetDTO>> r) {
-                        if (r.isSuccessful() && r.body() != null) {
-                            petList = r.body().getContent();
-                            populatePetSpinner();
-                        }
-                    }
-                    public void onFailure(Call<PageResponse<PetDTO>> c, Throwable t) {
-                        Log.e("APPT", "Pet load failed: " + t.getMessage());
-                    }
-                });
-    }
-
-    private void populatePetSpinner() {
-        List<String> names = new ArrayList<>();
-        names.add("-- Select Pet --");
-        for (PetDTO p : petList) names.add(p.getPetName());
-        spinnerPet.setAdapter(new ArrayAdapter<>(requireContext(),
-                android.R.layout.simple_spinner_item, names));
-        if (preselectedPetId != -1) {
-            for (int i = 0; i < petList.size(); i++) {
-                if (petList.get(i).getPetId().equals(preselectedPetId)) {
-                    spinnerPet.setSelection(i + 1); break;
-                }
+        petViewModel.getAllPets(0, 200, null, null, null, null, "petName").observe(getViewLifecycleOwner(), resource -> {
+            if (resource.status == Resource.Status.SUCCESS && resource.data != null) {
+                petList = resource.data.getContent();
+                refreshPetSpinner();
             }
-        }
+        });
     }
 
+    /**
+     * Populates the pet selection spinner.
+     */
+    private void refreshPetSpinner() {
+        SpinnerUtils.populateSpinner(requireContext(), binding.spinnerPet, petList,
+                PetDTO::getPetName, "-- Select Pet --",
+                preselectedPetId, PetDTO::getPetId);
+    }
+
+    /**
+     * Loads the list of services from the API.
+     */
     private void loadServices() {
-        RetrofitClient.getServiceApi(requireContext()).getAllServices(0, 200)
-                .enqueue(new Callback<PageResponse<ServiceDTO>>() {
-                    public void onResponse(Call<PageResponse<ServiceDTO>> c, Response<PageResponse<ServiceDTO>> r) {
-                        if (r.isSuccessful() && r.body() != null) {
-                            serviceList = r.body().getContent();
-                            populateServiceSpinner();
-                        }
-                    }
-                    public void onFailure(Call<PageResponse<ServiceDTO>> c, Throwable t) {
-                        Log.e("APPT", "Service load failed: " + t.getMessage());
-                    }
-                });
-    }
-
-    private void populateServiceSpinner() {
-        List<String> names = new ArrayList<>();
-        names.add("-- Select Service --");
-        for (ServiceDTO s : serviceList) names.add(s.getServiceName());
-        spinnerService.setAdapter(new ArrayAdapter<>(requireContext(),
-                android.R.layout.simple_spinner_item, names));
-        if (preselectedServiceId != -1) {
-            for (int i = 0; i < serviceList.size(); i++) {
-                if (serviceList.get(i).getServiceId().equals(preselectedServiceId)) {
-                    spinnerService.setSelection(i + 1); break;
-                }
+        serviceViewModel.getAllServices(0, 200, null, "serviceName").observe(getViewLifecycleOwner(), resource -> {
+            if (resource.status == Resource.Status.SUCCESS && resource.data != null) {
+                serviceList = resource.data.getContent();
+                refreshServiceSpinner();
             }
-        }
+        });
     }
 
+    /**
+     * Populates the service selection spinner.
+     */
+    private void refreshServiceSpinner() {
+        SpinnerUtils.populateSpinner(requireContext(), binding.spinnerService, serviceList,
+                ServiceDTO::getServiceName, "-- Select Service --",
+                preselectedServiceId, ServiceDTO::getServiceId);
+    }
+
+    /**
+     * Loads the list of customers from the API.
+     */
     private void loadCustomers() {
-        RetrofitClient.getCustomerApi(requireContext()).getAllCustomers(0, 200)
-                .enqueue(new Callback<PageResponse<CustomerDTO>>() {
-                    public void onResponse(Call<PageResponse<CustomerDTO>> c, Response<PageResponse<CustomerDTO>> r) {
-                        if (r.isSuccessful() && r.body() != null) {
-                            customerList = r.body().getContent();
-                            populateCustomerSpinner();
-                        }
-                    }
-                    public void onFailure(Call<PageResponse<CustomerDTO>> c, Throwable t) {
-                        Log.e("APPT", "Customer load failed: " + t.getMessage());
-                    }
-                });
-    }
-
-    private void populateCustomerSpinner() {
-        List<String> names = new ArrayList<>();
-        names.add("-- Select Customer --");
-        for (CustomerDTO c : customerList)
-            names.add(c.getFirstName() + " " + c.getLastName());
-        spinnerCustomer.setAdapter(new ArrayAdapter<>(requireContext(),
-                android.R.layout.simple_spinner_item, names));
-        if (preselectedCustomerId != -1) {
-            for (int i = 0; i < customerList.size(); i++) {
-                if (customerList.get(i).getCustomerId().equals(preselectedCustomerId)) {
-                    spinnerCustomer.setSelection(i + 1); break;
-                }
+        customerViewModel.getAllCustomers(0, 200).observe(getViewLifecycleOwner(), resource -> {
+            if (resource.status == Resource.Status.SUCCESS && resource.data != null) {
+                customerList = resource.data.getContent();
+                refreshCustomerSpinner();
             }
-        }
+        });
     }
 
+    /**
+     * Populates the customer selection spinner.
+     */
+    private void refreshCustomerSpinner() {
+        SpinnerUtils.populateSpinner(requireContext(), binding.spinnerCustomer, customerList,
+                item -> item.getFirstName() + " " + item.getLastName(),
+                "-- Select Customer --",
+                preselectedCustomerId, CustomerDTO::getCustomerId);
+    }
+
+    /**
+     * Loads the list of stores from the API.
+     */
     private void loadStores() {
-        RetrofitClient.getStoreApi(requireContext()).getAllStores(0, 50)
-                .enqueue(new Callback<PageResponse<StoreDTO>>() {
-                    public void onResponse(Call<PageResponse<StoreDTO>> c, Response<PageResponse<StoreDTO>> r) {
-                        if (r.isSuccessful() && r.body() != null) {
-                            storeList = r.body().getContent();
-                            populateStoreSpinner();
-                        }
-                    }
-                    public void onFailure(Call<PageResponse<StoreDTO>> c, Throwable t) {
-                        Log.e("APPT", "Store load failed: " + t.getMessage());
-                    }
-                });
-    }
-
-    private void populateStoreSpinner() {
-        List<String> names = new ArrayList<>();
-        names.add("-- Select Store --");
-        for (StoreDTO s : storeList) names.add(s.getStoreName());
-        spinnerStore.setAdapter(new ArrayAdapter<>(requireContext(),
-                android.R.layout.simple_spinner_item, names));
-        if (preselectedStoreId != -1) {
-            for (int i = 0; i < storeList.size(); i++) {
-                if (storeList.get(i).getStoreId().equals(preselectedStoreId)) {
-                    spinnerStore.setSelection(i + 1); break;
-                }
+        storeViewModel.getAllStores(0, 50).observe(getViewLifecycleOwner(), resource -> {
+            if (resource.status == Resource.Status.SUCCESS && resource.data != null) {
+                storeList = resource.data.getContent();
+                refreshStoreSpinner();
             }
-        }
+        });
     }
 
-    private void loadAllAppointments() {
-        RetrofitClient.getAppointmentApi(requireContext()).getAllAppointments(0, 500)
-                .enqueue(new Callback<PageResponse<AppointmentDTO>>() {
-                    public void onResponse(Call<PageResponse<AppointmentDTO>> c, Response<PageResponse<AppointmentDTO>> r) {
-                        if (r.isSuccessful() && r.body() != null)
-                            allAppointments = r.body().getContent();
-                    }
-                    public void onFailure(Call<PageResponse<AppointmentDTO>> c, Throwable t) {}
-                });
+    /**
+     * Populates the store selection spinner.
+     */
+    private void refreshStoreSpinner() {
+        SpinnerUtils.populateSpinner(requireContext(), binding.spinnerStore, storeList,
+                StoreDTO::getStoreName, "-- Select Store --",
+                preselectedStoreId, StoreDTO::getStoreId);
     }
 
+    /**
+     * Loads the list of staff from the API.
+     */
+    private void loadStaff() {
+        userViewModel.getUsers("STAFF", 0, 100).observe(getViewLifecycleOwner(), resource -> {
+            if (resource.status == Resource.Status.SUCCESS && resource.data != null) {
+                staffList = resource.data.getContent();
+                refreshStaffSpinner();
+            }
+        });
+    }
+
+    /**
+     * Populates the staff selection spinner.
+     */
+    private void refreshStaffSpinner() {
+        SpinnerUtils.populateSpinner(requireContext(), binding.spinnerStaff, staffList,
+                UserDTO::getFullName, "-- Select Staff --",
+                preselectedStaffId, UserDTO::getId);
+    }
+
+    /**
+     * Handles arguments to determine if the fragment is in edit or add mode.
+     */
     private void handleArguments() {
         Bundle a = getArguments();
         if (a != null && a.containsKey("appointmentId")) {
             isEditing = true;
-            appointmentId       = a.getLong("appointmentId");
-            preselectedPetId    = a.getLong("petId", -1);
-            preselectedServiceId= a.getLong("serviceId", -1);
-            preselectedCustomerId = a.getLong("customerId", -1);
-            preselectedStoreId  = a.getLong("storeId", -1);
-
-            tvMode.setText("Edit Appointment");
-            tvAppointmentId.setText("ID: " + appointmentId);
-            tvAppointmentId.setVisibility(View.VISIBLE);
-            etAppointmentDate.setText(a.getString("appointmentDate"));
-            btnDelete.setVisibility(View.VISIBLE);
-
-            // Pre-fill time spinners
-            String time = a.getString("appointmentTime", "09:00");
-            if (time.length() > 5) time = time.substring(0, 5);
-            String[] parts = time.split(":");
-            if (parts.length == 2) {
-                int hour = Integer.parseInt(parts[0]);
-                int min  = Integer.parseInt(parts[1]);
-                for (int i = 0; i < HOURS.length; i++)
-                    if (HOURS[i] == hour) { spinnerHour.setSelection(i); break; }
-                for (int i = 0; i < MINUTES.length; i++)
-                    if (MINUTES[i] == min) { spinnerMinute.setSelection(i); break; }
-            }
-
-            // Pre-fill status
-            String status = a.getString("appointmentStatus", "Booked");
-            for (int i = 0; i < STATUSES.length; i++)
-                if (STATUSES[i].equals(status)) { spinnerStatus.setSelection(i); break; }
-
+            appointmentId = a.getLong("appointmentId");
+            binding.tvApptMode.setText("Edit Appointment");
+            binding.tvAppointmentId.setText("ID: " + appointmentId);
+            binding.tvAppointmentId.setVisibility(View.VISIBLE);
+            binding.btnDeleteAppointment.setVisibility(View.VISIBLE);
+            loadAppointmentData();
         } else {
-            tvMode.setText("Add Appointment");
-            btnDelete.setVisibility(View.GONE);
-            tvAppointmentId.setVisibility(View.GONE);
+            binding.tvApptMode.setText("Add Appointment");
+            binding.btnDeleteAppointment.setVisibility(View.GONE);
+            binding.tvAppointmentId.setVisibility(View.GONE);
         }
     }
 
+    /**
+     * Fetches specific appointment details from the backend using the ID.
+     */
+    private void loadAppointmentData() {
+        appointmentViewModel.getAppointmentById(appointmentId).observe(getViewLifecycleOwner(), resource -> {
+            if (resource == null) return;
+            if (resource.status == Resource.Status.SUCCESS && resource.data != null) {
+                AppointmentDTO a = resource.data;
+                preselectedPetId = (a.getPetId() != null) ? a.getPetId() : -1;
+                preselectedServiceId = (a.getServiceId() != null) ? a.getServiceId() : -1;
+                preselectedCustomerId = (a.getCustomerId() != null) ? a.getCustomerId() : -1;
+                preselectedStoreId = (a.getStoreId() != null) ? a.getStoreId() : -1;
+                preselectedStaffId = (a.getEmployeeId() != null) ? a.getEmployeeId() : -1;
+
+                binding.etAppointmentDate.setText(a.getAppointmentDate());
+
+                // Pre-fill time spinners
+                String time = a.getAppointmentTime() != null ? a.getAppointmentTime() : "09:00";
+                if (time.length() > 5) time = time.substring(0, 5);
+                String[] parts = time.split(":");
+                if (parts.length == 2) {
+                    try {
+                        int hour = Integer.parseInt(parts[0]);
+                        int min = Integer.parseInt(parts[1]);
+                        for (int i = 0; i < HOURS.length; i++)
+                            if (HOURS[i] == hour) { binding.spinnerHour.setSelection(i); break; }
+                        for (int i = 0; i < MINUTES.length; i++)
+                            if (MINUTES[i] == min) { binding.spinnerMinute.setSelection(i); break; }
+                    } catch (NumberFormatException ignored) {}
+                }
+
+                // Match Title labels with backend values
+                String status = a.getAppointmentStatus();
+                if (status != null && !status.isEmpty()) {
+                    String formattedStatus = status.substring(0, 1).toUpperCase() + status.substring(1).toLowerCase();
+                    SpinnerUtils.setSelectionByValue(binding.spinnerAppointmentStatus, formattedStatus);
+                }
+
+                refreshPetSpinner();
+                refreshServiceSpinner();
+                refreshCustomerSpinner();
+                refreshStoreSpinner();
+                refreshStaffSpinner();
+            } else if (resource.status == Resource.Status.ERROR) {
+                Toast.makeText(getContext(), "Failed to load appointment: " + resource.message, Toast.LENGTH_SHORT).show();
+            }
+        });
+    }
+
+    /**
+     * Validates input and saves the appointment to the backend.
+     */
     private void saveAppointment() {
-        if (spinnerCustomer.getSelectedItemPosition() == 0) {
+        if (binding.spinnerCustomer.getSelectedItemPosition() == 0) {
             Toast.makeText(getContext(), "Select a customer", Toast.LENGTH_SHORT).show(); return;
         }
-        if (spinnerStore.getSelectedItemPosition() == 0) {
+        if (binding.spinnerStore.getSelectedItemPosition() == 0) {
             Toast.makeText(getContext(), "Select a store", Toast.LENGTH_SHORT).show(); return;
         }
-        if (spinnerPet.getSelectedItemPosition() == 0) {
+        if (binding.spinnerPet.getSelectedItemPosition() == 0) {
             Toast.makeText(getContext(), "Select a pet", Toast.LENGTH_SHORT).show(); return;
         }
-        if (spinnerService.getSelectedItemPosition() == 0) {
+        if (binding.spinnerService.getSelectedItemPosition() == 0) {
             Toast.makeText(getContext(), "Select a service", Toast.LENGTH_SHORT).show(); return;
         }
-        String date = etAppointmentDate.getText().toString().trim();
+        String date = binding.etAppointmentDate.getText().toString().trim();
         if (date.isEmpty()) {
             Toast.makeText(getContext(), "Select a date", Toast.LENGTH_SHORT).show(); return;
         }
 
-        CustomerDTO customer = customerList.get(spinnerCustomer.getSelectedItemPosition() - 1);
-        StoreDTO store       = storeList.get(spinnerStore.getSelectedItemPosition() - 1);
-        PetDTO pet           = petList.get(spinnerPet.getSelectedItemPosition() - 1);
-        ServiceDTO service   = serviceList.get(spinnerService.getSelectedItemPosition() - 1);
+        CustomerDTO customer = customerList.get(binding.spinnerCustomer.getSelectedItemPosition() - 1);
+        StoreDTO store       = storeList.get(binding.spinnerStore.getSelectedItemPosition() - 1);
+        PetDTO pet           = petList.get(binding.spinnerPet.getSelectedItemPosition() - 1);
+        ServiceDTO service   = serviceList.get(binding.spinnerService.getSelectedItemPosition() - 1);
+        
+        Long employeeId = null;
+        if (binding.spinnerStaff.getSelectedItemPosition() > 0) {
+            employeeId = staffList.get(binding.spinnerStaff.getSelectedItemPosition() - 1).getId();
+        }
 
         String time = String.format("%02d:%02d",
-                HOURS[spinnerHour.getSelectedItemPosition()],
-                MINUTES[spinnerMinute.getSelectedItemPosition()]);
-        String status = STATUSES[spinnerStatus.getSelectedItemPosition()];
+                HOURS[binding.spinnerHour.getSelectedItemPosition()],
+                MINUTES[binding.spinnerMinute.getSelectedItemPosition()]);
+        
+        // Get status and convert to uppercase for backend
+        String status = binding.spinnerAppointmentStatus.getSelectedItem().toString().toUpperCase();
 
 
-        // Validate future date+time if status is Booked
-        if ("Booked".equalsIgnoreCase(status)) {
+        // Validate future date+time if status is BOOKED
+        if ("BOOKED".equalsIgnoreCase(status)) {
             try {
                 String[] dateParts = date.split("-");
                 String[] timeParts = time.split(":");
@@ -322,7 +365,7 @@ public class AppointmentDetailFragment extends Fragment {
                         0
                 );
                 if (selected.before(Calendar.getInstance())) {
-                    showErrorDialog("Invalid Time",
+                    DialogUtils.showInfoDialog(requireContext(), "Invalid Time",
                             "Booked appointments must be in the future. " +
                                     "Please select a future date and time.");
                     return;
@@ -337,107 +380,80 @@ public class AppointmentDetailFragment extends Fragment {
                 customer.getCustomerId(),
                 store.getStoreId(),
                 service.getServiceId(),
+                employeeId,
                 date,
                 time,
                 status,
-                Collections.singletonList(pet.getPetId())
+                pet.getPetId()
         );
 
-        Log.d("APPT_SAVE", "customerId=" + customer.getCustomerId()
-                + " storeId=" + store.getStoreId()
-                + " serviceId=" + service.getServiceId()
-                + " petId=" + pet.getPetId()
-                + " date=" + date + " time=" + time);
+        androidx.lifecycle.Observer<Resource<AppointmentDTO>> observer = resource -> {
+            if (resource.status == Resource.Status.SUCCESS) {
+                Toast.makeText(getContext(), isEditing ? "Updated" : "Saved", Toast.LENGTH_SHORT).show();
+                navigateBack();
+            } else if (resource.status == Resource.Status.ERROR) {
+                handleSaveError(resource.message);
+            }
+        };
 
-        AppointmentApi api = RetrofitClient.getAppointmentApi(requireContext());
         if (isEditing) {
-            api.updateAppointment(appointmentId, dto).enqueue(simpleCallback("Updated"));
+            appointmentViewModel.updateAppointment(appointmentId, dto).observe(getViewLifecycleOwner(), observer);
         } else {
-            api.createAppointment(dto).enqueue(simpleCallback("Saved"));
+            appointmentViewModel.createAppointment(dto).observe(getViewLifecycleOwner(), observer);
         }
     }
 
-    private Callback<AppointmentDTO> simpleCallback(String msg) {
-        return new Callback<>() {
-            public void onResponse(Call<AppointmentDTO> c, Response<AppointmentDTO> r) {
-                Log.d("APPT_SAVE", "Response: " + r.code());
-                if (r.isSuccessful()) {
-                    Toast.makeText(getContext(), msg, Toast.LENGTH_SHORT).show();
-                    navigateBack();
-                } else {
-                    try {
-                        String errorBody = r.errorBody().string();
-                        Log.e("APPT_SAVE", "Error: " + errorBody);
-
-                        // Show proper dialog based on error type
-                        if (errorBody.toLowerCase().contains("future")) {
-                            showErrorDialog("Invalid Date/Time",
-                                    "Booked appointments must be scheduled in the future. " +
-                                            "Please select a future date and time.");
-                      //------------------------------------------
-                        } else if (errorBody.toLowerCase().contains("not available") ||
-                                errorBody.toLowerCase().contains("time is not available")) {
-                            showNoAvailabilityDialog();
-                        } else if (r.code() == 404) {
-                            showErrorDialog("Not Found",
-                                    "The selected pet, customer or service was not found.");
-                        } else if (r.code() == 403) {
-                            showErrorDialog("Access Denied",
-                                    "You don't have permission to perform this action.");
-                        } else if (r.code() == 400) {
-                            showErrorDialog("Invalid Request", errorBody);
-                        } else {
-                            showErrorDialog("Error", "Something went wrong. Please try again.");
-                        }
-                        //-----------------------------
-                    } catch (Exception e) {
-                        Log.e("APPT_SAVE", "Failed to read error body");
-                        showErrorDialog("Error", "Something went wrong. Please try again.");
-                    }
-                }
+    /**
+     * Handles errors that occur during the saving process.
+     */
+    private void handleSaveError(String errorMessage) {
+        if (errorMessage != null) {
+            Log.e("APPT_SAVE", "Error: " + errorMessage);
+            if (errorMessage.toLowerCase().contains("future")) {
+                DialogUtils.showInfoDialog(requireContext(), "Invalid Date/Time",
+                        "Booked appointments must be scheduled in the future.");
+            } else if (errorMessage.toLowerCase().contains("not available")) {
+                showNoAvailabilityDialog();
+            } else {
+                Toast.makeText(getContext(), "Operation failed", Toast.LENGTH_SHORT).show();
             }
-
-            public void onFailure(Call<AppointmentDTO> c, Throwable t) {
-                Log.e("APPT_SAVE", "Failure: " + t.getMessage());
-                Toast.makeText(getContext(), "Network error", Toast.LENGTH_SHORT).show();
-            }
-        };
+        } else {
+            Toast.makeText(getContext(), "Something went wrong", Toast.LENGTH_SHORT).show();
+        }
     }
 
+    /**
+     * Shows a specialized dialog when a time slot is not available.
+     */
     private void showNoAvailabilityDialog() {
-        new AlertDialog.Builder(requireContext())
+        new androidx.appcompat.app.AlertDialog.Builder(requireContext())
                 .setTitle("No Availability")
-                .setMessage("This time slot is already booked for the selected service and store. Please choose a different time or date.")
+                .setMessage("This time slot is already booked. Please choose a different time or date.")
                 .setPositiveButton("Change Time", (d, w) -> d.dismiss())
                 .setNegativeButton("Cancel Booking", (d, w) -> navigateBack())
                 .setCancelable(false)
                 .show();
     }
 
-    private void showErrorDialog(String title, String message) {
-        new AlertDialog.Builder(requireContext())
-                .setTitle(title)
-                .setMessage(message)
-                .setPositiveButton("OK", null)
-                .show();
-    }
+    /**
+     * Shows a confirmation dialog and handles the deletion of an appointment.
+     */
     private void confirmDelete() {
-        new AlertDialog.Builder(requireContext())
-                .setTitle("Delete Appointment?")
-                .setPositiveButton("Yes", (d, w) ->
-                        RetrofitClient.getAppointmentApi(requireContext())
-                                .deleteAppointment(appointmentId)
-                                .enqueue(new Callback<Void>() {
-                                    public void onResponse(Call<Void> c, Response<Void> r) { navigateBack(); }
-                                    public void onFailure(Call<Void> c, Throwable t) {
-                                        Toast.makeText(getContext(), "Delete failed", Toast.LENGTH_SHORT).show();
-                                    }
-                                }))
-                .setNegativeButton("No", null).show();
+        DialogUtils.showDeleteConfirmDialog(requireContext(), "Appointment", () ->
+                appointmentViewModel.deleteAppointment(appointmentId).observe(getViewLifecycleOwner(), resource -> {
+                    if (resource.status == Resource.Status.SUCCESS) {
+                        Toast.makeText(getContext(), "Deleted", Toast.LENGTH_SHORT).show();
+                        navigateBack();
+                    } else if (resource.status == Resource.Status.ERROR) {
+                        Toast.makeText(getContext(), "Delete failed", Toast.LENGTH_SHORT).show();
+                    }
+                }));
     }
 
+    /**
+     * Navigates back to the previous screen.
+     */
     private void navigateBack() {
-        ListFragment lf = (ListFragment) getParentFragment();
-        if (lf != null) lf.getChildFragmentManager().popBackStack();
+        NavHostFragment.findNavController(this).popBackStack();
     }
-}
+}

android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/InventoryDetailFragment.java

@@ -1,291 +1,236 @@
 package com.example.petstoremobile.fragments.listfragments.detailfragments;
 
 import android.os.Bundle;
-import android.os.Handler;
-import android.os.Looper;
-import android.text.Editable;
-import android.text.TextWatcher;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
-import android.widget.ArrayAdapter;
-import android.widget.AutoCompleteTextView;
-import android.widget.Button;
-import android.widget.TextView;
 import android.widget.Toast;
 
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 import androidx.appcompat.app.AlertDialog;
 import androidx.fragment.app.Fragment;
+import androidx.lifecycle.ViewModelProvider;
+import androidx.navigation.fragment.NavHostFragment;
 
-import com.example.petstoremobile.R;
-import com.example.petstoremobile.api.InventoryApi;
-import com.example.petstoremobile.api.ProductApi;
-import com.example.petstoremobile.api.RetrofitClient;
+import com.example.petstoremobile.databinding.FragmentInventoryDetailBinding;
 import com.example.petstoremobile.dtos.InventoryDTO;
-import com.example.petstoremobile.dtos.InventoryRequest;
-import com.example.petstoremobile.dtos.PageResponse;
 import com.example.petstoremobile.dtos.ProductDTO;
-import com.example.petstoremobile.fragments.ListFragment;
-import com.example.petstoremobile.fragments.listfragments.InventoryFragment;
+import com.example.petstoremobile.dtos.StoreDTO;
+import com.example.petstoremobile.utils.InputValidator;
+import com.example.petstoremobile.utils.Resource;
+import com.example.petstoremobile.utils.SpinnerUtils;
+import com.example.petstoremobile.viewmodels.InventoryViewModel;
+import com.example.petstoremobile.viewmodels.ProductViewModel;
+import com.example.petstoremobile.viewmodels.StoreViewModel;
 
 import java.util.ArrayList;
 import java.util.List;
 
-import retrofit2.Call;
-import retrofit2.Callback;
-import retrofit2.Response;
+import dagger.hilt.android.AndroidEntryPoint;
 
+/**
+ * Fragment for displaying and editing inventory item details.
+ */
+@AndroidEntryPoint
 public class InventoryDetailFragment extends Fragment {
 
-    private TextView tvMode, tvInventoryId, tvProductInfo;
-    private AutoCompleteTextView etProductSearch;
-    private android.widget.EditText etQuantity;
-    private Button btnSave, btnDelete, btnBack;
+    private FragmentInventoryDetailBinding binding;
 
-    private InventoryApi inventoryApi;
-    private ProductApi productApi;
-    private InventoryFragment inventoryFragment;
+    private InventoryViewModel inventoryViewModel;
+    private ProductViewModel productViewModel;
+    private StoreViewModel storeViewModel;
 
     private boolean isEditing = false;
     private long inventoryId = -1;
+    private long preselectedStoreId = -1;
+    private long preselectedProductId = -1;
 
-    // The product selected from the dropdown
-    private ProductDTO selectedProduct = null;
+    private List<StoreDTO> storeList = new ArrayList<>();
+    private List<ProductDTO> productList = new ArrayList<>();
 
-    // For debouncing product search
-    private final Handler searchHandler = new Handler(Looper.getMainLooper());
-    private Runnable searchRunnable;
+    /**
+     * Initializes the view models.
+     */
+    @Override
+    public void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        inventoryViewModel = new ViewModelProvider(this).get(InventoryViewModel.class);
+        productViewModel = new ViewModelProvider(this).get(ProductViewModel.class);
+        storeViewModel = new ViewModelProvider(this).get(StoreViewModel.class);
+    }
 
-    // Dropdown list
-    private final List<ProductDTO> productSuggestions = new ArrayList<>();
-    private ArrayAdapter<String> dropdownAdapter;
+    /**
+     * Inflates the layout.
+     */
+    @Override
+    public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
+                             Bundle savedInstanceState) {
+        binding = FragmentInventoryDetailBinding.inflate(inflater, container, false);
+        return binding.getRoot();
+    }
 
-    public void setInventoryFragment(InventoryFragment fragment) {
-        this.inventoryFragment = fragment;
+    /**
+     * Sets up UI components after the view is created.
+     */
+    @Override
+    public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
+        super.onViewCreated(view, savedInstanceState);
+
+        loadSpinnersData();
+        handleArguments();
+
+        binding.btnInventoryBack.setOnClickListener(v -> navigateBack());
+        binding.btnSaveInventory.setOnClickListener(v -> saveInventory());
+        binding.btnDeleteInventory.setOnClickListener(v -> confirmDelete());
     }
 
     @Override
-    public View onCreateView(LayoutInflater inflater, ViewGroup container,
-                             Bundle savedInstanceState) {
-        View view = inflater.inflate(R.layout.fragment_inventory_detail, container, false);
-
-        inventoryApi = RetrofitClient.getInventoryApi(requireContext());
-        productApi = RetrofitClient.getProductApi(requireContext());
-
-        initViews(view);
-        setupProductSearch();
-        handleArguments();
-
-        btnBack.setOnClickListener(v -> navigateBack());
-        btnSave.setOnClickListener(v -> saveInventory());
-        btnDelete.setOnClickListener(v -> confirmDelete());
-
-        return view;
+    public void onDestroyView() {
+        super.onDestroyView();
+        binding = null;
     }
 
-    private void initViews(View view) {
-        tvMode = view.findViewById(R.id.tvInventoryMode);
-        tvInventoryId = view.findViewById(R.id.tvInventoryId);
-        tvProductInfo = view.findViewById(R.id.tvProductInfo);
-        etProductSearch = view.findViewById(R.id.etProductSearch);
-        etQuantity = view.findViewById(R.id.etQuantity);
-        btnSave = view.findViewById(R.id.btnSaveInventory);
-        btnDelete = view.findViewById(R.id.btnDeleteInventory);
-        btnBack = view.findViewById(R.id.btnInventoryBack);
-
-        // Setup dropdown adapter
-        dropdownAdapter = new ArrayAdapter<>(requireContext(),
-                android.R.layout.simple_dropdown_item_1line, new ArrayList<>());
-        etProductSearch.setAdapter(dropdownAdapter);
-        etProductSearch.setThreshold(1); // start showing after 1 character
+    /**
+     * Fetches required data for spinners from the backend.
+     */
+    private void loadSpinnersData() {
+        loadStores();
+        loadProducts();
     }
 
-    // Product search dropdown
-    private void setupProductSearch() {
-        etProductSearch.addTextChangedListener(new TextWatcher() {
-            @Override
-            public void beforeTextChanged(CharSequence s, int i, int i1, int i2) {
-            }
-
-            @Override
-            public void afterTextChanged(Editable s) {
-            }
-
-            @Override
-            public void onTextChanged(CharSequence s, int start, int before, int count) {
-                // Clear selected product when user is typing again
-                selectedProduct = null;
-                tvProductInfo.setVisibility(View.GONE);
-
-                if (searchRunnable != null)
-                    searchHandler.removeCallbacks(searchRunnable);
-                String query = s.toString().trim();
-                if (query.isEmpty())
-                    return;
-
-                searchRunnable = () -> searchProducts(query);
-                searchHandler.postDelayed(searchRunnable, 400);
-            }
-        });
-
-        // When user picks an item from the dropdown
-        etProductSearch.setOnItemClickListener((parent, view, position, id) -> {
-            if (position < productSuggestions.size()) {
-                selectedProduct = productSuggestions.get(position);
-                // Show product details below the search box
-                tvProductInfo.setText(
-                        "ID: " + selectedProduct.getProdId()
-                                + "  •  " + selectedProduct.getCategoryName());
-                tvProductInfo.setVisibility(View.VISIBLE);
+    /**
+     * Loads the list of stores for the spinner.
+     */
+    private void loadStores() {
+        storeViewModel.getAllStores(0, 100).observe(getViewLifecycleOwner(), resource -> {
+            if (resource.status == Resource.Status.SUCCESS && resource.data != null) {
+                storeList = resource.data.getContent();
+                refreshStoreSpinner();
             }
         });
     }
 
-    private void searchProducts(String query) {
-        productApi.getAllProducts(query, 0, 20).enqueue(new Callback<PageResponse<ProductDTO>>() {
-            @Override
-            public void onResponse(Call<PageResponse<ProductDTO>> call,
-                                   Response<PageResponse<ProductDTO>> response) {
-                if (response.isSuccessful() && response.body() != null) {
-                    productSuggestions.clear();
-                    productSuggestions.addAll(response.body().getContent());
+    private void refreshStoreSpinner() {
+        SpinnerUtils.populateSpinner(requireContext(), binding.spinnerInventoryStore, storeList,
+                StoreDTO::getStoreName, "-- Select Store --",
+                preselectedStoreId, StoreDTO::getStoreId);
+    }
 
-                    // Build display strings: "Product Name (ID: X)"
-                    List<String> names = new ArrayList<>();
-                    for (ProductDTO p : productSuggestions) {
-                        names.add(p.getProdName() + " (ID: " + p.getProdId() + ")");
-                    }
-
-                    dropdownAdapter.clear();
-                    dropdownAdapter.addAll(names);
-                    dropdownAdapter.notifyDataSetChanged();
-                    etProductSearch.showDropDown();
-                }
-            }
-
-            @Override
-            public void onFailure(Call<PageResponse<ProductDTO>> call, Throwable t) {
-                Toast.makeText(getContext(), "Failed to load products", Toast.LENGTH_SHORT).show();
+    /**
+     * Loads the list of products for the spinner.
+     */
+    private void loadProducts() {
+        productViewModel.getAllProducts(null, null, 0, 500, "prodName").observe(getViewLifecycleOwner(), resource -> {
+            if (resource.status == Resource.Status.SUCCESS && resource.data != null) {
+                productList = resource.data.getContent();
+                refreshProductSpinner();
             }
         });
     }
 
-    // Arguments (edit mode)
+    private void refreshProductSpinner() {
+        SpinnerUtils.populateSpinner(requireContext(), binding.spinnerInventoryProduct, productList,
+                ProductDTO::getProdName, "-- Select Product --",
+                preselectedProductId, ProductDTO::getProdId);
+    }
 
+    /**
+     * Handles fragment arguments to determine if we are in edit or add mode.
+     */
     private void handleArguments() {
         Bundle args = getArguments();
         if (args != null && args.containsKey("inventoryId")) {
             isEditing = true;
             inventoryId = args.getLong("inventoryId");
 
-            tvMode.setText("Edit Inventory");
-            tvInventoryId.setText("Inventory ID: " + inventoryId);
-            tvInventoryId.setVisibility(View.VISIBLE);
+            binding.tvInventoryMode.setText("Edit Inventory");
+            binding.tvInventoryId.setText("Inventory ID: " + inventoryId);
+            binding.tvInventoryId.setVisibility(View.VISIBLE);
+            binding.btnDeleteInventory.setVisibility(View.VISIBLE);
+            binding.btnSaveInventory.setText("Save");
 
-            // Pre-fill search box with existing product name
-            String productName = args.getString("productName", "");
-            long prodId = args.getLong("prodId", -1);
-            etProductSearch.setText(productName);
-
-            // Show existing product info
-            if (prodId != -1) {
-                tvProductInfo.setText(
-                        "ID: " + prodId
-                                + "  •  " + args.getString("categoryName", ""));
-                tvProductInfo.setVisibility(View.VISIBLE);
-
-                // Build a minimal ProductDTO so selectedProduct is not null on save
-                selectedProduct = new ProductDTO(productName, null, null, null);
-                selectedProduct.setProdId(prodId);
-            }
-
-            etQuantity.setText(String.valueOf(args.getInt("quantity", 0)));
-            btnDelete.setVisibility(View.VISIBLE);
-            btnSave.setText("Save");
+            loadInventoryData();
         } else {
             isEditing = false;
-            tvMode.setText("Add Inventory");
-            tvInventoryId.setVisibility(View.GONE);
-            tvProductInfo.setVisibility(View.GONE);
-            btnDelete.setVisibility(View.GONE);
-            btnSave.setText("Add");
+            binding.tvInventoryMode.setText("Add Inventory");
+            binding.tvInventoryId.setVisibility(View.GONE);
+            binding.btnDeleteInventory.setVisibility(View.GONE);
+            binding.btnSaveInventory.setText("Add");
         }
     }
 
-    // Save
+    /**
+     * Loads existing inventory data from the backend.
+     */
+    private void loadInventoryData() {
+        inventoryViewModel.getInventoryById(inventoryId).observe(getViewLifecycleOwner(), resource -> {
+            if (resource == null) return;
+            if (resource.status == Resource.Status.SUCCESS && resource.data != null) {
+                InventoryDTO inv = resource.data;
+                binding.etQuantity.setText(String.valueOf(inv.getQuantity()));
+                preselectedStoreId = inv.getStoreId() != null ? inv.getStoreId() : -1;
+                preselectedProductId = inv.getProdId() != null ? inv.getProdId() : -1;
+                
+                refreshStoreSpinner();
+                refreshProductSpinner();
+            } else if (resource.status == Resource.Status.ERROR) {
+                Toast.makeText(getContext(), "Failed to load inventory: " + resource.message, Toast.LENGTH_SHORT).show();
+            }
+        });
+    }
+
+    /**
+     * Validates input and saves the current inventory item details to the backend.
+     */
     private void saveInventory() {
-        if (selectedProduct == null) {
-            etProductSearch.setError("Please select a product from the list");
-            etProductSearch.requestFocus();
+        if (binding.spinnerInventoryStore.getSelectedItemPosition() == 0) {
+            Toast.makeText(getContext(), "Please select a store", Toast.LENGTH_SHORT).show();
+            return;
+        }
+        if (binding.spinnerInventoryProduct.getSelectedItemPosition() == 0) {
+            Toast.makeText(getContext(), "Please select a product", Toast.LENGTH_SHORT).show();
             return;
         }
 
-        String quantityStr = etQuantity.getText().toString().trim();
-        if (quantityStr.isEmpty()) {
-            etQuantity.setError("Quantity is required");
-            etQuantity.requestFocus();
+        if (!InputValidator.isNotEmpty(binding.etQuantity, "Quantity") ||
+            !InputValidator.isPositiveInteger(binding.etQuantity, "Quantity")) {
             return;
         }
 
-        int quantity;
-        try {
-            quantity = Integer.parseInt(quantityStr);
-        } catch (NumberFormatException e) {
-            etQuantity.setError("Invalid quantity");
-            return;
-        }
+        int quantity = Integer.parseInt(binding.etQuantity.getText().toString().trim());
+        StoreDTO store = storeList.get(binding.spinnerInventoryStore.getSelectedItemPosition() - 1);
+        ProductDTO product = productList.get(binding.spinnerInventoryProduct.getSelectedItemPosition() - 1);
 
-        if (quantity < 0) {
-            etQuantity.setError("Quantity must be 0 or more");
-            etQuantity.requestFocus();
-            return;
-        }
-
-        InventoryRequest request = new InventoryRequest(selectedProduct.getProdId(), quantity);
+        InventoryDTO request = new InventoryDTO(product.getProdId(), store.getStoreId(), quantity);
         setButtonsEnabled(false);
 
         if (isEditing) {
-            inventoryApi.updateInventory(inventoryId, request).enqueue(new Callback<InventoryDTO>() {
-                @Override
-                public void onResponse(Call<InventoryDTO> call, Response<InventoryDTO> response) {
-                    setButtonsEnabled(true);
-                    if (response.isSuccessful()) {
-                        Toast.makeText(getContext(), "Inventory updated", Toast.LENGTH_SHORT).show();
-                        notifyParentAndGoBack();
-                    } else {
-                        Toast.makeText(getContext(), "Update failed: " + response.code(), Toast.LENGTH_SHORT).show();
-                    }
-                }
-
-                @Override
-                public void onFailure(Call<InventoryDTO> call, Throwable t) {
-                    setButtonsEnabled(true);
-                    Toast.makeText(getContext(), "Network error", Toast.LENGTH_SHORT).show();
+            inventoryViewModel.updateInventory(inventoryId, request).observe(getViewLifecycleOwner(), resource -> {
+                setButtonsEnabled(true);
+                if (resource.status == Resource.Status.SUCCESS) {
+                    Toast.makeText(getContext(), "Inventory updated", Toast.LENGTH_SHORT).show();
+                    navigateBack();
+                } else if (resource.status == Resource.Status.ERROR) {
+                    Toast.makeText(getContext(), "Error: " + resource.message, Toast.LENGTH_SHORT).show();
                 }
             });
         } else {
-            inventoryApi.createInventory(request).enqueue(new Callback<InventoryDTO>() {
-                @Override
-                public void onResponse(Call<InventoryDTO> call, Response<InventoryDTO> response) {
-                    setButtonsEnabled(true);
-                    if (response.isSuccessful()) {
-                        Toast.makeText(getContext(), "Inventory created", Toast.LENGTH_SHORT).show();
-                        notifyParentAndGoBack();
-                    } else {
-                        Toast.makeText(getContext(), "Create failed: " + response.code(), Toast.LENGTH_SHORT).show();
-                    }
-                }
-
-                @Override
-                public void onFailure(Call<InventoryDTO> call, Throwable t) {
-                    setButtonsEnabled(true);
-                    Toast.makeText(getContext(), "Network error", Toast.LENGTH_SHORT).show();
+            inventoryViewModel.createInventory(request).observe(getViewLifecycleOwner(), resource -> {
+                setButtonsEnabled(true);
+                if (resource.status == Resource.Status.SUCCESS) {
+                    Toast.makeText(getContext(), "Inventory created", Toast.LENGTH_SHORT).show();
+                    navigateBack();
+                } else if (resource.status == Resource.Status.ERROR) {
+                    Toast.makeText(getContext(), "Error: " + resource.message, Toast.LENGTH_SHORT).show();
                 }
             });
         }
     }
 
-    // Delete
+    /**
+     * Shows a confirmation dialog before deleting an inventory item.
+     */
     private void confirmDelete() {
         new AlertDialog.Builder(requireContext())
                 .setTitle("Delete inventory item?")
@@ -295,45 +240,35 @@ public class InventoryDetailFragment extends Fragment {
                 .show();
     }
 
+    /**
+     * Sends a request to the API to delete the inventory item.
+     */
     private void deleteInventory() {
         setButtonsEnabled(false);
-        inventoryApi.deleteInventory(inventoryId).enqueue(new Callback<Void>() {
-            @Override
-            public void onResponse(Call<Void> call, Response<Void> response) {
-                setButtonsEnabled(true);
-                if (response.isSuccessful()) {
-                    Toast.makeText(getContext(), "Inventory deleted", Toast.LENGTH_SHORT).show();
-                    notifyParentAndGoBack();
-                } else {
-                    Toast.makeText(getContext(), "Delete failed: " + response.code(), Toast.LENGTH_SHORT).show();
-                }
-            }
-
-            @Override
-            public void onFailure(Call<Void> call, Throwable t) {
-                setButtonsEnabled(true);
-                Toast.makeText(getContext(), "Network error", Toast.LENGTH_SHORT).show();
+        inventoryViewModel.deleteInventory(inventoryId).observe(getViewLifecycleOwner(), resource -> {
+            setButtonsEnabled(true);
+            if (resource.status == Resource.Status.SUCCESS) {
+                Toast.makeText(getContext(), "Inventory deleted", Toast.LENGTH_SHORT).show();
+                navigateBack();
+            } else if (resource.status == Resource.Status.ERROR) {
+                Toast.makeText(getContext(), "Delete failed: " + resource.message, Toast.LENGTH_SHORT).show();
             }
         });
     }
 
-    // Helpers
-
-    private void notifyParentAndGoBack() {
-        if (inventoryFragment != null)
-            inventoryFragment.onInventoryChanged();
-        navigateBack();
-    }
-
+    /**
+     * Navigates back to the previous fragment.
+     */
     private void navigateBack() {
-        ListFragment lf = (ListFragment) getParentFragment();
-        if (lf != null)
-            lf.getChildFragmentManager().popBackStack();
+        NavHostFragment.findNavController(this).popBackStack();
     }
 
+    /**
+     * Enables or disables action buttons.
+     */
     private void setButtonsEnabled(boolean enabled) {
-        btnSave.setEnabled(enabled);
-        btnDelete.setEnabled(enabled);
-        btnBack.setEnabled(enabled);
+        binding.btnSaveInventory.setEnabled(enabled);
+        binding.btnDeleteInventory.setEnabled(enabled);
+        binding.btnInventoryBack.setEnabled(enabled);
     }
-}
+}

android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/PetDetailFragment.java

@@ -4,83 +4,140 @@ import android.os.Bundle;
 
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
-import androidx.appcompat.app.AlertDialog;
-import androidx.core.content.ContextCompat;
 import androidx.fragment.app.Fragment;
+import androidx.lifecycle.ViewModelProvider;
+import androidx.navigation.fragment.NavHostFragment;
 
-import android.util.Log;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
-import android.widget.ArrayAdapter;
-import android.widget.Button;
-import android.widget.EditText;
+import android.widget.AdapterView;
 import android.widget.Spinner;
 import android.widget.TextView;
 import android.widget.Toast;
 
 import com.example.petstoremobile.R;
-import com.example.petstoremobile.api.PetApi;
-import com.example.petstoremobile.api.RetrofitClient;
+import com.example.petstoremobile.databinding.FragmentPetDetailBinding;
+import com.example.petstoremobile.dtos.CustomerDTO;
 import com.example.petstoremobile.dtos.PetDTO;
-import com.example.petstoremobile.fragments.ListFragment;
-import com.example.petstoremobile.fragments.listfragments.PetFragment;
+import com.example.petstoremobile.dtos.StoreDTO;
 import com.example.petstoremobile.utils.ActivityLogger;
+import com.example.petstoremobile.utils.DialogUtils;
 import com.example.petstoremobile.utils.InputValidator;
+import com.example.petstoremobile.utils.Resource;
+import com.example.petstoremobile.utils.SpinnerUtils;
+import com.example.petstoremobile.viewmodels.CustomerViewModel;
+import com.example.petstoremobile.viewmodels.PetViewModel;
+import com.example.petstoremobile.viewmodels.StoreViewModel;
 
-import retrofit2.Call;
-import retrofit2.Callback;
-import retrofit2.Response;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Locale;
 
+import dagger.hilt.android.AndroidEntryPoint;
+
+/**
+ * Fragment for displaying and editing pet details.
+ */
+@AndroidEntryPoint
 public class PetDetailFragment extends Fragment {
 
-    private TextView tvMode, tvPetId;
-    private EditText etPetName, etPetSpecies, etPetBreed, etPetAge, etPetPrice;
-    private Spinner spinnerPetStatus;
-    private Button btnSavePet, btnDeletePet, btnBack;
-    private int petId;
+    private FragmentPetDetailBinding binding;
+    private long petId;
     private boolean isEditing = false;
-    private PetFragment petFragment;
 
-    //set the pet fragment to the parent so we refer back to pet view when save or delete is done
-    public void setPetFragment(PetFragment fragment) {
-        this.petFragment = fragment;
+    private PetViewModel viewModel;
+    private CustomerViewModel customerViewModel;
+    private StoreViewModel storeViewModel;
+    private List<CustomerDTO> customerList = new ArrayList<>();
+    private List<StoreDTO> storeList = new ArrayList<>();
+    private Long selectedCustomerId = null;
+    private Long selectedStoreId = null;
+
+    @Override
+    public void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        viewModel = new ViewModelProvider(this).get(PetViewModel.class);
+        customerViewModel = new ViewModelProvider(this).get(CustomerViewModel.class);
+        storeViewModel = new ViewModelProvider(this).get(StoreViewModel.class);
     }
 
     @Override
-    public View onCreateView(LayoutInflater inflater, ViewGroup container,
+    public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
-        View view = inflater.inflate(R.layout.fragment_pet_detail, container, false);
+        binding = FragmentPetDetailBinding.inflate(inflater, container, false);
+        return binding.getRoot();
+    }
+
+    @Override
+    public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
+        super.onViewCreated(view, savedInstanceState);
 
-        //set up spinner and get controls from layout and display the view depending on the mode
-        initViews(view);
         setupSpinner();
+        loadCustomers();
+        loadStores();
         handleArguments();
 
         //set button click listeners
-        btnBack.setOnClickListener(v -> navigateBack());
-        btnSavePet.setOnClickListener(v -> savePet());
-        btnDeletePet.setOnClickListener(v -> deletePet());
-
-        return view;
+        binding.btnBack.setOnClickListener(v -> navigateBack());
+        binding.btnSavePet.setOnClickListener(v -> savePet());
+        binding.btnDeletePet.setOnClickListener(v -> deletePet());
     }
 
-    //Method to Update or Add a pet
+    @Override
+    public void onDestroyView() {
+        super.onDestroyView();
+        binding = null;
+    }
+
+    /**
+     * Handles the saving of pet data (adding/updating).
+     */
     private void savePet() {
         // Validates all fields using InputValidator
-        if (!InputValidator.isNotEmpty(etPetName, "Pet Name")) return;
-        if (!InputValidator.isNotEmpty(etPetSpecies, "Species")) return;
-        if (!InputValidator.isNotEmpty(etPetBreed, "Breed")) return;
-        if (!InputValidator.isPositiveInteger(etPetAge, "Age")) return;
-        if (!InputValidator.isPositiveDecimal(etPetPrice, "Price")) return;
+        if (!InputValidator.isNotEmpty(binding.etPetName, "Pet Name")) return;
+        if (!InputValidator.isNotEmpty(binding.etPetSpecies, "Species")) return;
+        if (!InputValidator.isNotEmpty(binding.etPetBreed, "Breed")) return;
+        if (!InputValidator.isPositiveInteger(binding.etPetAge, "Age")) return;
+        if (!InputValidator.isPositiveDecimal(binding.etPetPrice, "Price")) return;
 
         //get all the values from the fields
-        String name = etPetName.getText().toString().trim();
-        String species = etPetSpecies.getText().toString().trim();
-        String breed = etPetBreed.getText().toString().trim();
-        int age = Integer.parseInt(etPetAge.getText().toString().trim());
-        String priceStr = etPetPrice.getText().toString().trim();
-        String status = spinnerPetStatus.getSelectedItem().toString();
+        String name = binding.etPetName.getText().toString().trim();
+        String species = binding.etPetSpecies.getText().toString().trim();
+        String breed = binding.etPetBreed.getText().toString().trim();
+        int age = Integer.parseInt(binding.etPetAge.getText().toString().trim());
+        double price = Double.parseDouble(binding.etPetPrice.getText().toString().trim());
+        String status = binding.spinnerPetStatus.getSelectedItem().toString();
+
+        // Get selected customer
+        Long customerId = null;
+        int customerPos = binding.spinnerCustomer.getSelectedItemPosition();
+        if (customerPos > 0) { // 0 means no customer for pet
+            customerId = customerList.get(customerPos - 1).getCustomerId();
+        }
+
+        // Get selected store
+        Long storeId = null;
+        int storePos = binding.spinnerStore.getSelectedItemPosition();
+        if (storePos > 0) {
+            storeId = storeList.get(storePos - 1).getStoreId();
+        }
+
+        // Validation: If status is Available, a store must be selected
+        if ("Available".equalsIgnoreCase(status)) {
+            if (!InputValidator.isSpinnerSelected(binding.spinnerStore, "Store")) return;
+        }
+
+        // Validation: If status is Owned, an owner must be selected
+        if ("Owned".equalsIgnoreCase(status)) {
+            if (!InputValidator.isSpinnerSelected(binding.spinnerCustomer, "Owner")) return;
+        }
+
+        // Validation: If status is Adopted, an owner and store must be selected
+        if ("Adopted".equalsIgnoreCase(status)) {
+            if (!InputValidator.isSpinnerSelected(binding.spinnerCustomer, "Owner")) return;
+            if (!InputValidator.isSpinnerSelected(binding.spinnerStore, "Store")) return;
+        }
 
         //create a pet object to send to the API
         PetDTO petDTO = new PetDTO();
@@ -88,167 +145,221 @@ public class PetDetailFragment extends Fragment {
         petDTO.setPetSpecies(species);
         petDTO.setPetBreed(breed);
         petDTO.setPetAge(age);
-        petDTO.setPetPrice(priceStr);
+        petDTO.setPetPrice(price);
         petDTO.setPetStatus(status);
-
-        PetApi petApi = RetrofitClient.getPetApi(requireContext());
+        petDTO.setCustomerId(customerId);
+        petDTO.setStoreId(storeId);
 
         //check if the pet is being edited or added
         if (isEditing) {
             // Update existing pet
-            petDTO.setPetId((long) petId);
-            petApi.updatePet((long) petId, petDTO).enqueue(new Callback<PetDTO>() {
-                @Override
-                public void onResponse(Call<PetDTO> call, Response<PetDTO> response) {
-                    if (response.isSuccessful()) {
-                        ActivityLogger.logChange(requireContext(), "Pet", "UPDATED", petId);
-                        Toast.makeText(getContext(), "Pet updated successfully!", Toast.LENGTH_SHORT).show();
-                        navigateBack();
-                    } else {
-                        Toast.makeText(getContext(), "Failed to update pet: " + response.code(), Toast.LENGTH_SHORT).show();
-                    }
-                }
-
-                @Override
-                public void onFailure(Call<PetDTO> call, Throwable t) {
-                    ActivityLogger.logException(requireContext(), "PetDetailFragment.updatePet", new Exception(t));
-                    Log.e("PetDetailFragment", "Error updating pet", t);
-                    Toast.makeText(getContext(), "Error: " + t.getMessage(), Toast.LENGTH_SHORT).show();
+            petDTO.setPetId(petId);
+            viewModel.updatePet(petId, petDTO).observe(getViewLifecycleOwner(), resource -> {
+                if (resource.status == Resource.Status.SUCCESS) {
+                    ActivityLogger.logChange(requireContext(), "Pet", "UPDATED", (int) petId);
+                    Toast.makeText(getContext(), "Pet updated successfully!", Toast.LENGTH_SHORT).show();
+                    navigateToPetList();
+                } else if (resource.status == Resource.Status.ERROR) {
+                    Toast.makeText(getContext(), "Error: " + resource.message, Toast.LENGTH_SHORT).show();
                 }
             });
         } else {
             // Add new pet
-            petApi.createPet(petDTO).enqueue(new Callback<PetDTO>() {
-                @Override
-                public void onResponse(Call<PetDTO> call, Response<PetDTO> response) {
-                    if (response.isSuccessful()) {
-                        ActivityLogger.log(requireContext(), "Added new Pet: " + name);
-                        Toast.makeText(getContext(), "Pet added successfully!", Toast.LENGTH_SHORT).show();
-                        navigateBack();
-                    } else {
-                        Toast.makeText(getContext(), "Failed to add pet: " + response.code(), Toast.LENGTH_SHORT).show();
-                    }
-                }
-
-                @Override
-                public void onFailure(Call<PetDTO> call, Throwable t) {
-                    ActivityLogger.logException(requireContext(), "PetDetailFragment.createPet", new Exception(t));
-                    Log.e("PetDetailFragment", "Error adding pet", t);
-                    Toast.makeText(getContext(), "Error: " + t.getMessage(), Toast.LENGTH_SHORT).show();
+            viewModel.createPet(petDTO).observe(getViewLifecycleOwner(), resource -> {
+                if (resource.status == Resource.Status.SUCCESS) {
+                    ActivityLogger.log(requireContext(), "Added new Pet: " + name);
+                    Toast.makeText(getContext(), "Pet added successfully!", Toast.LENGTH_SHORT).show();
+                    navigateToPetList();
+                } else if (resource.status == Resource.Status.ERROR) {
+                    Toast.makeText(getContext(), "Error: " + resource.message, Toast.LENGTH_SHORT).show();
                 }
             });
         }
     }
 
-    //Method to Delete a pet
+    /**
+     * Displays a confirmation dialog and handles the deletion of a pet.
+     */
     private void deletePet() {
-        //Alert the user to confirm the delete
-        new AlertDialog.Builder(requireContext())
-                .setTitle("Delete Pet")
-                .setMessage("Are you sure you want to delete " + etPetName.getText().toString() + "?")
-                .setPositiveButton("Delete", (dialog, which) -> {
-                    PetApi petApi = RetrofitClient.getPetApi(requireContext());
-                    //if they say yes then delete the pet
-                    petApi.deletePet((long) petId).enqueue(new Callback<Void>() {
-                        @Override
-                        public void onResponse(Call<Void> call, Response<Void> response) {
-                            if (response.isSuccessful()) {
-                                ActivityLogger.logChange(requireContext(), "Pet", "DELETED", petId);
-                                Toast.makeText(getContext(), "Pet deleted successfully!", Toast.LENGTH_SHORT).show();
-                                navigateBack();
-                            } else {
-                                Toast.makeText(getContext(), "Failed to delete pet: " + response.code(), Toast.LENGTH_SHORT).show();
-                            }
-                        }
-
-                        @Override
-                        public void onFailure(Call<Void> call, Throwable t) {
-                            ActivityLogger.logException(requireContext(), "PetDetailFragment.deletePet", new Exception(t));
-                            Log.e("PetDetailFragment", "Error deleting pet", t);
-                            Toast.makeText(getContext(), "Error: " + t.getMessage(), Toast.LENGTH_SHORT).show();
-                        }
-                    });
-                })
-                .setNegativeButton("Cancel", null)
-                .show();
+        DialogUtils.showDeleteConfirmDialog(requireContext(), "Pet", () -> 
+                viewModel.deletePet(petId).observe(getViewLifecycleOwner(), resource -> {
+                    if (resource.status == Resource.Status.SUCCESS) {
+                        ActivityLogger.logChange(requireContext(), "Pet", "DELETED", (int) petId);
+                        Toast.makeText(getContext(), "Pet deleted successfully!", Toast.LENGTH_SHORT).show();
+                        navigateToPetList();
+                    } else if (resource.status == Resource.Status.ERROR) {
+                        Toast.makeText(getContext(), "Delete failed: " + resource.message, Toast.LENGTH_SHORT).show();
+                    }
+                }));
     }
 
-    //Helper method to navigate back to the list
+    /**
+     * Navigates back to the pet list screen.
+     */
+    private void navigateToPetList() {
+        NavHostFragment.findNavController(this).popBackStack(R.id.nav_pet, false);
+    }
+
+    /**
+     * Navigates back to the previous screen.
+     */
     private void navigateBack() {
-        ListFragment listFragment = (ListFragment) getParentFragment();
-        if (listFragment != null) {
-            // If editing pop back twice to get back to PetDetail Fragment instead of PetProfileFragment
-            if (isEditing) {
-                listFragment.getChildFragmentManager().popBackStack();
-            }
-            listFragment.getChildFragmentManager().popBackStack();
-        }
+        NavHostFragment.findNavController(this).popBackStack();
     }
 
-    //helper function to check if pet is being edited or added and show the view accordingly
+    /**
+     * Handles arguments passed to the fragment to determine if it's in edit or add mode.
+     */
     private void handleArguments() {
         // Pet is being edited if the bundle contains a petId
         if (getArguments() != null && getArguments().containsKey("petId")) {
             // Get pet data from arguments and populate fields
             isEditing = true;
-            petId = getArguments().getInt("petId");
-            tvMode.setText("Edit Pet");
-            tvPetId.setText("ID: " + petId);
-            etPetName.setText(getArguments().getString("petName"));
-            etPetSpecies.setText(getArguments().getString("petSpecies"));
-            etPetBreed.setText(getArguments().getString("petBreed"));
-            etPetAge.setText(String.valueOf(getArguments().getInt("petAge")));
-            etPetPrice.setText(String.valueOf(getArguments().getDouble("petPrice")));
-            String status = getArguments().getString("petStatus");
-            if ("Available".equals(status)) {
-                spinnerPetStatus.setSelection(0);
-            } else {
-                spinnerPetStatus.setSelection(1);
-            }
-            btnDeletePet.setVisibility(View.VISIBLE);
+            petId = getArguments().getLong("petId");
+            binding.tvMode.setText("Edit Pet");
+            binding.tvPetId.setText("ID: " + petId);
+            binding.tvPetId.setVisibility(View.VISIBLE);
+            binding.btnDeletePet.setVisibility(View.VISIBLE);
+            loadPetData();
         } else {
             // Pet is being added
             // Set default values for add a new pet
             isEditing = false;
-            tvMode.setText("Add Pet");
-            tvPetId.setVisibility(View.GONE);
-            btnDeletePet.setVisibility(View.GONE);
-            btnSavePet.setText("Add");
+            binding.tvMode.setText("Add Pet");
+            binding.tvPetId.setVisibility(View.GONE);
+            binding.btnDeletePet.setVisibility(View.GONE);
+            binding.btnSavePet.setText("Add");
         }
     }
 
-    //helper function to get controls from layout
-    private void initViews(View view) {
-        tvMode = view.findViewById(R.id.tvMode);
-        tvPetId = view.findViewById(R.id.tvPetId);
-        etPetName = view.findViewById(R.id.etPetName);
-        etPetSpecies = view.findViewById(R.id.etPetSpecies);
-        etPetBreed = view.findViewById(R.id.etPetBreed);
-        etPetAge = view.findViewById(R.id.etPetAge);
-        etPetPrice = view.findViewById(R.id.etPetPrice);
-        spinnerPetStatus = view.findViewById(R.id.spinnerPetStatus);
-        btnSavePet = view.findViewById(R.id.btnSavePet);
-        btnDeletePet = view.findViewById(R.id.btnDeletePet);
-        btnBack = view.findViewById(R.id.btnBack);
-    }
+    /**
+     * Fetches specific pet details from the backend using the ID.
+     */
+    private void loadPetData() {
+        viewModel.getPetById(petId).observe(getViewLifecycleOwner(), resource -> {
+            if (resource == null) return;
+            if (resource.status == Resource.Status.SUCCESS && resource.data != null) {
+                PetDTO p = resource.data;
+                binding.etPetName.setText(p.getPetName());
+                binding.etPetSpecies.setText(p.getPetSpecies());
+                binding.etPetBreed.setText(p.getPetBreed());
+                binding.etPetAge.setText(String.valueOf(p.getPetAge()));
+                if (p.getPetPrice() != null) {
+                    binding.etPetPrice.setText(String.format(Locale.getDefault(), "%.2f", p.getPetPrice()));
+                }
+                SpinnerUtils.setSelectionByValue(binding.spinnerPetStatus, p.getPetStatus());
+                
+                selectedCustomerId = p.getCustomerId();
+                updateCustomerSpinnerSelection();
 
-    //helper function to set up the spinner menu for pet status
-    private void setupSpinner() {
-        ArrayAdapter<String> adapter = new ArrayAdapter<String>(requireContext(),
-                android.R.layout.simple_spinner_item,
-                new String[]{"Available", "Adopted"}) {
-
-            //Override the getView method for the spinner to make the text color darker for more readability
-            @NonNull
-            @Override
-            public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {
-                View view = super.getView(position, convertView, parent);
-                ((TextView) view).setTextColor(ContextCompat.getColor(requireContext(), R.color.text_dark));
-                return view;
+                selectedStoreId = p.getStoreId();
+                updateStoreSpinnerSelection();
+            } else if (resource.status == Resource.Status.ERROR) {
+                Toast.makeText(getContext(), "Failed to load pet: " + resource.message, Toast.LENGTH_SHORT).show();
             }
-        };
-        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
-        spinnerPetStatus.setAdapter(adapter);
+        });
     }
 
+    /**
+     * Fetches the list of customers and populates the spinner.
+     */
+    private void loadCustomers() {
+        customerViewModel.getAllCustomers(0, 1000).observe(getViewLifecycleOwner(), resource -> {
+            if (resource != null && resource.status == Resource.Status.SUCCESS && resource.data != null) {
+                customerList = resource.data.getContent();
+                updateCustomerSpinnerSelection();
+            }
+        });
+    }
+
+    /**
+     * Fetches the list of stores and populates the spinner.
+     */
+    private void loadStores() {
+        storeViewModel.getAllStores(0, 1000).observe(getViewLifecycleOwner(), resource -> {
+            if (resource != null && resource.status == Resource.Status.SUCCESS && resource.data != null) {
+                storeList = resource.data.getContent();
+                updateStoreSpinnerSelection();
+            }
+        });
+    }
+
+    /**
+     * Updates the customer spinner with the current list and sets the selection if needed.
+     */
+    private void updateCustomerSpinnerSelection() {
+        SpinnerUtils.populateSpinner(
+                requireContext(),
+                binding.spinnerCustomer,
+                customerList,
+                CustomerDTO::getFullName,
+                "No Owner",
+                selectedCustomerId,
+                CustomerDTO::getCustomerId
+        );
+    }
+
+    /**
+     * Updates the store spinner with the current list and sets the selection if needed.
+     */
+    private void updateStoreSpinnerSelection() {
+        SpinnerUtils.populateSpinner(
+                requireContext(),
+                binding.spinnerStore,
+                storeList,
+                StoreDTO::getStoreName,
+                "None",
+                selectedStoreId,
+                StoreDTO::getStoreId
+        );
+    }
+
+    /**
+     * Initializes the spinner for pet status selection.
+     */
+    private void setupSpinner() {
+        SpinnerUtils.setupStringSpinner(requireContext(), binding.spinnerPetStatus,
+                new String[]{"Available", "Adopted", "Owned"});
+
+        binding.spinnerPetStatus.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
+            @Override
+            public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
+                String status = parent.getItemAtPosition(position).toString();
+
+                // Clear any existing error icons when status changes
+                clearSpinnerError(binding.spinnerCustomer);
+                clearSpinnerError(binding.spinnerStore);
+
+                //Disable the customer spinner if the status is "Available"
+                if ("Available".equalsIgnoreCase(status)) {
+                    binding.spinnerCustomer.setSelection(0);
+                    binding.spinnerCustomer.setEnabled(false);
+                } else {
+                    binding.spinnerCustomer.setEnabled(true);
+                }
+
+                //Disable the store spinner if the status is "Owned"
+                if ("Owned".equalsIgnoreCase(status)) {
+                    binding.spinnerStore.setSelection(0);
+                    binding.spinnerStore.setEnabled(false);
+                } else {
+                    binding.spinnerStore.setEnabled(true);
+                }
+            }
+
+            @Override
+            public void onNothingSelected(AdapterView<?> parent) {
+            }
+        });
+    }
+
+    /**
+     * Clears error messages from a Spinner's selected view.
+     */
+    private void clearSpinnerError(Spinner spinner) {
+        View selectedView = spinner.getSelectedView();
+        if (selectedView instanceof TextView) {
+            ((TextView) selectedView).setError(null);
+        }
+    }
 }

android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/ProductDetailFragment.java

@@ -1,190 +1,321 @@
 package com.example.petstoremobile.fragments.listfragments.detailfragments;
 
+import android.net.Uri;
 import android.os.Bundle;
-import android.util.Log;
 import android.view.*;
 import android.widget.*;
 import androidx.annotation.NonNull;
-import androidx.appcompat.app.AlertDialog;
+import androidx.annotation.Nullable;
 import androidx.fragment.app.Fragment;
+import androidx.lifecycle.ViewModelProvider;
+import androidx.navigation.fragment.NavHostFragment;
+
+import com.bumptech.glide.Glide;
 import com.example.petstoremobile.R;
 import com.example.petstoremobile.api.*;
+import com.example.petstoremobile.api.auth.TokenManager;
+import com.example.petstoremobile.databinding.FragmentProductDetailBinding;
 import com.example.petstoremobile.dtos.*;
-import com.example.petstoremobile.fragments.ListFragment;
+import com.example.petstoremobile.viewmodels.ProductViewModel;
+import com.example.petstoremobile.utils.DialogUtils;
+import com.example.petstoremobile.utils.FileUtils;
+import com.example.petstoremobile.utils.GlideUtils;
+import com.example.petstoremobile.utils.ImagePickerHelper;
+import com.example.petstoremobile.utils.InputValidator;
+import com.example.petstoremobile.utils.Resource;
+import com.example.petstoremobile.utils.SpinnerUtils;
+
+import java.io.File;
 import java.math.BigDecimal;
 import java.util.*;
-import retrofit2.*;
 
+import javax.inject.Inject;
+
+import javax.inject.Named;
+
+import dagger.hilt.android.AndroidEntryPoint;
+import okhttp3.MediaType;
+import okhttp3.MultipartBody;
+import okhttp3.RequestBody;
+
+/**
+ * Fragment for displaying and editing product details, including image selection.
+ */
+@AndroidEntryPoint
 public class ProductDetailFragment extends Fragment {
 
-    private TextView tvMode, tvProductId;
-    private EditText etProductName, etProductDesc, etProductPrice;
-    private Spinner spinnerCategory;
-    private Button btnSave, btnDelete, btnBack;
+    private FragmentProductDetailBinding binding;
 
     private long prodId = -1;
     private boolean isEditing = false;
     private long preselectedCategoryId = -1;
+    private boolean hasImage = false;
+    private boolean isImageChanged = false;
+    private boolean isImageRemoved = false;
 
     private List<CategoryDTO> categoryList = new ArrayList<>();
+    private Uri photoUri;
+    private ProductViewModel viewModel;
+    private ImagePickerHelper imagePickerHelper;
 
+    @Inject @Named("baseUrl") String baseUrl;
+    @Inject TokenManager tokenManager;
+
+    /**
+     * Initializes activity launchers and the ImagePickerHelper.
+     */
+    @Override
+    public void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        viewModel = new ViewModelProvider(this).get(ProductViewModel.class);
+
+        imagePickerHelper = new ImagePickerHelper(this, "product_photo.jpg", new ImagePickerHelper.ImagePickerListener() {
+            @Override
+            public void onImagePicked(Uri uri) {
+                photoUri = uri;
+                Glide.with(ProductDetailFragment.this).load(uri).into(binding.ivProductImage);
+                hasImage = true;
+                isImageChanged = true;
+                isImageRemoved = false;
+            }
+
+            @Override
+            public void onImageRemoved() {
+                photoUri = null;
+                hasImage = false;
+                isImageChanged = false;
+                isImageRemoved = true;
+                binding.ivProductImage.setImageResource(R.drawable.placeholder2);
+            }
+        });
+    }
+
+    /**
+     * Inflates the layout.
+     */
     @Override
     public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
-        View view = inflater.inflate(R.layout.fragment_product_detail, container, false);
-        initViews(view);
+        binding = FragmentProductDetailBinding.inflate(inflater, container, false);
+        return binding.getRoot();
+    }
+
+    /**
+     * Sets up UI components and listeners after the view is created.
+     */
+    @Override
+    public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
+        super.onViewCreated(view, savedInstanceState);
+
         loadCategories();
         handleArguments();
 
-        btnBack.setOnClickListener(v -> navigateBack());
-        btnSave.setOnClickListener(v -> saveProduct());
-        btnDelete.setOnClickListener(v -> confirmDelete());
-        return view;
+        binding.btnProductBack.setOnClickListener(v -> navigateBack());
+        binding.btnSaveProduct.setOnClickListener(v -> saveProduct());
+        binding.btnDeleteProduct.setOnClickListener(v -> confirmDelete());
+        binding.ivProductImage.setOnClickListener(v -> imagePickerHelper.showImagePickerDialog("Select Product Image", hasImage));
     }
 
-    private void initViews(View v) {
-        tvMode          = v.findViewById(R.id.tvProductMode);
-        tvProductId     = v.findViewById(R.id.tvProductId);
-        etProductName   = v.findViewById(R.id.etProductName);
-        etProductDesc   = v.findViewById(R.id.etProductDesc);
-        etProductPrice  = v.findViewById(R.id.etProductPrice);
-        spinnerCategory = v.findViewById(R.id.spinnerProductCategory);
-        btnSave         = v.findViewById(R.id.btnSaveProduct);
-        btnDelete       = v.findViewById(R.id.btnDeleteProduct);
-        btnBack         = v.findViewById(R.id.btnProductBack);
+    @Override
+    public void onDestroyView() {
+        super.onDestroyView();
+        binding = null;
     }
 
+    /**
+     * Fetches all product categories for the selection spinner.
+     */
     private void loadCategories() {
-        RetrofitClient.getCategoryApi(requireContext()).getAllCategories(0, 100)
-                .enqueue(new Callback<PageResponse<CategoryDTO>>() {
-                    public void onResponse(Call<PageResponse<CategoryDTO>> c,
-                                           Response<PageResponse<CategoryDTO>> r) {
-                        if (r.isSuccessful() && r.body() != null) {
-                            categoryList = r.body().getContent();
-                            populateCategorySpinner();
-                        }
-                    }
-                    public void onFailure(Call<PageResponse<CategoryDTO>> c, Throwable t) {
-                        Log.e("ProductDetail", "Category load failed: " + t.getMessage());
-                    }
-                });
-    }
-
-    private void populateCategorySpinner() {
-        List<String> names = new ArrayList<>();
-        names.add("-- Select Category --");
-        for (CategoryDTO c : categoryList) names.add(c.getCategoryName());
-        spinnerCategory.setAdapter(new ArrayAdapter<>(requireContext(),
-                android.R.layout.simple_spinner_item, names));
-        if (preselectedCategoryId != -1) {
-            for (int i = 0; i < categoryList.size(); i++) {
-                if (categoryList.get(i).getCategoryId().equals(preselectedCategoryId)) {
-                    spinnerCategory.setSelection(i + 1); break;
-                }
+        viewModel.getAllCategories(0, 100).observe(getViewLifecycleOwner(), resource -> {
+            if (resource != null && resource.status == Resource.Status.SUCCESS && resource.data != null) {
+                categoryList = resource.data.getContent();
+                SpinnerUtils.populateSpinner(requireContext(), binding.spinnerProductCategory, categoryList,
+                        CategoryDTO::getCategoryName, "-- Select Category --",
+                        preselectedCategoryId, CategoryDTO::getCategoryId);
             }
-        }
+        });
     }
 
+    /**
+     * Checks if the fragment was opened with existing product data for editing.
+     */
     private void handleArguments() {
         Bundle a = getArguments();
         if (a != null && a.containsKey("prodId")) {
             isEditing = true;
             prodId = a.getLong("prodId");
-            preselectedCategoryId = a.getLong("categoryId", -1);
-
-            tvMode.setText("Edit Product");
-            tvProductId.setText("ID: " + prodId);
-            tvProductId.setVisibility(View.VISIBLE);
-            etProductName.setText(a.getString("prodName"));
-            etProductDesc.setText(a.getString("prodDesc"));
-            etProductPrice.setText(a.getString("prodPrice"));
-            btnDelete.setVisibility(View.VISIBLE);
+            binding.tvProductMode.setText("Edit Product");
+            binding.tvProductId.setText("ID: " + prodId);
+            binding.tvProductId.setVisibility(View.VISIBLE);
+            binding.btnDeleteProduct.setVisibility(View.VISIBLE);
+            loadProductData();
+            loadProductImage();
         } else {
-            tvMode.setText("Add Product");
-            btnDelete.setVisibility(View.GONE);
-            tvProductId.setVisibility(View.GONE);
+            binding.tvProductMode.setText("Add Product");
+            binding.btnDeleteProduct.setVisibility(View.GONE);
+            binding.tvProductId.setVisibility(View.GONE);
+            hasImage = false;
         }
     }
 
-    private void saveProduct() {
-        String name = etProductName.getText().toString().trim();
-        String desc = etProductDesc.getText().toString().trim();
-        String priceStr = etProductPrice.getText().toString().trim();
+    /**
+     * Loads the product data from the backend.
+     */
+    private void loadProductData() {
+        viewModel.getProductById(prodId).observe(getViewLifecycleOwner(), resource -> {
+            if (resource == null) return;
+            if (resource.status == Resource.Status.SUCCESS && resource.data != null) {
+                ProductDTO p = resource.data;
+                binding.etProductName.setText(p.getProdName());
+                binding.etProductDesc.setText(p.getProdDesc());
+                binding.etProductPrice.setText(p.getProdPrice() != null ? p.getProdPrice().toString() : "");
+                preselectedCategoryId = p.getCategoryId() != null ? p.getCategoryId() : -1;
+                
+                // Refresh spinner selection once data is loaded
+                if (!categoryList.isEmpty()) {
+                    SpinnerUtils.populateSpinner(requireContext(), binding.spinnerProductCategory, categoryList,
+                            CategoryDTO::getCategoryName, "-- Select Category --",
+                            preselectedCategoryId, CategoryDTO::getCategoryId);
+                }
+            } else if (resource.status == Resource.Status.ERROR) {
+                Toast.makeText(getContext(), "Failed to load product: " + resource.message, Toast.LENGTH_SHORT).show();
+            }
+        });
+    }
 
-        if (name.isEmpty()) {
-            etProductName.setError("Enter product name"); return;
+    /**
+     * Loads the product image from the backend.
+     */
+    private void loadProductImage() {
+        String imageUrl = baseUrl + String.format(Locale.US, ProductApi.PRODUCT_IMAGE_PATH, prodId);
+        String token = tokenManager.getToken();
+
+        GlideUtils.loadImageWithToken(requireContext(), binding.ivProductImage, imageUrl, token, R.drawable.placeholder2, new GlideUtils.ImageLoadListener() {
+            @Override
+            public void onResourceReady() {
+                hasImage = true;
+            }
+
+            @Override
+            public void onLoadFailed() {
+                hasImage = false;
+            }
+        });
+    }
+
+    /**
+     * Performs image related actions (upload/delete) after product details are saved.
+     */
+    private void performPendingImageActions(String successMsg) {
+        if (isImageRemoved) {
+            viewModel.deleteProductImage(prodId).observe(getViewLifecycleOwner(), resource -> {
+                if (resource != null && resource.status != Resource.Status.LOADING) {
+                    if (resource.status == Resource.Status.SUCCESS) {
+                        Toast.makeText(getContext(), successMsg, Toast.LENGTH_SHORT).show();
+                    } else {
+                        Toast.makeText(getContext(), successMsg + " (but image removal failed)", Toast.LENGTH_SHORT).show();
+                    }
+                    navigateBack();
+                }
+            });
+        } else if (isImageChanged && photoUri != null) {
+            uploadProductImageAndNavigate(photoUri, successMsg);
+        } else {
+            Toast.makeText(getContext(), successMsg, Toast.LENGTH_SHORT).show();
+            navigateBack();
         }
-        if (spinnerCategory.getSelectedItemPosition() == 0) {
+    }
+
+    /**
+     * Uploads the selected image file to the server.
+     */
+    private void uploadProductImageAndNavigate(Uri uri, String successMsg) {
+        File file = FileUtils.getFileFromUri(requireContext(), uri);
+        if (file == null) {
+            Toast.makeText(getContext(), successMsg, Toast.LENGTH_SHORT).show();
+            navigateBack();
+            return;
+        }
+
+        RequestBody requestFile = RequestBody.create(file, MediaType.parse(requireContext().getContentResolver().getType(uri)));
+        MultipartBody.Part body = MultipartBody.Part.createFormData("image", file.getName(), requestFile);
+
+        viewModel.uploadProductImage(prodId, body).observe(getViewLifecycleOwner(), resource -> {
+            if (resource != null && resource.status != Resource.Status.LOADING) {
+                if (resource.status == Resource.Status.SUCCESS) {
+                    Toast.makeText(getContext(), successMsg, Toast.LENGTH_SHORT).show();
+                } else {
+                    Toast.makeText(getContext(), successMsg + " (but image upload failed)", Toast.LENGTH_SHORT).show();
+                }
+                navigateBack();
+            }
+        });
+    }
+
+    /**
+     * Validates input fields and saves product information to the backend.
+     */
+    private void saveProduct() {
+        if (!InputValidator.isNotEmpty(binding.etProductName, "Product Name")) return;
+
+        if (binding.spinnerProductCategory.getSelectedItemPosition() == 0) {
             Toast.makeText(getContext(), "Select a category", Toast.LENGTH_SHORT).show(); return;
         }
-        if (priceStr.isEmpty()) {
-            etProductPrice.setError("Enter price"); return;
+
+        if (!InputValidator.isNotEmpty(binding.etProductPrice, "Price") ||
+            !InputValidator.isPositiveDecimal(binding.etProductPrice, "Price")) {
+            return;
         }
 
-        CategoryDTO category = categoryList.get(spinnerCategory.getSelectedItemPosition() - 1);
-        BigDecimal price;
-        try {
-            price = new BigDecimal(priceStr);
-        } catch (Exception e) {
-            etProductPrice.setError("Invalid price"); return;
-        }
+        String name = binding.etProductName.getText().toString().trim();
+        String desc = binding.etProductDesc.getText().toString().trim();
+        BigDecimal price = new BigDecimal(binding.etProductPrice.getText().toString().trim());
 
+        CategoryDTO category = categoryList.get(binding.spinnerProductCategory.getSelectedItemPosition() - 1);
         ProductDTO dto = new ProductDTO(name, category.getCategoryId(), desc, price);
 
-        Log.d("PRODUCT_SAVE", "name=" + name + " categoryId=" + category.getCategoryId()
-                + " price=" + price);
-
-        ProductApi api = RetrofitClient.getProductApi(requireContext());
         if (isEditing) {
-            api.updateProduct(prodId, dto).enqueue(simpleCallback("Updated"));
+            viewModel.updateProduct(prodId, dto).observe(getViewLifecycleOwner(), resource -> {
+                if (resource != null && resource.status != Resource.Status.LOADING) {
+                    if (resource.status == Resource.Status.SUCCESS) {
+                        performPendingImageActions("Updated");
+                    } else {
+                        Toast.makeText(getContext(), "Error: " + resource.message, Toast.LENGTH_SHORT).show();
+                    }
+                }
+            });
         } else {
-            api.createProduct(dto).enqueue(simpleCallback("Saved"));
+            viewModel.createProduct(dto).observe(getViewLifecycleOwner(), resource -> {
+                if (resource != null && resource.status != Resource.Status.LOADING) {
+                    if (resource.status == Resource.Status.SUCCESS && resource.data != null) {
+                        prodId = resource.data.getProdId();
+                        performPendingImageActions("Saved");
+                    } else {
+                        Toast.makeText(getContext(), "Error saving: " + resource.message, Toast.LENGTH_SHORT).show();
+                    }
+                }
+            });
         }
     }
 
-    private Callback<ProductDTO> simpleCallback(String msg) {
-        return new Callback<>() {
-            public void onResponse(Call<ProductDTO> c, Response<ProductDTO> r) {
-                if (r.isSuccessful()) {
-                    Toast.makeText(getContext(), msg, Toast.LENGTH_SHORT).show();
-                    navigateBack();
-                } else {
-                    try {
-                        String err = r.errorBody().string();
-                        Log.e("PRODUCT_SAVE", "Error: " + err);
-                        Toast.makeText(getContext(), "Error " + r.code(), Toast.LENGTH_SHORT).show();
-                    } catch (Exception e) {
-                        Log.e("PRODUCT_SAVE", "Failed to read error");
-                    }
-                }
-            }
-            public void onFailure(Call<ProductDTO> c, Throwable t) {
-                Log.e("PRODUCT_SAVE", "Failure: " + t.getMessage());
-                Toast.makeText(getContext(), "Network error", Toast.LENGTH_SHORT).show();
-            }
-        };
-    }
-
+    /**
+     * Displays a confirmation dialog before deleting the product.
+     */
     private void confirmDelete() {
-        new AlertDialog.Builder(requireContext())
-                .setTitle("Delete Product?")
-                .setPositiveButton("Yes", (d, w) ->
-                        RetrofitClient.getProductApi(requireContext())
-                                .deleteProduct(prodId)
-                                .enqueue(new Callback<Void>() {
-                                    public void onResponse(Call<Void> c, Response<Void> r) {
-                                        navigateBack();
-                                    }
-                                    public void onFailure(Call<Void> c, Throwable t) {
-                                        Toast.makeText(getContext(), "Delete failed",
-                                                Toast.LENGTH_SHORT).show();
-                                    }
-                                }))
-                .setNegativeButton("No", null).show();
+        DialogUtils.showDeleteConfirmDialog(requireContext(), "Product", () -> 
+                viewModel.deleteProduct(prodId).observe(getViewLifecycleOwner(), resource -> {
+                    if (resource != null && resource.status == Resource.Status.SUCCESS) {
+                        navigateBack();
+                    } else if (resource != null && resource.status == Resource.Status.ERROR) {
+                        Toast.makeText(getContext(), "Delete failed: " + resource.message, Toast.LENGTH_SHORT).show();
+                    }
+                }));
     }
 
+    /**
+     * Navigates back to the previous fragment.
+     */
     private void navigateBack() {
-        ListFragment lf = (ListFragment) getParentFragment();
-        if (lf != null) lf.getChildFragmentManager().popBackStack();
+        NavHostFragment.findNavController(this).popBackStack();
     }
-}
+}

android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/ProductSupplierDetailFragment.java

@@ -1,26 +1,36 @@
 package com.example.petstoremobile.fragments.listfragments.detailfragments;
 
 import android.os.Bundle;
-import android.util.Log;
 import android.view.*;
 import android.widget.*;
 import androidx.annotation.NonNull;
-import androidx.appcompat.app.AlertDialog;
+import androidx.annotation.Nullable;
 import androidx.fragment.app.Fragment;
-import com.example.petstoremobile.R;
-import com.example.petstoremobile.api.*;
+import androidx.lifecycle.ViewModelProvider;
+import androidx.navigation.fragment.NavHostFragment;
+
+import com.example.petstoremobile.databinding.FragmentProductSupplierDetailBinding;
 import com.example.petstoremobile.dtos.*;
-import com.example.petstoremobile.fragments.ListFragment;
+import com.example.petstoremobile.utils.DialogUtils;
+import com.example.petstoremobile.utils.InputValidator;
+import com.example.petstoremobile.utils.Resource;
+import com.example.petstoremobile.utils.SpinnerUtils;
+import com.example.petstoremobile.viewmodels.ProductSupplierViewModel;
+import com.example.petstoremobile.viewmodels.ProductViewModel;
+import com.example.petstoremobile.viewmodels.SupplierViewModel;
+
 import java.math.BigDecimal;
 import java.util.*;
-import retrofit2.*;
 
+import dagger.hilt.android.AndroidEntryPoint;
+
+/**
+ * Fragment for displaying and editing the relationship between products and suppliers.
+ */
+@AndroidEntryPoint
 public class ProductSupplierDetailFragment extends Fragment {
 
-    private TextView tvMode;
-    private Spinner spinnerProduct, spinnerSupplier;
-    private EditText etCost;
-    private Button btnSave, btnDelete, btnBack;
+    private FragmentProductSupplierDetailBinding binding;
 
     private boolean isEditing = false;
     private long editProductId = -1;
@@ -31,190 +41,171 @@ public class ProductSupplierDetailFragment extends Fragment {
     private List<ProductDTO> productList = new ArrayList<>();
     private List<SupplierDTO> supplierList = new ArrayList<>();
 
+    private ProductSupplierViewModel psViewModel;
+    private ProductViewModel productViewModel;
+    private SupplierViewModel supplierViewModel;
+
+    @Override
+    public void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        psViewModel = new ViewModelProvider(this).get(ProductSupplierViewModel.class);
+        productViewModel = new ViewModelProvider(this).get(ProductViewModel.class);
+        supplierViewModel = new ViewModelProvider(this).get(SupplierViewModel.class);
+    }
+
     @Override
     public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
-        View view = inflater.inflate(R.layout.fragment_product_supplier_detail, container, false);
-        initViews(view);
-        loadData();
+        binding = FragmentProductSupplierDetailBinding.inflate(inflater, container, false);
+        return binding.getRoot();
+    }
+
+    @Override
+    public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
+        super.onViewCreated(view, savedInstanceState);
+        loadSpinnersData();
         handleArguments();
 
-        btnBack.setOnClickListener(v -> navigateBack());
-        btnSave.setOnClickListener(v -> save());
-        btnDelete.setOnClickListener(v -> confirmDelete());
-        return view;
+        binding.btnPSBack.setOnClickListener(v -> navigateBack());
+        binding.btnSavePS.setOnClickListener(v -> save());
+        binding.btnDeletePS.setOnClickListener(v -> confirmDelete());
     }
 
-    private void initViews(View v) {
-        tvMode          = v.findViewById(R.id.tvPSMode);
-        spinnerProduct  = v.findViewById(R.id.spinnerPSProduct);
-        spinnerSupplier = v.findViewById(R.id.spinnerPSSupplier);
-        etCost          = v.findViewById(R.id.etPSCost);
-        btnSave         = v.findViewById(R.id.btnSavePS);
-        btnDelete       = v.findViewById(R.id.btnDeletePS);
-        btnBack         = v.findViewById(R.id.btnPSBack);
+    @Override
+    public void onDestroyView() {
+        super.onDestroyView();
+        binding = null;
     }
 
-    private void loadData() {
+    /**
+     * Fetches products and suppliers to populate the spinners.
+     */
+    private void loadSpinnersData() {
         loadProducts();
         loadSuppliers();
     }
 
+    /**
+     * Loads the list of products from the API.
+     */
     private void loadProducts() {
-        RetrofitClient.getProductApi(requireContext()).getAllProducts(null, 0, 200)
-                .enqueue(new Callback<PageResponse<ProductDTO>>() {
-                    public void onResponse(Call<PageResponse<ProductDTO>> c,
-                                           Response<PageResponse<ProductDTO>> r) {
-                        if (r.isSuccessful() && r.body() != null) {
-                            productList = r.body().getContent();
-                            populateProductSpinner();
-                        }
-                    }
-                    public void onFailure(Call<PageResponse<ProductDTO>> c, Throwable t) {
-                        Log.e("PSDetail", "Product load failed: " + t.getMessage());
-                    }
-                });
-    }
-
-    private void populateProductSpinner() {
-        List<String> names = new ArrayList<>();
-        names.add("-- Select Product --");
-        for (ProductDTO p : productList) names.add(p.getProdName());
-        spinnerProduct.setAdapter(new ArrayAdapter<>(requireContext(),
-                android.R.layout.simple_spinner_item, names));
-        if (preselectedProductId != -1) {
-            for (int i = 0; i < productList.size(); i++) {
-                if (productList.get(i).getProdId().equals(preselectedProductId)) {
-                    spinnerProduct.setSelection(i + 1); break;
-                }
+        productViewModel.getAllProducts(null, null, 0, 200, "prodName").observe(getViewLifecycleOwner(), resource -> {
+            if (resource.status == Resource.Status.SUCCESS && resource.data != null) {
+                productList = resource.data.getContent();
+                refreshProductSpinner();
             }
-        }
+        });
     }
 
+    private void refreshProductSpinner() {
+        SpinnerUtils.populateSpinner(requireContext(), binding.spinnerPSProduct, productList,
+                ProductDTO::getProdName, "-- Select Product --",
+                preselectedProductId, ProductDTO::getProdId);
+    }
+
+    /**
+     * Loads the list of suppliers from the API.
+     */
     private void loadSuppliers() {
-        RetrofitClient.getSupplierApi(requireContext()).getAllSuppliers(0, 200)
-                .enqueue(new Callback<PageResponse<SupplierDTO>>() {
-                    public void onResponse(Call<PageResponse<SupplierDTO>> c,
-                                           Response<PageResponse<SupplierDTO>> r) {
-                        if (r.isSuccessful() && r.body() != null) {
-                            supplierList = r.body().getContent();
-                            populateSupplierSpinner();
-                        }
-                    }
-                    public void onFailure(Call<PageResponse<SupplierDTO>> c, Throwable t) {
-                        Log.e("PSDetail", "Supplier load failed: " + t.getMessage());
-                    }
-                });
-    }
-
-    private void populateSupplierSpinner() {
-        List<String> names = new ArrayList<>();
-        names.add("-- Select Supplier --");
-        for (SupplierDTO s : supplierList) names.add(s.getSupCompany());
-        spinnerSupplier.setAdapter(new ArrayAdapter<>(requireContext(),
-                android.R.layout.simple_spinner_item, names));
-        if (preselectedSupplierId != -1) {
-            for (int i = 0; i < supplierList.size(); i++) {
-                if (supplierList.get(i).getSupId().equals(preselectedSupplierId)) {
-                    spinnerSupplier.setSelection(i + 1); break;
-                }
+        supplierViewModel.getAllSuppliers(0, 200, null, "supCompany").observe(getViewLifecycleOwner(), resource -> {
+            if (resource.status == Resource.Status.SUCCESS && resource.data != null) {
+                supplierList = resource.data.getContent();
+                refreshSupplierSpinner();
             }
-        }
+        });
     }
 
+    private void refreshSupplierSpinner() {
+        SpinnerUtils.populateSpinner(requireContext(), binding.spinnerPSSupplier, supplierList,
+                SupplierDTO::getSupCompany, "-- Select Supplier --",
+                preselectedSupplierId, SupplierDTO::getSupId);
+    }
+
+    /**
+     * Handles arguments to determine if the fragment is in edit or add mode.
+     */
     private void handleArguments() {
         Bundle a = getArguments();
-        if (a != null && a.containsKey("productId")) {
+        if (a != null && a.containsKey("productId") && a.containsKey("supplierId")) {
             isEditing = true;
-            editProductId       = a.getLong("productId");
-            editSupplierId      = a.getLong("supplierId");
-            preselectedProductId  = editProductId;
+            editProductId = a.getLong("productId");
+            editSupplierId = a.getLong("supplierId");
+            preselectedProductId = editProductId;
             preselectedSupplierId = editSupplierId;
-            etCost.setText(a.getString("cost"));
-            tvMode.setText("Edit Product Supplier");
-            btnDelete.setVisibility(View.VISIBLE);
+            
+            binding.tvPSMode.setText("Edit Product Supplier");
+            binding.btnDeletePS.setVisibility(View.VISIBLE);
+
         } else {
-            tvMode.setText("Add Product Supplier");
-            btnDelete.setVisibility(View.GONE);
+            binding.tvPSMode.setText("Add Product Supplier");
+            binding.btnDeletePS.setVisibility(View.GONE);
         }
     }
 
+
+    /**
+     * Validates input and saves the product-supplier to the backend.
+     */
     private void save() {
-        if (spinnerProduct.getSelectedItemPosition() == 0) {
+        if (binding.spinnerPSProduct.getSelectedItemPosition() == 0) {
             Toast.makeText(getContext(), "Select a product", Toast.LENGTH_SHORT).show(); return;
         }
-        if (spinnerSupplier.getSelectedItemPosition() == 0) {
+        if (binding.spinnerPSSupplier.getSelectedItemPosition() == 0) {
             Toast.makeText(getContext(), "Select a supplier", Toast.LENGTH_SHORT).show(); return;
         }
-        String costStr = etCost.getText().toString().trim();
-        if (costStr.isEmpty()) {
-            etCost.setError("Enter cost"); return;
+
+        if (!InputValidator.isNotEmpty(binding.etPSCost, "Cost") ||
+            !InputValidator.isPositiveDecimal(binding.etPSCost, "Cost")) {
+            return;
         }
 
-        ProductDTO product   = productList.get(spinnerProduct.getSelectedItemPosition() - 1);
-        SupplierDTO supplier = supplierList.get(spinnerSupplier.getSelectedItemPosition() - 1);
-        BigDecimal cost;
-        try {
-            cost = new BigDecimal(costStr);
-        } catch (Exception e) {
-            etCost.setError("Invalid cost"); return;
-        }
+        ProductDTO product   = productList.get(binding.spinnerPSProduct.getSelectedItemPosition() - 1);
+        SupplierDTO supplier = supplierList.get(binding.spinnerPSSupplier.getSelectedItemPosition() - 1);
+        BigDecimal cost = new BigDecimal(binding.etPSCost.getText().toString().trim());
 
         ProductSupplierDTO dto = new ProductSupplierDTO(
                 product.getProdId(), supplier.getSupId(), cost);
 
-        ProductSupplierApi api = RetrofitClient.getProductSupplierApi(requireContext());
         if (isEditing) {
-            api.updateProductSupplier(editProductId, editSupplierId, dto)
-                    .enqueue(simpleCallback("Updated"));
+            psViewModel.updateProductSupplier(editProductId, editSupplierId, dto).observe(getViewLifecycleOwner(), resource -> {
+                if (resource.status == Resource.Status.SUCCESS) {
+                    Toast.makeText(getContext(), "Updated", Toast.LENGTH_SHORT).show();
+                    navigateBack();
+                } else if (resource.status == Resource.Status.ERROR) {
+                    Toast.makeText(getContext(), "Error: " + resource.message, Toast.LENGTH_SHORT).show();
+                }
+            });
         } else {
-            api.createProductSupplier(dto).enqueue(simpleCallback("Saved"));
+            psViewModel.createProductSupplier(dto).observe(getViewLifecycleOwner(), resource -> {
+                if (resource.status == Resource.Status.SUCCESS) {
+                    Toast.makeText(getContext(), "Saved", Toast.LENGTH_SHORT).show();
+                    navigateBack();
+                } else if (resource.status == Resource.Status.ERROR) {
+                    Toast.makeText(getContext(), "Error: " + resource.message, Toast.LENGTH_SHORT).show();
+                }
+            });
         }
     }
 
-    private Callback<ProductSupplierDTO> simpleCallback(String msg) {
-        return new Callback<>() {
-            public void onResponse(Call<ProductSupplierDTO> c, Response<ProductSupplierDTO> r) {
-                if (r.isSuccessful()) {
-                    Toast.makeText(getContext(), msg, Toast.LENGTH_SHORT).show();
-                    navigateBack();
-                } else {
-                    try {
-                        String err = r.errorBody().string();
-                        Log.e("PS_SAVE", "Error: " + err);
-                        Toast.makeText(getContext(), "Error " + r.code(), Toast.LENGTH_SHORT).show();
-                    } catch (Exception e) {
-                        Log.e("PS_SAVE", "Failed to read error");
-                    }
-                }
-            }
-            public void onFailure(Call<ProductSupplierDTO> c, Throwable t) {
-                Log.e("PS_SAVE", "Failure: " + t.getMessage());
-                Toast.makeText(getContext(), "Network error", Toast.LENGTH_SHORT).show();
-            }
-        };
-    }
-
+    /**
+     * Shows a confirmation dialog before deleting a product-supplier relationship.
+     */
     private void confirmDelete() {
-        new AlertDialog.Builder(requireContext())
-                .setTitle("Delete?")
-                .setPositiveButton("Yes", (d, w) ->
-                        RetrofitClient.getProductSupplierApi(requireContext())
-                                .deleteProductSupplier(editProductId, editSupplierId)
-                                .enqueue(new Callback<Void>() {
-                                    public void onResponse(Call<Void> c, Response<Void> r) {
-                                        navigateBack();
-                                    }
-                                    public void onFailure(Call<Void> c, Throwable t) {
-                                        Toast.makeText(getContext(), "Delete failed",
-                                                Toast.LENGTH_SHORT).show();
-                                    }
-                                }))
-                .setNegativeButton("No", null).show();
+        DialogUtils.showDeleteConfirmDialog(requireContext(), "Product Supplier", () ->
+                psViewModel.deleteProductSupplier(editProductId, editSupplierId).observe(getViewLifecycleOwner(), resource -> {
+                    if (resource.status == Resource.Status.SUCCESS) {
+                        Toast.makeText(getContext(), "Deleted", Toast.LENGTH_SHORT).show();
+                        navigateBack();
+                    } else if (resource.status == Resource.Status.ERROR) {
+                        Toast.makeText(getContext(), "Delete failed: " + resource.message, Toast.LENGTH_SHORT).show();
+                    }
+                }));
     }
 
+    /**
+     * Navigates back to the previous screen.
+     */
     private void navigateBack() {
-        ListFragment lf = (ListFragment) getParentFragment();
-        if (lf != null) lf.getChildFragmentManager().popBackStack();
+        NavHostFragment.findNavController(this).popBackStack();
     }
-}
+}

android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/PurchaseOrderDetailFragment.java

@@ -3,53 +3,107 @@ package com.example.petstoremobile.fragments.listfragments.detailfragments;
 import android.graphics.Color;
 import android.os.Bundle;
 import android.view.*;
-import android.widget.*;
-import androidx.annotation.NonNull;
-import androidx.fragment.app.Fragment;
-import com.example.petstoremobile.R;
-import com.example.petstoremobile.fragments.ListFragment;
+import android.widget.Toast;
 
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.fragment.app.Fragment;
+import androidx.lifecycle.ViewModelProvider;
+import androidx.navigation.fragment.NavHostFragment;
+
+import com.example.petstoremobile.databinding.FragmentPurchaseOrderDetailBinding;
+import com.example.petstoremobile.dtos.PurchaseOrderDTO;
+import com.example.petstoremobile.utils.Resource;
+import com.example.petstoremobile.viewmodels.PurchaseOrderViewModel;
+
+import dagger.hilt.android.AndroidEntryPoint;
+
+/**
+ * Fragment for displaying the information of a purchase order.
+ */
+@AndroidEntryPoint
 public class PurchaseOrderDetailFragment extends Fragment {
 
-    private TextView tvId, tvSupplier, tvDate, tvStatus;
-    private Button btnBack;
+    private FragmentPurchaseOrderDetailBinding binding;
+    private PurchaseOrderViewModel viewModel;
+    private long purchaseOrderId;
 
+    @Override
+    public void onCreate(@Nullable Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        viewModel = new ViewModelProvider(this).get(PurchaseOrderViewModel.class);
+    }
+
+    /**
+     * Inflates the layout.
+     */
     @Override
     public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
-        View view = inflater.inflate(R.layout.fragment_purchase_order_detail, container, false);
+        binding = FragmentPurchaseOrderDetailBinding.inflate(inflater, container, false);
+        return binding.getRoot();
+    }
 
-        tvId       = view.findViewById(R.id.tvPODetailId);
-        tvSupplier = view.findViewById(R.id.tvPODetailSupplier);
-        tvDate     = view.findViewById(R.id.tvPODetailDate);
-        tvStatus   = view.findViewById(R.id.tvPODetailStatus);
-        btnBack    = view.findViewById(R.id.btnPOBack);
+    /**
+     * Initializes views and populates order data from backend after the view is created.
+     */
+    @Override
+    public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
+        super.onViewCreated(view, savedInstanceState);
 
-        Bundle a = getArguments();
-        if (a != null) {
-            tvId.setText("PO #" + a.getLong("purchaseOrderId"));
-            tvSupplier.setText(a.getString("supplierName"));
-            tvDate.setText(a.getString("orderDate"));
+        handleArguments();
 
-            String status = a.getString("status", "");
-            tvStatus.setText(status);
-            switch (status) {
-                case "Completed":
-                    tvStatus.setTextColor(Color.parseColor("#4CAF50")); break;
-                case "Pending":
-                    tvStatus.setTextColor(Color.parseColor("#FF9800")); break;
-                case "Cancelled":
-                    tvStatus.setTextColor(Color.parseColor("#F44336")); break;
-                default:
-                    tvStatus.setTextColor(Color.parseColor("#9E9E9E")); break;
-            }
-        }
-
-        btnBack.setOnClickListener(v -> {
-            ListFragment lf = (ListFragment) getParentFragment();
-            if (lf != null) lf.getChildFragmentManager().popBackStack();
+        binding.btnPOBack.setOnClickListener(v -> {
+            NavHostFragment.findNavController(this).popBackStack();
         });
+    }
 
-        return view;
+    private void handleArguments() {
+        Bundle a = getArguments();
+        if (a != null && a.containsKey("purchaseOrderId")) {
+            purchaseOrderId = a.getLong("purchaseOrderId");
+            loadPurchaseOrderData();
+        }
+    }
+
+    private void loadPurchaseOrderData() {
+        viewModel.getPurchaseOrderById(purchaseOrderId).observe(getViewLifecycleOwner(), resource -> {
+            if (resource == null) return;
+            if (resource.status == Resource.Status.SUCCESS && resource.data != null) {
+                PurchaseOrderDTO po = resource.data;
+                binding.tvPODetailId.setText("PO #" + po.getPurchaseOrderId());
+                binding.tvPODetailSupplier.setText(po.getSupplierName());
+                binding.tvPODetailStore.setText(po.getStoreName() != null ? po.getStoreName() : "N/A");
+                binding.tvPODetailDate.setText(po.getOrderDate());
+
+                String status = po.getStatus() != null ? po.getStatus() : "";
+                binding.tvPODetailStatus.setText(status);
+                switch (status.toUpperCase()) {
+                    case "RECEIVED":
+                        binding.tvPODetailStatus.setTextColor(Color.parseColor("#4CAF50"));
+                        break;
+                    case "PLACED":
+                        binding.tvPODetailStatus.setTextColor(Color.parseColor("#2196F3"));
+                        break;
+                    case "PENDING":
+                        binding.tvPODetailStatus.setTextColor(Color.parseColor("#FF9800"));
+                        break;
+                    case "CANCELLED":
+                        binding.tvPODetailStatus.setTextColor(Color.parseColor("#F44336"));
+                        break;
+                    default:
+                        binding.tvPODetailStatus.setTextColor(Color.parseColor("#9E9E9E"));
+                        break;
+                }
+            } else if (resource.status == Resource.Status.ERROR) {
+                Toast.makeText(getContext(), "Failed to load order: " + resource.message, Toast.LENGTH_SHORT).show();
+            }
+        });
+    }
+
+    @Override
+    public void onDestroyView() {
+        super.onDestroyView();
+        binding = null;
     }
 }

android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/ServiceDetailFragment.java

@@ -2,75 +2,87 @@ package com.example.petstoremobile.fragments.listfragments.detailfragments;
 
 import android.os.Bundle;
 
-import androidx.appcompat.app.AlertDialog;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 import androidx.fragment.app.Fragment;
+import androidx.lifecycle.ViewModelProvider;
+import androidx.navigation.fragment.NavHostFragment;
 
-import android.util.Log;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
-import android.widget.Button;
-import android.widget.EditText;
-import android.widget.TextView;
 import android.widget.Toast;
 
 import com.example.petstoremobile.R;
-import com.example.petstoremobile.api.RetrofitClient;
-import com.example.petstoremobile.api.ServiceApi;
+import com.example.petstoremobile.databinding.FragmentServiceDetailBinding;
 import com.example.petstoremobile.dtos.ServiceDTO;
-import com.example.petstoremobile.fragments.ListFragment;
-import com.example.petstoremobile.fragments.listfragments.ServiceFragment;
 import com.example.petstoremobile.utils.ActivityLogger;
+import com.example.petstoremobile.utils.DialogUtils;
 import com.example.petstoremobile.utils.InputValidator;
+import com.example.petstoremobile.utils.Resource;
+import com.example.petstoremobile.viewmodels.ServiceViewModel;
 
-import retrofit2.Call;
-import retrofit2.Callback;
-import retrofit2.Response;
+import dagger.hilt.android.AndroidEntryPoint;
 
+/**
+ * Fragment for displaying and editing service details.
+ */
+@AndroidEntryPoint
 public class ServiceDetailFragment extends Fragment {
 
-    private TextView tvMode, tvServiceId;
-    private EditText etServiceName, etServiceDesc, etServiceDuration, etServicePrice;
-    private Button btnSaveService, btnDeleteService, btnBack;
-    private int serviceId;
+    private FragmentServiceDetailBinding binding;
+    private long serviceId;
     private boolean isEditing = false;
-    private ServiceFragment serviceFragment;
 
-    //set the service fragment to the parent so we refer back to service view when save or delete is done
-    public void setServiceFragment(ServiceFragment fragment) {
-        this.serviceFragment = fragment;
+    private ServiceViewModel viewModel;
+
+    @Override
+    public void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        viewModel = new ViewModelProvider(this).get(ServiceViewModel.class);
     }
 
     @Override
-    public View onCreateView(LayoutInflater inflater, ViewGroup container,
+    public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
-        View view = inflater.inflate(R.layout.fragment_service_detail, container, false);
+        binding = FragmentServiceDetailBinding.inflate(inflater, container, false);
+        return binding.getRoot();
+    }
+
+    @Override
+    public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
+        super.onViewCreated(view, savedInstanceState);
 
         //get controls from layout and display the view depending on the mode
-        initViews(view);
         handleArguments();
 
         //set button click listeners
-        btnBack.setOnClickListener(v -> navigateBack());
-        btnSaveService.setOnClickListener(v -> saveService());
-        btnDeleteService.setOnClickListener(v -> deleteService());
-
-        return view;
+        binding.btnBack.setOnClickListener(v -> navigateBack());
+        binding.btnSaveService.setOnClickListener(v -> saveService());
+        binding.btnDeleteService.setOnClickListener(v -> deleteService());
     }
 
-    //Method to Update or Add a service
+    @Override
+    public void onDestroyView() {
+        super.onDestroyView();
+        binding = null;
+    }
+
+    /**
+     * Handles the saving of service data (adding or updating).
+     */
     private void saveService() {
         // Validates all fields using InputValidator
-        if (!InputValidator.isNotEmpty(etServiceName, "Service Name")) return;
-        if (!InputValidator.isNotEmpty(etServiceDesc, "Description")) return;
-        if (!InputValidator.isPositiveInteger(etServiceDuration, "Duration")) return;
-        if (!InputValidator.isPositiveDecimal(etServicePrice, "Price")) return;
+        if (!InputValidator.isNotEmpty(binding.etServiceName, "Service Name")) return;
+        if (!InputValidator.isNotEmpty(binding.etServiceDesc, "Description")) return;
+        if (!InputValidator.isPositiveInteger(binding.etServiceDuration, "Duration")) return;
+        if (!InputValidator.isPositiveDecimal(binding.etServicePrice, "Price")) return;
 
         //get all the values from the fields
-        String name = etServiceName.getText().toString().trim();
-        String desc = etServiceDesc.getText().toString().trim();
-        int duration = Integer.parseInt(etServiceDuration.getText().toString().trim());
-        double price = Double.parseDouble(etServicePrice.getText().toString().trim());
+        String name = binding.etServiceName.getText().toString().trim();
+        String desc = binding.etServiceDesc.getText().toString().trim();
+        int duration = Integer.parseInt(binding.etServiceDuration.getText().toString().trim());
+        double price = Double.parseDouble(binding.etServicePrice.getText().toString().trim());
 
         //create a service object to send to the API
         ServiceDTO serviceDTO = new ServiceDTO();
@@ -79,130 +91,94 @@ public class ServiceDetailFragment extends Fragment {
         serviceDTO.setServiceDuration(duration);
         serviceDTO.setServicePrice(price);
 
-        ServiceApi serviceApi = RetrofitClient.getServiceApi(requireContext());
-
         //check if the service is being edited or added
         if (isEditing) {
             // Update existing service
-            serviceDTO.setServiceId((long) serviceId);
-            serviceApi.updateService((long) serviceId, serviceDTO).enqueue(new Callback<ServiceDTO>() {
-                @Override
-                public void onResponse(Call<ServiceDTO> call, Response<ServiceDTO> response) {
-                    if (response.isSuccessful()) {
-                        ActivityLogger.logChange(requireContext(), "Service", "UPDATED", serviceId);
-                        Toast.makeText(getContext(), "Service updated successfully!", Toast.LENGTH_SHORT).show();
-                        navigateBack();
-                    } else {
-                        Toast.makeText(getContext(), "Failed to update service: " + response.code(), Toast.LENGTH_SHORT).show();
-                    }
-                }
-
-                @Override
-                public void onFailure(Call<ServiceDTO> call, Throwable t) {
-                    ActivityLogger.logException(requireContext(), "ServiceDetailFragment.updateService", new Exception(t));
-                    Log.e("ServiceDetailFragment", "Error updating service", t);
-                    Toast.makeText(getContext(), "Error: " + t.getMessage(), Toast.LENGTH_SHORT).show();
+            serviceDTO.setServiceId(serviceId);
+            viewModel.updateService(serviceId, serviceDTO).observe(getViewLifecycleOwner(), resource -> {
+                if (resource.status == Resource.Status.SUCCESS) {
+                    ActivityLogger.logChange(requireContext(), "Service", "UPDATED", (int) serviceId);
+                    Toast.makeText(getContext(), "Service updated successfully!", Toast.LENGTH_SHORT).show();
+                    navigateBack();
+                } else if (resource.status == Resource.Status.ERROR) {
+                    Toast.makeText(getContext(), "Error: " + resource.message, Toast.LENGTH_SHORT).show();
                 }
             });
         } else {
-            // Add new service
-            serviceApi.createService(serviceDTO).enqueue(new Callback<ServiceDTO>() {
-                @Override
-                public void onResponse(Call<ServiceDTO> call, Response<ServiceDTO> response) {
-                    if (response.isSuccessful()) {
-                        ActivityLogger.log(requireContext(), "Added new Service: " + name);
-                        Toast.makeText(getContext(), "Service added successfully!", Toast.LENGTH_SHORT).show();
-                        navigateBack();
-                    } else {
-                        Toast.makeText(getContext(), "Failed to add service: " + response.code(), Toast.LENGTH_SHORT).show();
-                    }
-                }
-
-                @Override
-                public void onFailure(Call<ServiceDTO> call, Throwable t) {
-                    ActivityLogger.logException(requireContext(), "ServiceDetailFragment.createService", new Exception(t));
-                    Log.e("ServiceDetailFragment", "Error adding service", t);
-                    Toast.makeText(getContext(), "Error: " + t.getMessage(), Toast.LENGTH_SHORT).show();
+            viewModel.createService(serviceDTO).observe(getViewLifecycleOwner(), resource -> {
+                if (resource.status == Resource.Status.SUCCESS) {
+                    ActivityLogger.log(requireContext(), "Added new Service: " + name);
+                    Toast.makeText(getContext(), "Service added successfully!", Toast.LENGTH_SHORT).show();
+                    navigateBack();
+                } else if (resource.status == Resource.Status.ERROR) {
+                    Toast.makeText(getContext(), "Error: " + resource.message, Toast.LENGTH_SHORT).show();
                 }
             });
         }
     }
 
-    //Method to Delete a service
+    /**
+     * Displays a confirmation dialog and handles the deletion of a service.
+     */
     private void deleteService() {
-        //Alert the user to confirm the delete
-        new AlertDialog.Builder(requireContext())
-                .setTitle("Delete Service")
-                .setMessage("Are you sure you want to delete " + etServiceName.getText().toString() + "?")
-                .setPositiveButton("Delete", (dialog, which) -> {
-                    ServiceApi serviceApi = RetrofitClient.getServiceApi(requireContext());
-                    serviceApi.deleteService((long) serviceId).enqueue(new Callback<Void>() {
-                        @Override
-                        public void onResponse(Call<Void> call, Response<Void> response) {
-                            if (response.isSuccessful()) {
-                                ActivityLogger.logChange(requireContext(), "Service", "DELETED", serviceId);
-                                Toast.makeText(getContext(), "Service deleted successfully!", Toast.LENGTH_SHORT).show();
-                                navigateBack();
-                            } else {
-                                Toast.makeText(getContext(), "Failed to delete service: " + response.code(), Toast.LENGTH_SHORT).show();
-                            }
-                        }
-
-                        @Override
-                        public void onFailure(Call<Void> call, Throwable t) {
-                            ActivityLogger.logException(requireContext(), "ServiceDetailFragment.deleteService", new Exception(t));
-                            Log.e("ServiceDetailFragment", "Error deleting service", t);
-                            Toast.makeText(getContext(), "Error: " + t.getMessage(), Toast.LENGTH_SHORT).show();
-                        }
-                    });
-                })
-                .setNegativeButton("Cancel", null)
-                .show();
+        DialogUtils.showDeleteConfirmDialog(requireContext(), "Service", () -> 
+                viewModel.deleteService(serviceId).observe(getViewLifecycleOwner(), resource -> {
+                    if (resource.status == Resource.Status.SUCCESS) {
+                        ActivityLogger.logChange(requireContext(), "Service", "DELETED", (int) serviceId);
+                        Toast.makeText(getContext(), "Service deleted successfully!", Toast.LENGTH_SHORT).show();
+                        navigateBack();
+                    } else if (resource.status == Resource.Status.ERROR) {
+                        Toast.makeText(getContext(), "Delete failed: " + resource.message, Toast.LENGTH_SHORT).show();
+                    }
+                }));
     }
 
-    //Helper method to navigate back to the list
+    /**
+     * Navigates back to the previous screen.
+     */
     private void navigateBack() {
-        ListFragment listFragment = (ListFragment) getParentFragment();
-        if (listFragment != null) {
-            listFragment.getChildFragmentManager().popBackStack();
-        }
+        NavHostFragment.findNavController(this).popBackStack();
     }
 
-    //helper function to check if service is being edited or added and show the view accordingly
+    /**
+     * Handles arguments passed to the fragment to determine if it's in edit or add mode.
+     */
     private void handleArguments() {
         // Service is being edited if the bundle contains a serviceId
         if (getArguments() != null && getArguments().containsKey("serviceId")) {
             // Get service data from arguments and populate fields
             isEditing = true;
-            serviceId = getArguments().getInt("serviceId");
-            tvMode.setText("Edit Service");
-            tvServiceId.setText("ID: " + serviceId);
-            etServiceName.setText(getArguments().getString("serviceName"));
-            etServiceDesc.setText(getArguments().getString("serviceDesc"));
-            etServiceDuration.setText(String.valueOf(getArguments().getInt("serviceDuration")));
-            etServicePrice.setText(String.valueOf(getArguments().getDouble("servicePrice")));
-            btnDeleteService.setVisibility(View.VISIBLE);
+            serviceId = getArguments().getLong("serviceId");
+            binding.tvMode.setText("Edit Service");
+            binding.tvServiceId.setText("ID: " + serviceId);
+            binding.btnDeleteService.setVisibility(View.VISIBLE);
+            loadServiceData();
         } else {
             // Service is being added
             // Set default values for add a new service
             isEditing = false;
-            tvMode.setText("Add Service");
-            tvServiceId.setVisibility(View.GONE);
-            btnDeleteService.setVisibility(View.GONE);
-            btnSaveService.setText("Add");
+            binding.tvMode.setText("Add Service");
+            binding.tvServiceId.setVisibility(View.GONE);
+            binding.btnDeleteService.setVisibility(View.GONE);
+            binding.btnSaveService.setText("Add");
         }
     }
 
-    //helper function to get controls from layout
-    private void initViews(View view) {
-        tvMode = view.findViewById(R.id.tvMode);
-        tvServiceId = view.findViewById(R.id.tvServiceId);
-        etServiceName = view.findViewById(R.id.etServiceName);
-        etServiceDesc = view.findViewById(R.id.etServiceDesc);
-        etServiceDuration = view.findViewById(R.id.etServiceDuration);
-        etServicePrice = view.findViewById(R.id.etServicePrice);
-        btnSaveService = view.findViewById(R.id.btnSaveService);
-        btnDeleteService = view.findViewById(R.id.btnDeleteService);
-        btnBack = view.findViewById(R.id.btnBack);
+    /**
+     * Fetches specific service details from the backend using the ID.
+     */
+    private void loadServiceData() {
+        viewModel.getServiceById(serviceId).observe(getViewLifecycleOwner(), resource -> {
+            if (resource == null) return;
+            if (resource.status == Resource.Status.SUCCESS && resource.data != null) {
+                ServiceDTO s = resource.data;
+                binding.etServiceName.setText(s.getServiceName());
+                binding.etServiceDesc.setText(s.getServiceDesc());
+                binding.etServiceDuration.setText(String.valueOf(s.getServiceDuration()));
+                binding.etServicePrice.setText(String.valueOf(s.getServicePrice()));
+            } else if (resource.status == Resource.Status.ERROR) {
+                Toast.makeText(getContext(), "Failed to load service: " + resource.message, Toast.LENGTH_SHORT).show();
+            }
+        });
     }
 }

android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/detailfragments/SupplierDetailFragment.java

@@ -2,77 +2,91 @@ package com.example.petstoremobile.fragments.listfragments.detailfragments;
 
 import android.os.Bundle;
 
-import androidx.appcompat.app.AlertDialog;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 import androidx.fragment.app.Fragment;
+import androidx.lifecycle.ViewModelProvider;
+import androidx.navigation.fragment.NavHostFragment;
 
-import android.util.Log;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
-import android.widget.Button;
-import android.widget.EditText;
-import android.widget.TextView;
 import android.widget.Toast;
 
-import com.example.petstoremobile.R;
-import com.example.petstoremobile.api.RetrofitClient;
-import com.example.petstoremobile.api.SupplierApi;
+import com.example.petstoremobile.databinding.FragmentSupplierDetailBinding;
 import com.example.petstoremobile.dtos.SupplierDTO;
-import com.example.petstoremobile.fragments.ListFragment;
-import com.example.petstoremobile.fragments.listfragments.SupplierFragment;
 import com.example.petstoremobile.utils.ActivityLogger;
+import com.example.petstoremobile.utils.DialogUtils;
 import com.example.petstoremobile.utils.InputValidator;
+import com.example.petstoremobile.utils.Resource;
+import com.example.petstoremobile.utils.UIUtils;
+import com.example.petstoremobile.viewmodels.SupplierViewModel;
 
-import retrofit2.Call;
-import retrofit2.Callback;
-import retrofit2.Response;
+import dagger.hilt.android.AndroidEntryPoint;
 
+/**
+ * Fragment for displaying and editing supplier details.
+ */
+@AndroidEntryPoint
 public class SupplierDetailFragment extends Fragment {
 
-    private TextView tvMode, tvSupId;
-    private EditText etSupCompany, etSupContactFirstName, etSupContactLastName, etSupEmail, etSupPhone;
-    private Button btnSaveSupplier, btnDeleteSupplier, btnBack;
-    private int supId;
+    private FragmentSupplierDetailBinding binding;
+    private long supId;
     private boolean isEditing = false;
-    private SupplierFragment supplierFragment;
 
-    //set the supplier fragment to the parent so we refer back to supplier view when save or delete is done
-    public void setSupplierFragment(SupplierFragment fragment) {
-        this.supplierFragment = fragment;
+    private SupplierViewModel viewModel;
+
+    @Override
+    public void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        viewModel = new ViewModelProvider(this).get(SupplierViewModel.class);
     }
 
     @Override
-    public View onCreateView(LayoutInflater inflater, ViewGroup container,
+    public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
-        View view = inflater.inflate(R.layout.fragment_supplier_detail, container, false);
+        binding = FragmentSupplierDetailBinding.inflate(inflater, container, false);
+        return binding.getRoot();
+    }
+
+    @Override
+    public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
+        super.onViewCreated(view, savedInstanceState);
+
+        // Add phone number formatting (CA) and limit length to 14 characters
+        UIUtils.formatPhoneInput(binding.etSupPhone);
 
-        //get controls from layout and display the view depending on the mode
-        initViews(view);
         handleArguments();
 
         //set button click listeners
-        btnBack.setOnClickListener(v -> navigateBack());
-        btnSaveSupplier.setOnClickListener(v -> saveSupplier());
-        btnDeleteSupplier.setOnClickListener(v -> deleteSupplier());
-
-        return view;
+        binding.btnBack.setOnClickListener(v -> navigateBack());
+        binding.btnSaveSupplier.setOnClickListener(v -> saveSupplier());
+        binding.btnDeleteSupplier.setOnClickListener(v -> deleteSupplier());
     }
 
-    //Method to Update or Add a supplier
+    @Override
+    public void onDestroyView() {
+        super.onDestroyView();
+        binding = null;
+    }
+
+    /**
+     * Handles the saving of supplier data (adding or updating).
+     */
     private void saveSupplier() {
         // Validates all fields using InputValidator
-        if (!InputValidator.isNotEmpty(etSupCompany, "Company Name")) return;
-        if (!InputValidator.isNotEmpty(etSupContactFirstName, "First Name")) return;
-        if (!InputValidator.isNotEmpty(etSupContactLastName, "Last Name")) return;
-        if (!InputValidator.isValidEmail(etSupEmail)) return;
-        if (!InputValidator.isValidPhone(etSupPhone)) return;
+        if (!InputValidator.isNotEmpty(binding.etSupCompany, "Company Name")) return;
+        if (!InputValidator.isNotEmpty(binding.etSupContactFirstName, "First Name")) return;
+        if (!InputValidator.isNotEmpty(binding.etSupContactLastName, "Last Name")) return;
+        if (!InputValidator.isValidEmail(binding.etSupEmail)) return;
+        if (!InputValidator.isValidPhone(binding.etSupPhone)) return;
 
         //get all the values from the fields
-        String company = etSupCompany.getText().toString().trim();
-        String firstName = etSupContactFirstName.getText().toString().trim();
-        String lastName = etSupContactLastName.getText().toString().trim();
-        String email = etSupEmail.getText().toString().trim();
-        String phone = etSupPhone.getText().toString().trim();
+        String company = binding.etSupCompany.getText().toString().trim();
+        String firstName = binding.etSupContactFirstName.getText().toString().trim();
+        String lastName = binding.etSupContactLastName.getText().toString().trim();
+        String email = binding.etSupEmail.getText().toString().trim();
+        String phone = binding.etSupPhone.getText().toString().trim();
 
         //create a supplier object to send to the API
         SupplierDTO supplierDTO = new SupplierDTO();
@@ -82,137 +96,97 @@ public class SupplierDetailFragment extends Fragment {
         supplierDTO.setSupEmail(email);
         supplierDTO.setSupPhone(phone);
 
-        SupplierApi supplierApi = RetrofitClient.getSupplierApi(requireContext());
-
         //check if the supplier is being edited or added
         if (isEditing) {
             // Update existing supplier
-            supplierDTO.setSupId((long) supId);
-            supplierApi.updateSupplier((long) supId, supplierDTO).enqueue(new Callback<SupplierDTO>() {
-                @Override
-                public void onResponse(Call<SupplierDTO> call, Response<SupplierDTO> response) {
-                    if (response.isSuccessful()) {
-                        ActivityLogger.logChange(requireContext(), "Supplier", "UPDATED", supId);
-                        Toast.makeText(getContext(), "Supplier updated successfully!", Toast.LENGTH_SHORT).show();
-                        navigateBack();
-                    } else {
-                        Toast.makeText(getContext(), "Failed to update supplier: " + response.code(), Toast.LENGTH_SHORT).show();
-                    }
-                }
-
-                @Override
-                public void onFailure(Call<SupplierDTO> call, Throwable t) {
-                    ActivityLogger.logException(requireContext(), "SupplierDetailFragment.updateSupplier", new Exception(t));
-                    Log.e("SupplierDetailFragment", "Error updating supplier", t);
-                    Toast.makeText(getContext(), "Error: " + t.getMessage(), Toast.LENGTH_SHORT).show();
+            supplierDTO.setSupId(supId);
+            viewModel.updateSupplier(supId, supplierDTO).observe(getViewLifecycleOwner(), resource -> {
+                if (resource.status == Resource.Status.SUCCESS) {
+                    ActivityLogger.logChange(requireContext(), "Supplier", "UPDATED", (int) supId);
+                    Toast.makeText(getContext(), "Supplier updated successfully!", Toast.LENGTH_SHORT).show();
+                    navigateBack();
+                } else if (resource.status == Resource.Status.ERROR) {
+                    Toast.makeText(getContext(), "Error: " + resource.message, Toast.LENGTH_SHORT).show();
                 }
             });
         } else {
             // Add new supplier
-            supplierApi.createSupplier(supplierDTO).enqueue(new Callback<SupplierDTO>() {
-                @Override
-                public void onResponse(Call<SupplierDTO> call, Response<SupplierDTO> response) {
-                    if (response.isSuccessful()) {
-                        ActivityLogger.log(requireContext(), "Added new Supplier: " + company);
-                        Toast.makeText(getContext(), "Supplier added successfully!", Toast.LENGTH_SHORT).show();
-                        navigateBack();
-                    } else {
-                        Toast.makeText(getContext(), "Failed to add supplier: " + response.code(), Toast.LENGTH_SHORT).show();
-                    }
-                }
-
-                @Override
-                public void onFailure(Call<SupplierDTO> call, Throwable t) {
-                    ActivityLogger.logException(requireContext(), "SupplierDetailFragment.createSupplier", new Exception(t));
-                    Log.e("SupplierDetailFragment", "Error adding supplier", t);
-                    Toast.makeText(getContext(), "Error: " + t.getMessage(), Toast.LENGTH_SHORT).show();
+            viewModel.createSupplier(supplierDTO).observe(getViewLifecycleOwner(), resource -> {
+                if (resource.status == Resource.Status.SUCCESS) {
+                    ActivityLogger.log(requireContext(), "Added new Supplier: " + company);
+                    Toast.makeText(getContext(), "Supplier added successfully!", Toast.LENGTH_SHORT).show();
+                    navigateBack();
+                } else if (resource.status == Resource.Status.ERROR) {
+                    Toast.makeText(getContext(), "Error: " + resource.message, Toast.LENGTH_SHORT).show();
                 }
             });
         }
     }
 
-    //Method to Delete a supplier
+    /**
+     * Displays a confirmation dialog and handles the deletion of a supplier.
+     */
     private void deleteSupplier() {
-        //Alert the user to confirm the delete
-        new AlertDialog.Builder(requireContext())
-                .setTitle("Delete Supplier")
-                .setMessage("Are you sure you want to delete " + etSupCompany.getText().toString() + "?")
-                .setPositiveButton("Delete", (dialog, which) -> {
-                    SupplierApi supplierApi = RetrofitClient.getSupplierApi(requireContext());
-                    supplierApi.deleteSupplier((long) supId).enqueue(new Callback<Void>() {
-                        @Override
-                        public void onResponse(Call<Void> call, Response<Void> response) {
-                            if (response.isSuccessful()) {
-                                ActivityLogger.logChange(requireContext(), "Supplier", "DELETED", supId);
-                                Toast.makeText(getContext(), "Supplier deleted successfully!", Toast.LENGTH_SHORT).show();
-                                navigateBack();
-                            } else {
-                                Toast.makeText(getContext(), "Failed to delete supplier: " + response.code(), Toast.LENGTH_SHORT).show();
-                            }
-                        }
-
-                        @Override
-                        public void onFailure(Call<Void> call, Throwable t) {
-                            ActivityLogger.logException(requireContext(), "SupplierDetailFragment.deleteSupplier", new Exception(t));
-                            Log.e("SupplierDetailFragment", "Error deleting supplier", t);
-                            Toast.makeText(getContext(), "Error: " + t.getMessage(), Toast.LENGTH_SHORT).show();
-                        }
-                    });
-                })
-                .setNegativeButton("Cancel", null)
-                .show();
+        DialogUtils.showDeleteConfirmDialog(requireContext(), "Supplier", () ->
+                viewModel.deleteSupplier(supId).observe(getViewLifecycleOwner(), resource -> {
+                    if (resource.status == Resource.Status.SUCCESS) {
+                        ActivityLogger.logChange(requireContext(), "Supplier", "DELETED", (int) supId);
+                        Toast.makeText(getContext(), "Supplier deleted successfully!", Toast.LENGTH_SHORT).show();
+                        navigateBack();
+                    } else if (resource.status == Resource.Status.ERROR) {
+                        Toast.makeText(getContext(), "Delete failed: " + resource.message, Toast.LENGTH_SHORT).show();
+                    }
+                }));
     }
 
-    //Helper method to navigate back to the list
+    /**
+     * Navigates back to the previous screen.
+     */
     private void navigateBack() {
-        ListFragment listFragment = (ListFragment) getParentFragment();
-        if (listFragment != null) {
-            listFragment.getChildFragmentManager().popBackStack();
-        }
+        NavHostFragment.findNavController(this).popBackStack();
     }
 
-    //helper function to check if supplier is being edited or added and show the view accordingly
+    /**
+     * Handles arguments passed to the fragment to determine if it's in edit or add mode.
+     */
     private void handleArguments() {
         // Supplier is being edited if the bundle contains a supId
         if (getArguments() != null && getArguments().containsKey("supId")) {
             // Get supplier data from arguments and populate fields
             isEditing = true;
-            supId = getArguments().getInt("supId");
-            tvMode.setText("Edit Supplier");
-            tvSupId.setText("ID: " + supId);
-            etSupCompany.setText(getArguments().getString("supCompany"));
-            etSupContactFirstName.setText(getArguments().getString("supContactFirstName"));
-            etSupContactLastName.setText(getArguments().getString("supContactLastName"));
-            etSupEmail.setText(getArguments().getString("supEmail"));
-            etSupPhone.setText(getArguments().getString("supPhone"));
-            btnDeleteSupplier.setVisibility(View.VISIBLE);
+            supId = getArguments().getLong("supId");
+            binding.tvMode.setText("Edit Supplier");
+            binding.tvSupId.setText("ID: " + supId);
+            binding.tvSupId.setVisibility(View.VISIBLE);
+            binding.btnDeleteSupplier.setVisibility(View.VISIBLE);
+            loadSupplierData();
         } else {
             // Supplier is being added
             // Set default values for add a new supplier
             isEditing = false;
-            tvMode.setText("Add Supplier");
-            tvSupId.setVisibility(View.GONE);
-            btnDeleteSupplier.setVisibility(View.GONE);
-            btnSaveSupplier.setText("Add");
+            binding.tvMode.setText("Add Supplier");
+            binding.tvSupId.setVisibility(View.GONE);
+            binding.btnDeleteSupplier.setVisibility(View.GONE);
+            binding.btnSaveSupplier.setText("Add");
         }
     }
 
-    //helper function to get controls from layout
-    private void initViews(View view) {
-        tvMode = view.findViewById(R.id.tvMode);
-        tvSupId = view.findViewById(R.id.tvSupId);
-        etSupCompany = view.findViewById(R.id.etSupCompany);
-        etSupContactFirstName = view.findViewById(R.id.etSupContactFirstName);
-        etSupContactLastName = view.findViewById(R.id.etSupContactLastName);
-        etSupEmail = view.findViewById(R.id.etSupEmail);
-        etSupPhone = view.findViewById(R.id.etSupPhone);
-
-        // Add phone number formatting (CA) and limit length to 14 characters
-        etSupPhone.addTextChangedListener(new android.telephony.PhoneNumberFormattingTextWatcher("CA"));
-        etSupPhone.setFilters(new android.text.InputFilter[]{new android.text.InputFilter.LengthFilter(14)});
-
-        btnSaveSupplier = view.findViewById(R.id.btnSaveSupplier);
-        btnDeleteSupplier = view.findViewById(R.id.btnDeleteSupplier);
-        btnBack = view.findViewById(R.id.btnBack);
+    /**
+     * Fetches specific supplier details from the backend using the ID.
+     */
+    private void loadSupplierData() {
+        viewModel.getSupplierById(supId).observe(getViewLifecycleOwner(), resource -> {
+            if (resource == null) return;
+            if (resource.status == Resource.Status.SUCCESS && resource.data != null) {
+                SupplierDTO s = resource.data;
+                binding.etSupCompany.setText(s.getSupCompany());
+                binding.etSupContactFirstName.setText(s.getSupContactFirstName());
+                binding.etSupContactLastName.setText(s.getSupContactLastName());
+                binding.etSupEmail.setText(s.getSupEmail());
+                binding.etSupPhone.setText(s.getSupPhone());
+            } else if (resource.status == Resource.Status.ERROR) {
+                Toast.makeText(getContext(), "Failed to load supplier: " + resource.message, Toast.LENGTH_SHORT).show();
+            }
+        });
     }
 }

android/app/src/main/java/com/example/petstoremobile/fragments/listfragments/listprofilefragments/PetProfileFragment.java

@@ -1,262 +1,210 @@
 package com.example.petstoremobile.fragments.listfragments.listprofilefragments;
 
-import android.Manifest;
-import android.app.Activity;
-import android.content.Intent;
-import android.content.pm.PackageManager;
-import android.graphics.Color;
 import android.net.Uri;
 import android.os.Bundle;
 
-import androidx.activity.result.ActivityResultLauncher;
-import androidx.activity.result.contract.ActivityResultContracts;
-import androidx.appcompat.app.AlertDialog;
-import androidx.core.content.ContextCompat;
-import androidx.core.content.FileProvider;
+import androidx.annotation.NonNull;
 import androidx.fragment.app.Fragment;
+import androidx.lifecycle.ViewModelProvider;
+import androidx.navigation.fragment.NavHostFragment;
 
-import android.provider.MediaStore;
 import android.util.Log;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
-import android.widget.Button;
-import android.widget.ImageView;
-import android.widget.TextView;
 import android.widget.Toast;
 
-import com.bumptech.glide.Glide;
-import com.bumptech.glide.load.engine.DiskCacheStrategy;
 import com.example.petstoremobile.R;
 import com.example.petstoremobile.api.PetApi;
-import com.example.petstoremobile.api.RetrofitClient;
-import com.example.petstoremobile.fragments.ListFragment;
-import com.example.petstoremobile.fragments.listfragments.detailfragments.PetDetailFragment;
+import com.example.petstoremobile.api.auth.TokenManager;
+import com.example.petstoremobile.databinding.FragmentPetProfileBinding;
+import com.example.petstoremobile.dtos.PetDTO;
+import com.example.petstoremobile.utils.FileUtils;
+import com.example.petstoremobile.utils.GlideUtils;
+import com.example.petstoremobile.utils.ImagePickerHelper;
+import com.example.petstoremobile.utils.Resource;
+import com.example.petstoremobile.viewmodels.PetViewModel;
 
 import java.io.File;
-import java.io.FileOutputStream;
-import java.io.InputStream;
 import java.util.Locale;
 
+import javax.inject.Inject;
+import javax.inject.Named;
+
+import dagger.hilt.android.AndroidEntryPoint;
 import okhttp3.MediaType;
 import okhttp3.MultipartBody;
 import okhttp3.RequestBody;
-import retrofit2.Call;
-import retrofit2.Callback;
-import retrofit2.Response;
 
+@AndroidEntryPoint
 public class PetProfileFragment extends Fragment {
 
-    private TextView tvPetName, tvPetSpecies, tvPetBreed, tvPetAge, tvPetPrice;
-    private Button btnBack, btnEditPet, btnChangePhoto;
-    private ImageView imgPet;
-    private Uri photoUri;
-    private int petId;
+    private FragmentPetProfileBinding binding;
+    private long petId;
+    private boolean hasImage = false;
 
-    // launchers for camera and gallery
-    private ActivityResultLauncher<Intent> galleryLauncher;
-    private ActivityResultLauncher<Uri> cameraLauncher;
-    private ActivityResultLauncher<String> permissionLauncher;
+    @Inject @Named("baseUrl") String baseUrl;
+    @Inject TokenManager tokenManager;
+
+    private PetViewModel viewModel;
+    private ImagePickerHelper imagePickerHelper;
 
 
+    /**
+     * Initializes activity launchers for gallery, camera, and permissions.
+     */
     @Override
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
+        viewModel = new ViewModelProvider(this).get(PetViewModel.class);
 
-        // Launcher to open gallery to select image
-        galleryLauncher = registerForActivityResult(
-                new ActivityResultContracts.StartActivityForResult(),
-                result -> {
-                    if (result.getResultCode() == Activity.RESULT_OK && result.getData() != null) {
-                        Uri selectedImage = result.getData().getData();
-                        uploadPetImage(selectedImage);
-                    }
-                }
-        );
+        imagePickerHelper = new ImagePickerHelper(this, "pet_photo.jpg", new ImagePickerHelper.ImagePickerListener() {
+            @Override
+            public void onImagePicked(Uri uri) {
+                uploadPetImage(uri);
+            }
 
-        // Launcher for camera to open and capture image
-        cameraLauncher = registerForActivityResult(
-                new ActivityResultContracts.TakePicture(),
-                success -> {
-                    if (success) {
-                        uploadPetImage(photoUri);
-                    }
-                }
-        );
-
-        // Launcher to request camera permission
-        permissionLauncher = registerForActivityResult(
-                new ActivityResultContracts.RequestPermission(),
-                granted -> {
-                    if (granted) {
-                        launchCamera();
-                    } else {
-                        new AlertDialog.Builder(requireContext())
-                                .setTitle("Permission Required")
-                                .setMessage("Please grant camera permission to use this feature")
-                                .setPositiveButton("Open Settings", (dialog, which) -> {
-                                    Intent intent = new Intent(android.provider.Settings.ACTION_APPLICATION_DETAILS_SETTINGS);
-                                    intent.setData(Uri.fromParts("package", requireContext().getPackageName(), null));
-                                    startActivity(intent);
-                                })
-                                .setNegativeButton("Cancel", null)
-                                .show();
-                    }
-                }
-        );
+            @Override
+            public void onImageRemoved() {
+                deletePetImage();
+            }
+        });
     }
 
+    /**
+     * Inflates the layout using view binding, initializes views, and sets up click listeners.
+     */
     @Override
-    public View onCreateView(LayoutInflater inflater, ViewGroup container,
+    public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
-        View view = inflater.inflate(R.layout.fragment_pet_profile, container, false);
-
-        // Initialize views
-        tvPetName = view.findViewById(R.id.tvPetName);
-        tvPetSpecies = view.findViewById(R.id.tvPetSpecies);
-        tvPetBreed = view.findViewById(R.id.tvPetBreed);
-        tvPetAge = view.findViewById(R.id.tvPetAge);
-        tvPetPrice = view.findViewById(R.id.tvPetPrice);
-        btnBack = view.findViewById(R.id.btnBack);
-        btnEditPet = view.findViewById(R.id.btnEditPet);
-        btnChangePhoto = view.findViewById(R.id.btnChangePhoto);
-        imgPet = view.findViewById(R.id.imgPet);
-
+        binding = FragmentPetProfileBinding.inflate(inflater, container, false);
 
         // Set pet details to display
         if (getArguments() != null) {
-            petId = getArguments().getInt("petId");
-            tvPetName.setText(getArguments().getString("petName"));
-            tvPetSpecies.setText(getArguments().getString("petSpecies"));
-            tvPetBreed.setText(getArguments().getString("petBreed"));
-            tvPetAge.setText(String.format(Locale.getDefault(), "%d yr(s)", getArguments().getInt("petAge")));
-            tvPetPrice.setText(String.format(Locale.getDefault(), "$%.2f", getArguments().getDouble("petPrice")));
-
-            // Load pet image from backend
-            loadPetImage(petId);
+            petId = getArguments().getLong("petId");
+            loadPetData();
+            loadPetImage((int) petId);
         }
 
         //set button click listeners
-        btnBack.setOnClickListener(v -> {
-            //get the list fragment and pop the back stack to return to the previous view (PetFragment)
-            ListFragment listFragment = (ListFragment) getParentFragment();
-            if (listFragment != null) {
-                listFragment.getChildFragmentManager().popBackStack();
-            }
+        binding.btnBack.setOnClickListener(v -> {
+            NavHostFragment.findNavController(this).popBackStack();
         });
 
         //Make the edit button go to the pet detail view
-        btnEditPet.setOnClickListener(v -> {
-            if (getArguments() == null) return;
-
-            PetDetailFragment detailFragment = new PetDetailFragment();
-            //send the bundle to the pet detail fragment
-            detailFragment.setArguments(getArguments());
-
-            //get ListFragment to load the the detail view
-            ListFragment listFragment = (ListFragment) getParentFragment();
-            if (listFragment != null) {
-                listFragment.loadFragment(detailFragment);
-            }
+        binding.btnEditPet.setOnClickListener(v -> {
+            Bundle args = new Bundle();
+            args.putLong("petId", petId);
+            NavHostFragment.findNavController(this).navigate(R.id.nav_pet_detail, args);
         });
 
         //Make change photo button ask user to select a new photo
-        btnChangePhoto.setOnClickListener(v -> {
-            new AlertDialog.Builder(requireContext())
-                    .setTitle("Change Pet Photo")
-                    .setItems(new String[]{"Take Photo", "Choose from Gallery"}, (dialog, which) -> {
-                        if (which == 0) {
-                            // Choose Camera
-                            //Checks if the user has granted the camera permission already
-                            if (ContextCompat.checkSelfPermission(requireContext(), Manifest.permission.CAMERA) == PackageManager.PERMISSION_GRANTED) {
-                                //if the permission is already granted then launch the camera
-                                launchCamera();
-                            } else {
-                                //otherwise request the permission
-                                permissionLauncher.launch(Manifest.permission.CAMERA);
-                            }
-                        } else {
-                            Intent intent = new Intent(Intent.ACTION_PICK, MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
-                            galleryLauncher.launch(intent);
-                        }
-                    })
-                    .show();
+        binding.btnChangePhoto.setOnClickListener(v -> {
+            imagePickerHelper.showImagePickerDialog("Change Pet Photo", hasImage);
         });
 
-        return view;
+        return binding.getRoot();
     }
 
-    // Helper function to load pet image from backend
+    @Override
+    public void onDestroyView() {
+        super.onDestroyView();
+        binding = null;
+    }
+
+    /**
+     * Fetches current pet data from the backend and updates the UI.
+     */
+    private void loadPetData() {
+        viewModel.getPetById(petId).observe(getViewLifecycleOwner(), resource -> {
+            if (resource == null) return;
+            if (resource.status == Resource.Status.SUCCESS && resource.data != null) {
+                PetDTO pet = resource.data;
+                binding.tvPetName.setText(pet.getPetName());
+                binding.tvPetSpecies.setText(pet.getPetSpecies());
+                binding.tvPetBreed.setText(pet.getPetBreed());
+                binding.tvPetAge.setText(String.format(Locale.getDefault(), "%d yr(s)", pet.getPetAge()));
+                
+                if (pet.getPetPrice() != null) {
+                    binding.tvPetPrice.setText(String.format(Locale.getDefault(), "$%.2f", pet.getPetPrice()));
+                } else {
+                    binding.tvPetPrice.setText("$0.00");
+                }
+
+                // Display owner name if available, otherwise show No Owner
+                if (pet.getCustomerName() != null && !pet.getCustomerName().isEmpty()) {
+                    binding.tvPetOwner.setText(pet.getCustomerName());
+                } else {
+                    binding.tvPetOwner.setText("No Owner");
+                }
+            } else if (resource.status == Resource.Status.ERROR) {
+                Toast.makeText(getContext(), "Failed to load pet data: " + resource.message, Toast.LENGTH_SHORT).show();
+            }
+        });
+    }
+
+    /**
+     * Fetches and displays the pet\'s image from the server.
+     */
     private void loadPetImage(int petId) {
-        String imageUrl = RetrofitClient.BASE_URL + String.format(Locale.US, PetApi.PET_IMAGE_PATH, petId);
+        String imageUrl = baseUrl + String.format(Locale.US, PetApi.PET_IMAGE_PATH, petId);
+        String token = tokenManager.getToken();
 
-        Glide.with(this)
-                .load(imageUrl)
-                .diskCacheStrategy(DiskCacheStrategy.NONE)
-                .skipMemoryCache(true)
-                .placeholder(R.drawable.placeholder)
-                .error(R.drawable.placeholder)
-                .into(imgPet);
+        GlideUtils.loadImageWithToken(requireContext(), binding.imgPet, imageUrl, token, R.drawable.placeholder, new GlideUtils.ImageLoadListener() {
+            @Override
+            public void onResourceReady() {
+                hasImage = true;
+            }
+
+            @Override
+            public void onLoadFailed() {
+                hasImage = false;
+            }
+        });
     }
 
-    // Helper function to upload pet image to backend
+    /**
+     * Uploads a selected or captured image a pet photo through the ViewModel.
+     */
     private void uploadPetImage(Uri uri) {
         try {
-            File file = getFileFromUri(uri);
+            File file = FileUtils.getFileFromUri(requireContext(), uri);
             if (file == null) return;
 
             // Create RequestBody for file upload
             RequestBody requestFile = RequestBody.create(file, MediaType.parse(requireContext().getContentResolver().getType(uri)));
             MultipartBody.Part body = MultipartBody.Part.createFormData("image", file.getName(), requestFile);
 
-            // Call the backend to upload the image
-            PetApi petApi = RetrofitClient.getPetApi(requireContext());
-            petApi.uploadPetImage((long) petId, body).enqueue(new Callback<Void>() {
-                @Override
-                public void onResponse(Call<Void> call, Response<Void> response) {
-                    if (response.isSuccessful()) {
-                        Toast.makeText(requireContext(), "Pet photo updated successfully", Toast.LENGTH_SHORT).show();
-                        // Reload image after successful upload
-                        loadPetImage(petId);
+            // Use ViewModel to upload image
+            viewModel.uploadPetImage(petId, body).observe(getViewLifecycleOwner(), resource -> {
+                if (resource != null && resource.status != Resource.Status.LOADING) {
+                    if (resource.status == Resource.Status.SUCCESS) {
+                        Toast.makeText(getContext(), "Pet photo updated successfully", Toast.LENGTH_SHORT).show();
+                        loadPetImage((int) petId);
                     } else {
-                        Toast.makeText(requireContext(), "Failed to upload pet photo", Toast.LENGTH_SHORT).show();
+                        Toast.makeText(getContext(), "Upload failed: " + resource.message, Toast.LENGTH_SHORT).show();
                     }
                 }
-
-                @Override
-                public void onFailure(Call<Void> call, Throwable t) {
-                    Log.e("UPLOAD_PET_IMAGE", "Failure: " + t.getMessage());
-                    Toast.makeText(requireContext(), "Network error", Toast.LENGTH_SHORT).show();
-                }
             });
         } catch (Exception e) {
             Log.e("UPLOAD_PET_IMAGE", "Error: " + e.getMessage());
         }
     }
 
-    // Helper function to create a temporary File object from a Uri for uploading
-    private File getFileFromUri(Uri uri) {
-        try {
-            InputStream inputStream = requireContext().getContentResolver().openInputStream(uri);
-            File tempFile = new File(requireContext().getCacheDir(), "upload_pet_image.jpg");
-            FileOutputStream outputStream = new FileOutputStream(tempFile);
-            byte[] buffer = new byte[1024];
-            int length;
-            while ((length = inputStream.read(buffer)) > 0) {
-                outputStream.write(buffer, 0, length);
+    /**
+     * Sends a request to the ViewModel to remove the current pet photo.
+     */
+    private void deletePetImage() {
+        viewModel.deletePetImage(petId).observe(getViewLifecycleOwner(), resource -> {
+            if (resource != null && resource.status != Resource.Status.LOADING) {
+                if (resource.status == Resource.Status.SUCCESS) {
+                    Toast.makeText(getContext(), "Pet photo removed", Toast.LENGTH_SHORT).show();
+                    hasImage = false;
+                    binding.imgPet.setImageResource(R.drawable.placeholder);
+                } else {
+                    Toast.makeText(getContext(), "Delete failed: " + resource.message, Toast.LENGTH_SHORT).show();
+                }
             }
-            outputStream.close();
-            inputStream.close();
-            return tempFile;
-        } catch (Exception e) {
-            Log.e("FILE_UTILS", "Error creating temp file", e);
-            return null;
-        }
+        });
     }
-
-    private void launchCamera() {
-        File photoFile = new File(requireContext().getCacheDir(), "pet_photo.jpg");
-        photoUri = FileProvider.getUriForFile(requireContext(), requireContext().getPackageName() + ".fileprovider", photoFile);
-        cameraLauncher.launch(photoUri);
-    }
-}
+}

android/app/src/main/java/com/example/petstoremobile/models/Adoption.java

@@ -1,79 +0,0 @@
-package com.example.petstoremobile.models;
-
-public class Adoption {
-    private int adoptionId;
-    private String adopterName;
-    private String adopterEmail;
-    private String adopterPhone;
-    private String petName;
-    private String adoptionDate;
-    private String status;
-
-    // Constructor
-    public Adoption(int adoptionId, String adopterName, String adopterEmail, String adopterPhone, String petName, String adoptionDate, String status) {
-        this.adoptionId = adoptionId;
-        this.adopterName = adopterName;
-        this.adopterEmail = adopterEmail;
-        this.adopterPhone = adopterPhone;
-        this.petName = petName;
-        this.adoptionDate = adoptionDate;
-        this.status = status;
-    }
-
-    // Getters and setters
-    public int getAdoptionId() {
-        return adoptionId;
-    }
-
-    public void setAdoptionId(int adoptionId) {
-        this.adoptionId = adoptionId;
-    }
-
-    public String getAdopterName() {
-        return adopterName;
-    }
-
-    public void setAdopterName(String adopterName) {
-        this.adopterName = adopterName;
-    }
-
-    public String getAdopterEmail() {
-        return adopterEmail;
-    }
-
-    public void setAdopterEmail(String adopterEmail) {
-        this.adopterEmail = adopterEmail;
-    }
-
-    public String getAdopterPhone() {
-        return adopterPhone;
-    }
-
-    public void setAdopterPhone(String adopterPhone) {
-        this.adopterPhone = adopterPhone;
-    }
-
-    public String getPetName() {
-        return petName;
-    }
-
-    public void setPetName(String petName) {
-        this.petName = petName;
-    }
-
-    public String getAdoptionDate() {
-        return adoptionDate;
-    }
-
-    public void setAdoptionDate(String adoptionDate) {
-        this.adoptionDate = adoptionDate;
-    }
-
-    public String getStatus() {
-        return status;
-    }
-
-    public void setStatus(String status) {
-        this.status = status;
-    }
-}

android/app/src/main/java/com/example/petstoremobile/models/Appointment.java

@@ -1,76 +0,0 @@
-package com.example.petstoremobile.models;
-
-
-public class Appointment {
-    private int appointmentId;
-    private String customerName;
-    private String petName;
-    private String serviceType;
-    private String appointmentDate;
-    private String appointmentTime;
-    private String status;
-
-    // Constructor
-    public Appointment(int appointmentId, String customerName, String petName, String serviceType, String appointmentDate, String appointmentTime, String status) {
-        this.appointmentId = appointmentId;
-        this.customerName = customerName;
-        this.petName = petName;
-        this.serviceType = serviceType;
-        this.appointmentDate = appointmentDate;
-        this.appointmentTime = appointmentTime;
-        this.status = status;
-    }
-
-    // Getters and setters
-    public int getAppointmentId() {
-        return appointmentId;
-    }
-
-    public String getCustomerName() {
-        return customerName;
-    }
-
-    public void setCustomerName(String customerName) {
-        this.customerName = customerName;
-    }
-
-    public String getPetName() {
-        return petName;
-    }
-
-    public void setPetName(String petName) {
-        this.petName = petName;
-    }
-
-    public String getServiceType() {
-        return serviceType;
-    }
-
-    public void setServiceType(String serviceType) {
-        this.serviceType = serviceType;
-    }
-
-    public String getAppointmentDate() {
-        return appointmentDate;
-    }
-
-    public void setAppointmentDate(String appointmentDate) {
-        this.appointmentDate = appointmentDate;
-    }
-
-    public String getAppointmentTime() {
-        return appointmentTime;
-    }
-
-    public void setAppointmentTime(String appointmentTime) {
-        this.appointmentTime = appointmentTime;
-    }
-
-    public String getStatus() {
-        return status;
-    }
-
-    public void setStatus(String status) {
-        this.status = status;
-    }
-}

android/app/src/main/java/com/example/petstoremobile/models/Inventory.java

@@ -1,66 +0,0 @@
-package com.example.petstoremobile.models;
-
-
-public class Inventory {
-    private int inventoryId;
-    private String itemName;
-    private String category;
-    private int quantity;
-    private double unitPrice;
-    private String supplier;
-
-    // Constructor
-    public Inventory(int inventoryId, String itemName, String category, int quantity, double unitPrice, String supplier) {
-        this.inventoryId = inventoryId;
-        this.itemName = itemName;
-        this.category = category;
-        this.quantity = quantity;
-        this.unitPrice = unitPrice;
-        this.supplier = supplier;
-    }
-
-    // Getters and setters
-    public int getInventoryId() {
-        return inventoryId;
-    }
-
-    public String getItemName() {
-        return itemName;
-    }
-
-    public void setItemName(String itemName) {
-        this.itemName = itemName;
-    }
-
-    public String getCategory() {
-        return category;
-    }
-
-    public void setCategory(String category) {
-        this.category = category;
-    }
-
-    public int getQuantity() {
-        return quantity;
-    }
-
-    public void setQuantity(int quantity) {
-        this.quantity = quantity;
-    }
-
-    public double getUnitPrice() {
-        return unitPrice;
-    }
-
-    public void setUnitPrice(double unitPrice) {
-        this.unitPrice = unitPrice;
-    }
-
-    public String getSupplier() {
-        return supplier;
-    }
-
-    public void setSupplier(String supplier) {
-        this.supplier = supplier;
-    }
-}

android/app/src/main/java/com/example/petstoremobile/models/Message.java

@@ -7,6 +7,9 @@ public class Message {
     private String content;
     private String timestamp;
     private Boolean isRead;
+    private String attachmentUrl;
+    private String attachmentName;
+    private String attachmentType;
 
     public Message() {}
 
@@ -33,4 +36,13 @@ public class Message {
 
     public Boolean getIsRead() { return isRead; }
     public void setIsRead(Boolean isRead) { this.isRead = isRead; }
+
+    public String getAttachmentUrl() { return attachmentUrl; }
+    public void setAttachmentUrl(String attachmentUrl) { this.attachmentUrl = attachmentUrl; }
+
+    public String getAttachmentName() { return attachmentName; }
+    public void setAttachmentName(String attachmentName) { this.attachmentName = attachmentName; }
+
+    public String getAttachmentType() { return attachmentType; }
+    public void setAttachmentType(String attachmentType) { this.attachmentType = attachmentType; }
 }

android/app/src/main/java/com/example/petstoremobile/models/Product.java

@@ -1,66 +0,0 @@
-package com.example.petstoremobile.models;
-
-
-public class Product {
-    private int productId;
-    private String productName;
-    private String productDesc;
-    private String category;
-    private double productPrice;
-    private int stockQuantity;
-
-    // Constructor
-    public Product(int productId, String productName, String productDesc, String category, double productPrice, int stockQuantity) {
-        this.productId = productId;
-        this.productName = productName;
-        this.productDesc = productDesc;
-        this.category = category;
-        this.productPrice = productPrice;
-        this.stockQuantity = stockQuantity;
-    }
-
-    // Getters and setters
-    public int getProductId() {
-        return productId;
-    }
-
-    public String getProductName() {
-        return productName;
-    }
-
-    public void setProductName(String productName) {
-        this.productName = productName;
-    }
-
-    public String getProductDesc() {
-        return productDesc;
-    }
-
-    public void setProductDesc(String productDesc) {
-        this.productDesc = productDesc;
-    }
-
-    public String getCategory() {
-        return category;
-    }
-
-    public void setCategory(String category) {
-        this.category = category;
-    }
-
-    public double getProductPrice() {
-        return productPrice;
-    }
-
-    public void setProductPrice(double productPrice) {
-        this.productPrice = productPrice;
-    }
-
-    public int getStockQuantity() {
-        return stockQuantity;
-    }
-
-    public void setStockQuantity(int stockQuantity) {
-        this.stockQuantity = stockQuantity;
-    }
-}

android/app/src/main/java/com/example/petstoremobile/models/ProductSupplier.java

@@ -1,49 +0,0 @@
-package com.example.petstoremobile.models;
-
-public class ProductSupplier {
-    private int supId;
-    private int prodId;
-    private String supCompany;
-    private String prodName;
-    private double cost;
-
-    public ProductSupplier(int supId, int prodId, String supCompany, String prodName, double cost) {
-        this.supId = supId;
-        this.prodId = prodId;
-        this.supCompany = supCompany;
-        this.prodName = prodName;
-        this.cost = cost;
-    }
-
-    public int getSupId() {
-        return supId;
-    }
-
-    public int getProdId() {
-        return prodId;
-    }
-
-    public String getSupCompany() {
-        return supCompany;
-    }
-
-    public String getProdName() {
-        return prodName;
-    }
-
-    public double getCost() {
-        return cost;
-    }
-
-    public void setSupCompany(String supCompany) {
-        this.supCompany = supCompany;
-    }
-
-    public void setProdName(String prodName) {
-        this.prodName = prodName;
-    }
-
-    public void setCost(double cost) {
-        this.cost = cost;
-    }
-}

android/app/src/main/java/com/example/petstoremobile/models/PurchaseOrder.java

@@ -1,31 +0,0 @@
-package com.example.petstoremobile.models;
-
-public class PurchaseOrder {
-    private int purchaseOrderId;
-    private String supplierName;
-    private String orderDate;
-    private String status;
-
-    public PurchaseOrder(int purchaseOrderId, String supplierName, String orderDate, String status) {
-        this.purchaseOrderId = purchaseOrderId;
-        this.supplierName = supplierName;
-        this.orderDate = orderDate;
-        this.status = status;
-    }
-
-    public int getPurchaseOrderId() {
-        return purchaseOrderId;
-    }
-
-    public String getSupplierName() {
-        return supplierName;
-    }
-
-    public String getOrderDate() {
-        return orderDate;
-    }
-
-    public String getStatus() {
-        return status;
-    }
-}

android/app/src/main/java/com/example/petstoremobile/repositories/AdoptionRepository.java

@@ -0,0 +1,65 @@
+package com.example.petstoremobile.repositories;
+
+import androidx.lifecycle.LiveData;
+
+import com.example.petstoremobile.api.AdoptionApi;
+import com.example.petstoremobile.dtos.AdoptionDTO;
+import com.example.petstoremobile.dtos.BulkDeleteRequest;
+import com.example.petstoremobile.dtos.PageResponse;
+import com.example.petstoremobile.utils.Resource;
+
+import javax.inject.Inject;
+import javax.inject.Singleton;
+
+@Singleton
+public class AdoptionRepository extends BaseRepository {
+    private final AdoptionApi adoptionApi;
+
+    @Inject
+    public AdoptionRepository(AdoptionApi adoptionApi) {
+        super("AdoptionRepository");
+        this.adoptionApi = adoptionApi;
+    }
+
+    /**
+     * Retrieves a paginated list of all adoptions from the API.
+     */
+    public LiveData<Resource<PageResponse<AdoptionDTO>>> getAllAdoptions(int page, int size, String query, String status, Long storeId, String date, Long employeeId) {
+        return executeCall(adoptionApi.getAllAdoptions(page, size, query, status, storeId, date, employeeId));
+    }
+
+    /**
+     * Retrieves a specific adoption record by its ID from the API.
+     */
+    public LiveData<Resource<AdoptionDTO>> getAdoptionById(Long id) {
+        return executeCall(adoptionApi.getAdoptionById(id));
+    }
+
+    /**
+     * Sends a request to the API to create a new adoption record.
+     */
+    public LiveData<Resource<AdoptionDTO>> createAdoption(AdoptionDTO adoption) {
+        return executeCall(adoptionApi.createAdoption(adoption));
+    }
+
+    /**
+     * Sends a request to the API to update an existing adoption record by ID.
+     */
+    public LiveData<Resource<AdoptionDTO>> updateAdoption(Long id, AdoptionDTO adoption) {
+        return executeCall(adoptionApi.updateAdoption(id, adoption));
+    }
+
+    /**
+     * Sends a request to the API to delete a specific adoption record.
+     */
+    public LiveData<Resource<Void>> deleteAdoption(Long id) {
+        return executeCall(adoptionApi.deleteAdoption(id));
+    }
+
+    /**
+     * Sends a request to the API to delete multiple adoption records.
+     */
+    public LiveData<Resource<Void>> bulkDeleteAdoptions(BulkDeleteRequest request) {
+        return executeCall(adoptionApi.bulkDeleteAdoptions(request));
+    }
+}

android/app/src/main/java/com/example/petstoremobile/repositories/AppointmentRepository.java

@@ -0,0 +1,65 @@
+package com.example.petstoremobile.repositories;
+
+import androidx.lifecycle.LiveData;
+
+import com.example.petstoremobile.api.AppointmentApi;
+import com.example.petstoremobile.dtos.AppointmentDTO;
+import com.example.petstoremobile.dtos.BulkDeleteRequest;
+import com.example.petstoremobile.dtos.PageResponse;
+import com.example.petstoremobile.utils.Resource;
+
+import javax.inject.Inject;
+import javax.inject.Singleton;
+
+@Singleton
+public class AppointmentRepository extends BaseRepository {
+    private final AppointmentApi appointmentApi;
+
+    @Inject
+    public AppointmentRepository(AppointmentApi appointmentApi) {
+        super("AppointmentRepository");
+        this.appointmentApi = appointmentApi;
+    }
+
+    /**
+     * Retrieves a paginated list of all appointments from the API with filtering.
+     */
+    public LiveData<Resource<PageResponse<AppointmentDTO>>> getAllAppointments(int page, int size, String query, String status, Long storeId, String date, Long employeeId) {
+        return executeCall(appointmentApi.getAllAppointments(page, size, query, status, storeId, date, employeeId));
+    }
+
+    /**
+     * Retrieves a specific appointment by its ID from the API.
+     */
+    public LiveData<Resource<AppointmentDTO>> getAppointmentById(Long id) {
+        return executeCall(appointmentApi.getAppointmentById(id));
+    }
+
+    /**
+     * Sends a request to the API to create a new appointment record.
+     */
+    public LiveData<Resource<AppointmentDTO>> createAppointment(AppointmentDTO appointment) {
+        return executeCall(appointmentApi.createAppointment(appointment));
+    }
+
+    /**
+     * Sends a request to the API to update an existing appointment record by ID.
+     */
+    public LiveData<Resource<AppointmentDTO>> updateAppointment(Long id, AppointmentDTO appointment) {
+        return executeCall(appointmentApi.updateAppointment(id, appointment));
+    }
+
+    /**
+     * Sends a request to the API to delete a specific appointment record.
+     */
+    public LiveData<Resource<Void>> deleteAppointment(Long id) {
+        return executeCall(appointmentApi.deleteAppointment(id));
+    }
+
+    /**
+     * Sends a request to the API to delete multiple appointment records.
+     */
+    public LiveData<Resource<Void>> bulkDeleteAppointments(BulkDeleteRequest request) {
+        return executeCall(appointmentApi.bulkDeleteAppointments(request));
+    }
+}

android/app/src/main/java/com/example/petstoremobile/repositories/AuthRepository.java

@@ -0,0 +1,108 @@
+package com.example.petstoremobile.repositories;
+
+import androidx.annotation.NonNull;
+import androidx.lifecycle.LiveData;
+import androidx.lifecycle.MutableLiveData;
+
+import com.example.petstoremobile.api.auth.AuthApi;
+import com.example.petstoremobile.api.auth.TokenManager;
+import com.example.petstoremobile.dtos.AuthDTO;
+import com.example.petstoremobile.dtos.AvatarUploadResponse;
+import com.example.petstoremobile.dtos.UserDTO;
+import com.example.petstoremobile.utils.ErrorUtils;
+import com.example.petstoremobile.utils.Resource;
+
+import java.util.Map;
+
+import javax.inject.Inject;
+import javax.inject.Singleton;
+
+import okhttp3.MultipartBody;
+import retrofit2.Call;
+import retrofit2.Callback;
+import retrofit2.Response;
+
+@Singleton
+public class AuthRepository extends BaseRepository {
+    private final AuthApi authApi;
+    private final TokenManager tokenManager;
+
+    @Inject
+    public AuthRepository(AuthApi authApi, TokenManager tokenManager) {
+        super("AuthRepository");
+        this.authApi = authApi;
+        this.tokenManager = tokenManager;
+    }
+
+    /**
+     * Authenticates the user and saves login data (token, username, role) upon success.
+     */
+    public LiveData<Resource<AuthDTO.LoginResponse>> login(AuthDTO.LoginRequest loginRequest) {
+        MutableLiveData<Resource<AuthDTO.LoginResponse>> data = new MutableLiveData<>();
+        data.setValue(Resource.loading(null));
+
+        authApi.login(loginRequest).enqueue(new Callback<AuthDTO.LoginResponse>() {
+            @Override
+            public void onResponse(@NonNull Call<AuthDTO.LoginResponse> call, @NonNull Response<AuthDTO.LoginResponse> response) {
+                if (response.isSuccessful()) {
+                    AuthDTO.LoginResponse result = response.body();
+                    if (result != null && result.getToken() != null) {
+                        tokenManager.saveLoginData(result.getToken(), result.getUsername(), result.getRole());
+                        data.setValue(Resource.success(result));
+                    } else {
+                        data.setValue(Resource.error("Login failed: Invalid response", null));
+                    }
+                } else {
+                    String errorMsg = ErrorUtils.getErrorMessage(response, "Login failed");
+                    data.setValue(Resource.error(errorMsg, null));
+                }
+            }
+
+            @Override
+            public void onFailure(@NonNull Call<AuthDTO.LoginResponse> call, @NonNull Throwable t) {
+                data.setValue(Resource.error(ErrorUtils.getFailureMessage(t), null));
+            }
+        });
+
+        return data;
+    }
+
+    /**
+     * Retrieves the current user's profile information from the API.
+     */
+    public LiveData<Resource<UserDTO>> getMe() {
+        return executeCall(authApi.getMe());
+    }
+
+    /**
+     * Updates the current user's profile details.
+     */
+    public LiveData<Resource<UserDTO>> updateMe(Map<String, String> updates) {
+        return executeCall(authApi.updateMe(updates));
+    }
+
+    /**
+     * Uploads a multipart image to be used as the current user's avatar.
+     */
+    public LiveData<Resource<AvatarUploadResponse>> uploadAvatar(MultipartBody.Part avatar) {
+        return executeCall(authApi.uploadAvatar(avatar));
+    }
+
+    /**
+     * Sends a request to the API to remove the current user's avatar.
+     */
+    public LiveData<Resource<Void>> deleteAvatar() {
+        return executeCall(authApi.deleteAvatar());
+    }
+
+    /**
+     * Clears all authentication and login data from storage.
+     */
+    public void logout() {
+        tokenManager.clearLoginData();
+    }
+
+    public boolean isLoggedIn() {
+        return tokenManager.getToken() != null;
+    }
+}

android/app/src/main/java/com/example/petstoremobile/repositories/BaseRepository.java

@@ -0,0 +1,29 @@
+package com.example.petstoremobile.repositories;
+
+import androidx.lifecycle.LiveData;
+import androidx.lifecycle.MutableLiveData;
+
+import com.example.petstoremobile.utils.Resource;
+import com.example.petstoremobile.utils.RetrofitUtils;
+
+import retrofit2.Call;
+
+/**
+ * Base class for all repositories to provide common functionality for API calls.
+ */
+public abstract class BaseRepository {
+    protected final String TAG;
+
+    protected BaseRepository(String tag) {
+        this.TAG = tag;
+    }
+
+    /**
+     * Executes a Retrofit call and returns a LiveData containing the Resource.
+     */
+    protected <T> LiveData<Resource<T>> executeCall(Call<T> call) {
+        MutableLiveData<Resource<T>> data = new MutableLiveData<>();
+        RetrofitUtils.enqueue(call, data, TAG);
+        return data;
+    }
+}

android/app/src/main/java/com/example/petstoremobile/repositories/CategoryRepository.java

@@ -0,0 +1,29 @@
+package com.example.petstoremobile.repositories;
+
+import androidx.lifecycle.LiveData;
+
+import com.example.petstoremobile.api.CategoryApi;
+import com.example.petstoremobile.dtos.CategoryDTO;
+import com.example.petstoremobile.dtos.PageResponse;
+import com.example.petstoremobile.utils.Resource;
+
+import javax.inject.Inject;
+import javax.inject.Singleton;
+
+@Singleton
+public class CategoryRepository extends BaseRepository {
+    private final CategoryApi categoryApi;
+
+    @Inject
+    public CategoryRepository(CategoryApi categoryApi) {
+        super("CategoryRepository");
+        this.categoryApi = categoryApi;
+    }
+
+    /**
+     * Retrieves a paginated list of all product categories from the API.
+     */
+    public LiveData<Resource<PageResponse<CategoryDTO>>> getAllCategories(int page, int size) {
+        return executeCall(categoryApi.getAllCategories(page, size));
+    }
+}

android/app/src/main/java/com/example/petstoremobile/repositories/ChatRepository.java

@@ -0,0 +1,64 @@
+package com.example.petstoremobile.repositories;
+
+import androidx.lifecycle.LiveData;
+
+import com.example.petstoremobile.api.ChatApi;
+import com.example.petstoremobile.api.CustomerApi;
+import com.example.petstoremobile.api.MessageApi;
+import com.example.petstoremobile.dtos.ConversationDTO;
+import com.example.petstoremobile.dtos.CustomerDTO;
+import com.example.petstoremobile.dtos.MessageDTO;
+import com.example.petstoremobile.dtos.PageResponse;
+import com.example.petstoremobile.dtos.SendMessageRequest;
+import com.example.petstoremobile.utils.Resource;
+
+import java.util.List;
+
+import javax.inject.Inject;
+import javax.inject.Singleton;
+
+/**
+ * Repository for handling chat-related data operations.
+ */
+@Singleton
+public class ChatRepository extends BaseRepository {
+    private final ChatApi chatApi;
+    private final MessageApi messageApi;
+    private final CustomerApi customerApi;
+
+    @Inject
+    public ChatRepository(ChatApi chatApi, MessageApi messageApi, CustomerApi customerApi) {
+        super("ChatRepository");
+        this.chatApi = chatApi;
+        this.messageApi = messageApi;
+        this.customerApi = customerApi;
+    }
+
+    /**
+     * Retrieves all chat conversations for the current user.
+     */
+    public LiveData<Resource<List<ConversationDTO>>> getAllConversations() {
+        return executeCall(chatApi.getAllConversations());
+    }
+
+    /**
+     * Retrieves the message history for a specific conversation.
+     */
+    public LiveData<Resource<List<MessageDTO>>> getMessages(Long conversationId) {
+        return executeCall(messageApi.getMessages(conversationId));
+    }
+
+    /**
+     * Sends a plain text message to a conversation.
+     */
+    public LiveData<Resource<MessageDTO>> sendMessage(Long conversationId, SendMessageRequest request) {
+        return executeCall(messageApi.sendMessage(conversationId, request));
+    }
+
+    /**
+     * Fetches a paginated list of customers.
+     */
+    public LiveData<Resource<PageResponse<CustomerDTO>>> getAllCustomers(int page, int size) {
+        return executeCall(customerApi.getAllCustomers(page, size));
+    }
+}

android/app/src/main/java/com/example/petstoremobile/repositories/CustomerRepository.java

@@ -0,0 +1,36 @@
+package com.example.petstoremobile.repositories;
+
+import androidx.lifecycle.LiveData;
+
+import com.example.petstoremobile.api.CustomerApi;
+import com.example.petstoremobile.dtos.CustomerDTO;
+import com.example.petstoremobile.dtos.PageResponse;
+import com.example.petstoremobile.utils.Resource;
+
+import javax.inject.Inject;
+import javax.inject.Singleton;
+
+@Singleton
+public class CustomerRepository extends BaseRepository {
+    private final CustomerApi customerApi;
+
+    @Inject
+    public CustomerRepository(CustomerApi customerApi) {
+        super("CustomerRepository");
+        this.customerApi = customerApi;
+    }
+
+    /**
+     * Retrieves a paginated list of all customers from the API.
+     */
+    public LiveData<Resource<PageResponse<CustomerDTO>>> getAllCustomers(int page, int size) {
+        return executeCall(customerApi.getAllCustomers(page, size));
+    }
+
+    /**
+     * Retrieves a specific customer by their ID.
+     */
+    public LiveData<Resource<CustomerDTO>> getCustomerById(Long id) {
+        return executeCall(customerApi.getCustomerById(id));
+    }
+}

android/app/src/main/java/com/example/petstoremobile/repositories/InventoryRepository.java

@@ -0,0 +1,59 @@
+package com.example.petstoremobile.repositories;
+
+import androidx.lifecycle.LiveData;
+
+import com.example.petstoremobile.api.InventoryApi;
+import com.example.petstoremobile.dtos.BulkDeleteRequest;
+import com.example.petstoremobile.dtos.InventoryDTO;
+import com.example.petstoremobile.dtos.PageResponse;
+import com.example.petstoremobile.utils.Resource;
+
+import javax.inject.Inject;
+import javax.inject.Singleton;
+
+@Singleton
+public class InventoryRepository extends BaseRepository {
+    private final InventoryApi inventoryApi;
+
+    @Inject
+    public InventoryRepository(InventoryApi inventoryApi) {
+        super("InventoryRepository");
+        this.inventoryApi = inventoryApi;
+    }
+
+    /**
+     * Retrieves a paginated list of inventory items from the API with optional search, category, storeId and sort.
+     */
+    public LiveData<Resource<PageResponse<InventoryDTO>>> getAllInventory(String query, Long storeId, int page, int size, String sort) {
+        return executeCall(inventoryApi.getAllInventory(page, size, query, storeId, sort));
+    }
+
+    /**
+     * Retrieves a specific inventory item by its ID from the API.
+     */
+    public LiveData<Resource<InventoryDTO>> getInventoryById(Long id) {
+        return executeCall(inventoryApi.getInventoryById(id));
+    }
+
+    /**
+     * Sends a request to the API to create a new inventory record.
+     */
+    public LiveData<Resource<InventoryDTO>> createInventory(InventoryDTO request) {
+        return executeCall(inventoryApi.createInventory(request));
+    }
+
+    public LiveData<Resource<InventoryDTO>> updateInventory(Long id, InventoryDTO request) {
+        return executeCall(inventoryApi.updateInventory(id, request));
+    }
+
+    /**
+     * Sends a request to the API to delete a specific inventory record.
+     */
+    public LiveData<Resource<Void>> deleteInventory(Long id) {
+        return executeCall(inventoryApi.deleteInventory(id));
+    }
+
+    public LiveData<Resource<Void>> bulkDeleteInventory(BulkDeleteRequest request) {
+        return executeCall(inventoryApi.bulkDeleteInventory(request));
+    }
+}

android/app/src/main/java/com/example/petstoremobile/repositories/PetRepository.java

@@ -0,0 +1,81 @@
+package com.example.petstoremobile.repositories;
+
+import androidx.lifecycle.LiveData;
+
+import com.example.petstoremobile.api.PetApi;
+import com.example.petstoremobile.dtos.BulkDeleteRequest;
+import com.example.petstoremobile.dtos.PageResponse;
+import com.example.petstoremobile.dtos.PetDTO;
+import com.example.petstoremobile.utils.Resource;
+
+import javax.inject.Inject;
+import javax.inject.Singleton;
+
+import okhttp3.MultipartBody;
+
+@Singleton
+public class PetRepository extends BaseRepository {
+    private final PetApi petApi;
+
+    @Inject
+    public PetRepository(PetApi petApi) {
+        super("PetRepository");
+        this.petApi = petApi;
+    }
+
+    /**
+     * Retrieves a paginated list of pets from the API with optional filters.
+     */
+    public LiveData<Resource<PageResponse<PetDTO>>> getAllPets(int page, int size, String query, String status, String species, Long storeId, String sort) {
+        return executeCall(petApi.getAllPets(page, size, query, status, species, storeId, sort));
+    }
+
+    /**
+     * Retrieves a specific pet by its ID from the API.
+     */
+    public LiveData<Resource<PetDTO>> getPetById(Long id) {
+        return executeCall(petApi.getPetById(id));
+    }
+
+    /**
+     * Sends a request to the API to create a new pet record.
+     */
+    public LiveData<Resource<PetDTO>> createPet(PetDTO pet) {
+        return executeCall(petApi.createPet(pet));
+    }
+
+    /**
+     * Sends a request to the API to update an existing pet record.
+     */
+    public LiveData<Resource<PetDTO>> updatePet(Long id, PetDTO pet) {
+        return executeCall(petApi.updatePet(id, pet));
+    }
+
+    /**
+     * Sends a request to the API to delete a specific pet record.
+     */
+    public LiveData<Resource<Void>> deletePet(Long id) {
+        return executeCall(petApi.deletePet(id));
+    }
+
+    /**
+     * Sends a request to the API to delete multiple pet records.
+     */
+    public LiveData<Resource<Void>> bulkDeletePets(BulkDeleteRequest request) {
+        return executeCall(petApi.bulkDeletePets(request));
+    }
+
+    /**
+     * Uploads an image file for a specific pet via the API.
+     */
+    public LiveData<Resource<Void>> uploadPetImage(Long id, MultipartBody.Part image) {
+        return executeCall(petApi.uploadPetImage(id, image));
+    }
+
+    /**
+     * Sends a request to the API to delete the image of a specific pet.
+     */
+    public LiveData<Resource<Void>> deletePetImage(Long id) {
+        return executeCall(petApi.deletePetImage(id));
+    }
+}

android/app/src/main/java/com/example/petstoremobile/repositories/ProductRepository.java

@@ -0,0 +1,73 @@
+package com.example.petstoremobile.repositories;
+
+import androidx.lifecycle.LiveData;
+
+import com.example.petstoremobile.api.ProductApi;
+import com.example.petstoremobile.dtos.PageResponse;
+import com.example.petstoremobile.dtos.ProductDTO;
+import com.example.petstoremobile.utils.Resource;
+
+import javax.inject.Inject;
+import javax.inject.Singleton;
+
+import okhttp3.MultipartBody;
+
+@Singleton
+public class ProductRepository extends BaseRepository {
+    private final ProductApi productApi;
+
+    @Inject
+    public ProductRepository(ProductApi productApi) {
+        super("ProductRepository");
+        this.productApi = productApi;
+    }
+
+    /**
+     * Retrieves a paginated list of products from the API, filtered by an optional query, category and sorted.
+     */
+    public LiveData<Resource<PageResponse<ProductDTO>>> getAllProducts(String query, Long categoryId, int page, int size, String sort) {
+        return executeCall(productApi.getAllProducts(query, categoryId, page, size, sort));
+    }
+
+    /**
+     * Retrieves a specific product by its ID from the API.
+     */
+    public LiveData<Resource<ProductDTO>> getProductById(Long id) {
+        return executeCall(productApi.getProductById(id));
+    }
+
+    /**
+     * Sends a request to the API to create a new product.
+     */
+    public LiveData<Resource<ProductDTO>> createProduct(ProductDTO product) {
+        return executeCall(productApi.createProduct(product));
+    }
+
+    /**
+     * Sends a request to the API to update an existing product by ID.
+     */
+    public LiveData<Resource<ProductDTO>> updateProduct(Long id, ProductDTO product) {
+        return executeCall(productApi.updateProduct(id, product));
+    }
+
+    /**
+     * Sends a request to the API to delete a specific product.
+     */
+    public LiveData<Resource<Void>> deleteProduct(Long id) {
+        return executeCall(productApi.deleteProduct(id));
+    }
+
+    /**
+     * Uploads an image file for a specific product via the API.
+     */
+    public LiveData<Resource<Void>> uploadProductImage(Long id, MultipartBody.Part image) {
+        return executeCall(productApi.uploadProductImage(id, image));
+    }
+
+    /**
+     * Sends a request to the API to delete the image of a specific product.
+     */
+    public LiveData<Resource<Void>> deleteProductImage(Long id) {
+        return executeCall(productApi.deleteProductImage(id));
+    }
+}

android/app/src/main/java/com/example/petstoremobile/repositories/ProductSupplierRepository.java

@@ -0,0 +1,62 @@
+package com.example.petstoremobile.repositories;
+
+import androidx.lifecycle.LiveData;
+
+import com.example.petstoremobile.api.ProductSupplierApi;
+import com.example.petstoremobile.dtos.BulkDeleteRequest;
+import com.example.petstoremobile.dtos.PageResponse;
+import com.example.petstoremobile.dtos.ProductSupplierDTO;
+import com.example.petstoremobile.utils.Resource;
+
+import javax.inject.Inject;
+import javax.inject.Singleton;
+
+@Singleton
+public class ProductSupplierRepository extends BaseRepository {
+    private final ProductSupplierApi api;
+
+    @Inject
+    public ProductSupplierRepository(ProductSupplierApi api) {
+        super("ProductSupplierRepository");
+        this.api = api;
+    }
+
+    /**
+     * Retrieves a paginated list of all product-supplier relationships from the API.
+     */
+    public LiveData<Resource<PageResponse<ProductSupplierDTO>>> getAllProductSuppliers(int page, int size, String query, Long productId, Long supplierId, String sort) {
+        return executeCall(api.getAllProductSuppliers(page, size, query, productId, supplierId, sort));
+    }
+
+    /**
+     * Retrieves a single product-supplier relationship by product and supplier IDs.
+     */
+    public LiveData<Resource<ProductSupplierDTO>> getProductSupplierById(Long productId, Long supplierId) {
+        return executeCall(api.getProductSupplierById(productId, supplierId));
+    }
+
+    /**
+     * Sends a request to the API to create a new product-supplier relationship.
+     */
+    public LiveData<Resource<ProductSupplierDTO>> createProductSupplier(ProductSupplierDTO dto) {
+        return executeCall(api.createProductSupplier(dto));
+    }
+
+    /**
+     * Sends a request to the API to update an existing product-supplier relationship.
+     */
+    public LiveData<Resource<ProductSupplierDTO>> updateProductSupplier(Long productId, Long supplierId, ProductSupplierDTO dto) {
+        return executeCall(api.updateProductSupplier(productId, supplierId, dto));
+    }
+
+    /**
+     * Sends a request to the API to delete a specific product-supplier relationship.
+     */
+    public LiveData<Resource<Void>> deleteProductSupplier(Long productId, Long supplierId) {
+        return executeCall(api.deleteProductSupplier(productId, supplierId));
+    }
+
+    public LiveData<Resource<Void>> bulkDeleteProductSuppliers(BulkDeleteRequest request) {
+        return executeCall(api.bulkDeleteProductSuppliers(request));
+    }
+}

android/app/src/main/java/com/example/petstoremobile/repositories/PurchaseOrderRepository.java

@@ -0,0 +1,36 @@
+package com.example.petstoremobile.repositories;
+
+import androidx.lifecycle.LiveData;
+
+import com.example.petstoremobile.api.PurchaseOrderApi;
+import com.example.petstoremobile.dtos.PageResponse;
+import com.example.petstoremobile.dtos.PurchaseOrderDTO;
+import com.example.petstoremobile.utils.Resource;
+
+import javax.inject.Inject;
+import javax.inject.Singleton;
+
+@Singleton
+public class PurchaseOrderRepository extends BaseRepository {
+    private final PurchaseOrderApi purchaseOrderApi;
+
+    @Inject
+    public PurchaseOrderRepository(PurchaseOrderApi purchaseOrderApi) {
+        super("PurchaseOrderRepository");
+        this.purchaseOrderApi = purchaseOrderApi;
+    }
+
+    /**
+     * Retrieves a paginated list of all purchase orders from the API.
+     */
+    public LiveData<Resource<PageResponse<PurchaseOrderDTO>>> getAllPurchaseOrders(int page, int size, String query, Long storeId, String sort) {
+        return executeCall(purchaseOrderApi.getAllPurchaseOrders(page, size, query, storeId, sort));
+    }
+
+    /**
+     * Retrieves a specific purchase order by its ID from the API.
+     */
+    public LiveData<Resource<PurchaseOrderDTO>> getPurchaseOrderById(Long id) {
+        return executeCall(purchaseOrderApi.getPurchaseOrderById(id));
+    }
+}

android/app/src/main/java/com/example/petstoremobile/repositories/ServiceRepository.java

@@ -0,0 +1,65 @@
+package com.example.petstoremobile.repositories;
+
+import androidx.lifecycle.LiveData;
+
+import com.example.petstoremobile.api.ServiceApi;
+import com.example.petstoremobile.dtos.BulkDeleteRequest;
+import com.example.petstoremobile.dtos.PageResponse;
+import com.example.petstoremobile.dtos.ServiceDTO;
+import com.example.petstoremobile.utils.Resource;
+
+import javax.inject.Inject;
+import javax.inject.Singleton;
+
+@Singleton
+public class ServiceRepository extends BaseRepository {
+    private final ServiceApi serviceApi;
+
+    @Inject
+    public ServiceRepository(ServiceApi serviceApi) {
+        super("ServiceRepository");
+        this.serviceApi = serviceApi;
+    }
+
+    /**
+     * Retrieves a paginated list of all services from the API.
+     */
+    public LiveData<Resource<PageResponse<ServiceDTO>>> getAllServices(int page, int size, String query, String sort) {
+        return executeCall(serviceApi.getAllServices(page, size, query, sort));
+    }
+
+    /**
+     * Retrieves a specific service by its ID from the API.
+     */
+    public LiveData<Resource<ServiceDTO>> getServiceById(Long id) {
+        return executeCall(serviceApi.getServiceById(id));
+    }
+
+    /**
+     * Sends a request to the API to create a new service.
+     */
+    public LiveData<Resource<ServiceDTO>> createService(ServiceDTO service) {
+        return executeCall(serviceApi.createService(service));
+    }
+
+    /**
+     * Sends a request to the API to update an existing service by ID.
+     */
+    public LiveData<Resource<ServiceDTO>> updateService(Long id, ServiceDTO service) {
+        return executeCall(serviceApi.updateService(id, service));
+    }
+
+    /**
+     * Sends a request to the API to delete a specific service.
+     */
+    public LiveData<Resource<Void>> deleteService(Long id) {
+        return executeCall(serviceApi.deleteService(id));
+    }
+
+    /**
+     * Sends a request to the API to delete multiple services.
+     */
+    public LiveData<Resource<Void>> bulkDeleteServices(BulkDeleteRequest request) {
+        return executeCall(serviceApi.bulkDeleteServices(request));
+    }
+}

android/app/src/main/java/com/example/petstoremobile/repositories/StoreRepository.java

@@ -0,0 +1,29 @@
+package com.example.petstoremobile.repositories;
+
+import androidx.lifecycle.LiveData;
+
+import com.example.petstoremobile.api.StoreApi;
+import com.example.petstoremobile.dtos.PageResponse;
+import com.example.petstoremobile.dtos.StoreDTO;
+import com.example.petstoremobile.utils.Resource;
+
+import javax.inject.Inject;
+import javax.inject.Singleton;
+
+@Singleton
+public class StoreRepository extends BaseRepository {
+    private final StoreApi storeApi;
+
+    @Inject
+    public StoreRepository(StoreApi storeApi) {
+        super("StoreRepository");
+        this.storeApi = storeApi;
+    }
+
+    /**
+     * Retrieves a paginated list of all stores from the API.
+     */
+    public LiveData<Resource<PageResponse<StoreDTO>>> getAllStores(int page, int size) {
+        return executeCall(storeApi.getAllStores(page, size));
+    }
+}

android/app/src/main/java/com/example/petstoremobile/repositories/SupplierRepository.java

@@ -0,0 +1,65 @@
+package com.example.petstoremobile.repositories;
+
+import androidx.lifecycle.LiveData;
+
+import com.example.petstoremobile.api.SupplierApi;
+import com.example.petstoremobile.dtos.BulkDeleteRequest;
+import com.example.petstoremobile.dtos.PageResponse;
+import com.example.petstoremobile.dtos.SupplierDTO;
+import com.example.petstoremobile.utils.Resource;
+
+import javax.inject.Inject;
+import javax.inject.Singleton;
+
+@Singleton
+public class SupplierRepository extends BaseRepository {
+    private final SupplierApi supplierApi;
+
+    @Inject
+    public SupplierRepository(SupplierApi supplierApi) {
+        super("SupplierRepository");
+        this.supplierApi = supplierApi;
+    }
+
+    /**
+     * Retrieves a paginated list of all suppliers from the API.
+     */
+    public LiveData<Resource<PageResponse<SupplierDTO>>> getAllSuppliers(int page, int size, String query, String sort) {
+        return executeCall(supplierApi.getAllSuppliers(page, size, query, sort));
+    }
+
+    /**
+     * Retrieves a specific supplier by its ID from the API.
+     */
+    public LiveData<Resource<SupplierDTO>> getSupplierById(Long id) {
+        return executeCall(supplierApi.getSupplierById(id));
+    }
+
+    /**
+     * Sends a request to the API to create a new supplier record.
+     */
+    public LiveData<Resource<SupplierDTO>> createSupplier(SupplierDTO supplier) {
+        return executeCall(supplierApi.createSupplier(supplier));
+    }
+
+    /**
+     * Sends a request to the API to update an existing supplier record by ID.
+     */
+    public LiveData<Resource<SupplierDTO>> updateSupplier(Long id, SupplierDTO supplier) {
+        return executeCall(supplierApi.updateSupplier(id, supplier));
+    }
+
+    /**
+     * Sends a request to the API to delete a specific supplier record.
+     */
+    public LiveData<Resource<Void>> deleteSupplier(Long id) {
+        return executeCall(supplierApi.deleteSupplier(id));
+    }
+
+    /**
+     * Sends a request to the API to delete multiple supplier records.
+     */
+    public LiveData<Resource<Void>> bulkDeleteSuppliers(BulkDeleteRequest request) {
+        return executeCall(supplierApi.bulkDeleteSuppliers(request));
+    }
+}

android/app/src/main/java/com/example/petstoremobile/repositories/UserRepository.java

@@ -0,0 +1,26 @@
+package com.example.petstoremobile.repositories;
+
+import androidx.lifecycle.LiveData;
+
+import com.example.petstoremobile.api.UserApi;
+import com.example.petstoremobile.dtos.PageResponse;
+import com.example.petstoremobile.dtos.UserDTO;
+import com.example.petstoremobile.utils.Resource;
+
+import javax.inject.Inject;
+import javax.inject.Singleton;
+
+@Singleton
+public class UserRepository extends BaseRepository {
+    private final UserApi userApi;
+
+    @Inject
+    public UserRepository(UserApi userApi) {
+        super("UserRepository");
+        this.userApi = userApi;
+    }
+
+    public LiveData<Resource<PageResponse<UserDTO>>> getUsers(String role, int page, int size) {
+        return executeCall(userApi.getUsers(role, page, size));
+    }
+}

android/app/src/main/java/com/example/petstoremobile/services/ChatNotificationService.java

@@ -8,24 +8,30 @@ import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import com.example.petstoremobile.api.ChatApi;
 import com.example.petstoremobile.api.CustomerApi;
-import com.example.petstoremobile.api.RetrofitClient;
 import com.example.petstoremobile.api.auth.TokenManager;
 import com.example.petstoremobile.dtos.ConversationDTO;
 import com.example.petstoremobile.dtos.CustomerDTO;
 import com.example.petstoremobile.dtos.MessageDTO;
 import com.example.petstoremobile.dtos.PageResponse;
 import com.example.petstoremobile.utils.NotificationHelper;
+import com.example.petstoremobile.utils.RetrofitUtils;
 import com.example.petstoremobile.websocket.StompChatManager;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
+
+import javax.inject.Inject;
+import javax.inject.Named;
+
+import dagger.hilt.android.AndroidEntryPoint;
 import retrofit2.Call;
 import retrofit2.Callback;
 import retrofit2.Response;
 
 // Service to receive notifications when a new conversation is created
+@AndroidEntryPoint
 public class ChatNotificationService extends Service {
     private static final String TAG = "ChatNotificationService";
 
@@ -37,6 +43,11 @@ public class ChatNotificationService extends Service {
     private final Map<Long, String> customerIdToName = new HashMap<>();
     private Long currentUserId;
 
+    @Inject CustomerApi customerApi;
+    @Inject ChatApi chatApi;
+    @Inject TokenManager tokenManager;
+    @Inject @Named("baseUrl") String baseUrl;
+
     //When the service starts, connect to the websocket
     @Override
     public int onStartCommand(Intent intent, int flags, int startId) {
@@ -48,69 +59,42 @@ public class ChatNotificationService extends Service {
     // helper function to connect to the websocket
     private void connectWebSocket() {
         //get the token and role from the shared preferences
-        TokenManager tm = TokenManager.getInstance(this);
-        String token = tm.getToken();
-        String role = tm.getRole();
-        currentUserId = tm.getUserId();
+        String token = tokenManager.getToken();
+        String role = tokenManager.getRole();
+        currentUserId = tokenManager.getUserId();
 
         if (token != null && stompChatManager == null) {
-            //load customers to have names associated with customer ids
-            CustomerApi customerApi = RetrofitClient.getCustomerApi(this);
-            customerApi.getAllCustomers(0, 1000).enqueue(new Callback<PageResponse<CustomerDTO>>() {
-                @Override
-                public void onResponse(@NonNull Call<PageResponse<CustomerDTO>> call, @NonNull Response<PageResponse<CustomerDTO>> response) {
-                    if (response.isSuccessful() && response.body() != null) {
-                        for (CustomerDTO customer : response.body().getContent()) {
-                            customerIdToName.put(customer.getCustomerId(), customer.getFullName());
-                        }
-                    }
-                    loadConversationsAndStartStomp(token, role);
+            customerApi.getAllCustomers(0, 1000).enqueue(RetrofitUtils.createSilentCallback(TAG, result -> {
+                for (CustomerDTO customer : result.getContent()) {
+                    customerIdToName.put(customer.getCustomerId(), customer.getFullName());
                 }
-
-                @Override
-                public void onFailure(@NonNull Call<PageResponse<CustomerDTO>> call, @NonNull Throwable t) {
-                    Log.e(TAG, "Failed to load customers", t);
-                    loadConversationsAndStartStomp(token, role);
-                }
-            });
+                loadConversationsAndStartStomp(token, role);
+            }));
         }
     }
 
     private void loadConversationsAndStartStomp(String token, String role) {
         // Fetch existing conversations
-        ChatApi chatApi = RetrofitClient.getChatApi(this);
-        chatApi.getAllConversations().enqueue(new Callback<List<ConversationDTO>>() {
-            @Override
-            public void onResponse(@NonNull Call<List<ConversationDTO>> call, @NonNull Response<List<ConversationDTO>> response) {
-                if (response.isSuccessful() && response.body() != null) {
-                    for (ConversationDTO conversation : response.body()) {
-                        if (conversation.getId() != null) {
-                            knownConversationIds.add(conversation.getId());
-                            conversationToCustomerId.put(conversation.getId(), conversation.getCustomerId());
-                            // subscribe to existing conversations to get message notifications
-                            if (stompChatManager != null) {
-                                stompChatManager.subscribeToConversation(conversation.getId());
-                            }
-                        }
+        chatApi.getAllConversations().enqueue(RetrofitUtils.createSilentCallback(TAG, result -> {
+            for (ConversationDTO conversation : result) {
+                if (conversation.getId() != null) {
+                    knownConversationIds.add(conversation.getId());
+                    conversationToCustomerId.put(conversation.getId(), conversation.getCustomerId());
+                    // subscribe to existing conversations to get message notifications
+                    if (stompChatManager != null) {
+                        stompChatManager.subscribeToConversation(conversation.getId());
                     }
-                    Log.d(TAG, "Loaded " + knownConversationIds.size() + " existing conversations");
                 }
-                startStomp(token, role);
             }
-
-            @Override
-            public void onFailure(@NonNull Call<List<ConversationDTO>> call, @NonNull Throwable t) {
-                Log.e(TAG, "Failed to load existing conversations", t);
-                //tries to connect if loading fails
-                startStomp(token, role);
-            }
-        });
+            Log.d(TAG, "Loaded " + knownConversationIds.size() + " existing conversations");
+            startStomp(token, role);
+        }));
     }
 
     private void startStomp(String token, String role) {
         if (stompChatManager != null) return;
 
-        stompChatManager = new StompChatManager(token, role);
+        stompChatManager = new StompChatManager(token, role, baseUrl);
 
         // Listen for messages in existing conversations
         stompChatManager.setMessageListener(message -> {
@@ -193,20 +177,9 @@ public class ChatNotificationService extends Service {
 
     // Helper function to fetch customer name for a conversation
     private void fetchCustomerName(Long customerId) {
-        CustomerApi customerApi = RetrofitClient.getCustomerApi(this);
-        customerApi.getCustomerById(customerId).enqueue(new Callback<CustomerDTO>() {
-            @Override
-            public void onResponse(@NonNull Call<CustomerDTO> call, @NonNull Response<CustomerDTO> response) {
-                if (response.isSuccessful() && response.body() != null) {
-                    customerIdToName.put(customerId, response.body().getFullName());
-                }
-            }
-
-            @Override
-            public void onFailure(@NonNull Call<CustomerDTO> call, @NonNull Throwable t) {
-                Log.e(TAG, "Failed to fetch customer name", t);
-            }
-        });
+        customerApi.getCustomerById(customerId).enqueue(RetrofitUtils.createSilentCallback(TAG, result -> {
+            customerIdToName.put(customerId, result.getFullName());
+        }));
     }
 
     //When the service is destroyed, disconnect from the websocket

android/app/src/main/java/com/example/petstoremobile/utils/BulkDeleteHandler.java

@@ -0,0 +1,109 @@
+package com.example.petstoremobile.utils;
+
+import android.view.View;
+import android.widget.Button;
+import android.widget.TextView;
+import android.widget.Toast;
+
+import androidx.fragment.app.Fragment;
+import androidx.lifecycle.LiveData;
+
+import java.util.List;
+
+/**
+ * A helper class to handle the UI and logic for bulk deletion across different fragments.
+ * Now supports String keys to accommodate both simple and composite keys.
+ */
+public class BulkDeleteHandler {
+
+    /**
+     * Interface that adapters must implement to support bulk selection.
+     */
+    public interface SelectableAdapter {
+        List<String> getSelectedKeys();
+        void clearSelection();
+    }
+
+    /**
+     * Functional interface for the API call execution.
+     */
+    public interface BulkDeleteOperation {
+        LiveData<Resource<Void>> execute(List<String> keys);
+    }
+
+    private final Fragment fragment;
+    private final View layoutBar;
+    private final TextView tvCount;
+    private final SelectableAdapter adapter;
+    private final BulkDeleteOperation operation;
+    private final Runnable onSuccess;
+    private final String itemName;
+
+    public BulkDeleteHandler(Fragment fragment, 
+                             View layoutBar, 
+                             TextView tvCount, 
+                             Button btnDelete,
+                             SelectableAdapter adapter, 
+                             String itemName,
+                             BulkDeleteOperation operation, 
+                             Runnable onSuccess) {
+        this.fragment = fragment;
+        this.layoutBar = layoutBar;
+        this.tvCount = tvCount;
+        this.adapter = adapter;
+        this.operation = operation;
+        this.onSuccess = onSuccess;
+        this.itemName = itemName;
+
+        btnDelete.setOnClickListener(v -> confirmDelete());
+    }
+
+    /**
+     * Updates the UI when the selection count changes.
+     */
+    public void onSelectionChanged(int selectedCount) {
+        if (selectedCount > 0) {
+            layoutBar.setVisibility(View.VISIBLE);
+            tvCount.setText(selectedCount + " selected");
+        } else {
+            hideBar();
+        }
+    }
+
+    /**
+     * Hides the bulk delete bar and resets state.
+     */
+    public void hideBar() {
+        if (layoutBar != null) {
+            layoutBar.setVisibility(View.GONE);
+        }
+    }
+
+    /**
+     * Shows the confirmation dialog.
+     */
+    private void confirmDelete() {
+        List<String> keys = adapter.getSelectedKeys();
+        if (keys.isEmpty()) return;
+
+        DialogUtils.showBulkDeleteConfirmDialog(fragment.requireContext(), keys.size(), () -> performDelete(keys));
+    }
+
+    /**
+     * Executes the deletion via the provided operation.
+     */
+    private void performDelete(List<String> keys) {
+        operation.execute(keys).observe(fragment.getViewLifecycleOwner(), resource -> {
+            if (resource != null && resource.status != Resource.Status.LOADING) {
+                if (resource.status == Resource.Status.SUCCESS) {
+                    adapter.clearSelection();
+                    hideBar();
+                    onSuccess.run();
+                    Toast.makeText(fragment.getContext(), keys.size() + " " + itemName + "(s) deleted", Toast.LENGTH_SHORT).show();
+                } else {
+                    Toast.makeText(fragment.getContext(), "Delete failed: " + resource.message, Toast.LENGTH_SHORT).show();
+                }
+            }
+        });
+    }
+}

android/app/src/main/java/com/example/petstoremobile/utils/DialogUtils.java

@@ -0,0 +1,59 @@
+package com.example.petstoremobile.utils;
+
+import android.content.Context;
+import androidx.appcompat.app.AlertDialog;
+
+/**
+ * Utility class for creating and displaying common dialogs.
+ */
+public class DialogUtils {
+
+    /**
+     * Interface for handling dialog button clicks.
+     */
+    public interface DialogCallback {
+        void onConfirm();
+    }
+
+    /**
+     * Shows a confirmation dialog with "Yes" and "No" buttons.
+     */
+    public static void showConfirmDialog(Context context, String title, String message, DialogCallback callback) {
+        new AlertDialog.Builder(context)
+                .setTitle(title)
+                .setMessage(message)
+                .setPositiveButton("Yes", (dialog, which) -> callback.onConfirm())
+                .setNegativeButton("No", null)
+                .show();
+    }
+
+    /**
+     * Shows a delete confirmation dialog.
+     */
+    public static void showDeleteConfirmDialog(Context context, String itemName, DialogCallback callback) {
+        showConfirmDialog(context, "Delete " + itemName + "?", "Are you sure you want to delete this " + itemName.toLowerCase() + "? This action cannot be undone.", callback);
+    }
+
+    /**
+     * Shows a confirmation dialog with specific "Delete" and "Cancel" buttons.
+     */
+    public static void showBulkDeleteConfirmDialog(Context context, int count, DialogCallback callback) {
+        new AlertDialog.Builder(context)
+                .setTitle("Delete " + count + " item(s)?")
+                .setMessage("This cannot be undone.")
+                .setPositiveButton("Delete", (dialog, which) -> callback.onConfirm())
+                .setNegativeButton("Cancel", null)
+                .show();
+    }
+
+    /**
+     * Shows a simple information or error dialog with an "OK" button.
+     */
+    public static void showInfoDialog(Context context, String title, String message) {
+        new AlertDialog.Builder(context)
+                .setTitle(title)
+                .setMessage(message)
+                .setPositiveButton("OK", null)
+                .show();
+    }
+}

android/app/src/main/java/com/example/petstoremobile/utils/ErrorUtils.java

@@ -0,0 +1,71 @@
+package com.example.petstoremobile.utils;
+
+import android.content.Context;
+import android.util.Log;
+import android.widget.Toast;
+import com.example.petstoremobile.dtos.ErrorResponse;
+import com.google.gson.Gson;
+import java.io.IOException;
+import java.net.ConnectException;
+import java.net.SocketTimeoutException;
+import java.net.UnknownHostException;
+import retrofit2.Response;
+
+/**
+ * Utility class for handling API error responses.
+ */
+public class ErrorUtils {
+    private static final String TAG = "ErrorUtils";
+    private static final Gson gson = new Gson();
+
+    /**
+     * Shows an error message to toast based on the response.
+     */
+    public static void showErrorMessage(Context context, Response<?> response, String defaultMessage) {
+        Toast.makeText(context, getErrorMessage(response, defaultMessage), Toast.LENGTH_LONG).show();
+    }
+
+    /**
+     * Extracts a user-friendly error message from the response body or status code.
+     */
+    public static String getErrorMessage(Response<?> response, String defaultMessage) {
+        if (response == null) return defaultMessage;
+
+        try {
+            if (response.errorBody() != null) {
+                String errorJson = response.errorBody().string();
+                ErrorResponse errorResponse = gson.fromJson(errorJson, ErrorResponse.class);
+                if (errorResponse != null && errorResponse.getMessage() != null) {
+                    return errorResponse.getMessage();
+                }
+            }
+        } catch (Exception e) {
+            Log.e(TAG, "Error parsing error body", e);
+        }
+
+        // Handle specific status codes if no message was provided by the API
+        switch (response.code()) {
+            case 401: return "Unauthorized. Please login again.";
+            case 403: return "Access denied.";
+            case 404: return "Resource not found.";
+            case 500: return "Internal server error. Please try again later.";
+            case 503: return "Service unavailable. The server might be down.";
+            default: return defaultMessage + " (Code: " + response.code() + ")";
+        }
+    }
+
+    /**
+     * Converts a Throwable (from onFailure) into a user-friendly network error message.
+     */
+    public static String getFailureMessage(Throwable t) {
+        if (t instanceof UnknownHostException || t instanceof ConnectException) {
+            return "No internet connection. Please check your settings.";
+        } else if (t instanceof SocketTimeoutException) {
+            return "The connection timed out. Please try again.";
+        } else if (t instanceof IOException) {
+            return "Network error occurred. Please try again.";
+        } else {
+            return "An unexpected error occurred: " + t.getLocalizedMessage();
+        }
+    }
+}

android/app/src/main/java/com/example/petstoremobile/utils/EventDecorator.java

@@ -0,0 +1,30 @@
+package com.example.petstoremobile.utils;
+
+import com.prolificinteractive.materialcalendarview.CalendarDay;
+import com.prolificinteractive.materialcalendarview.DayViewDecorator;
+import com.prolificinteractive.materialcalendarview.DayViewFacade;
+import com.prolificinteractive.materialcalendarview.spans.DotSpan;
+
+import java.util.Collection;
+import java.util.HashSet;
+
+public class EventDecorator implements DayViewDecorator {
+
+    private final int color;
+    private final HashSet<CalendarDay> dates;
+
+    public EventDecorator(int color, Collection<CalendarDay> dates) {
+        this.color = color;
+        this.dates = new HashSet<>(dates);
+    }
+
+    @Override
+    public boolean shouldDecorate(CalendarDay day) {
+        return dates.contains(day);
+    }
+
+    @Override
+    public void decorate(DayViewFacade view) {
+        view.addSpan(new DotSpan(8, color));
+    }
+}

android/app/src/main/java/com/example/petstoremobile/utils/FileUtils.java

@@ -0,0 +1,27 @@
+package com.example.petstoremobile.utils;
+
+import android.content.Context;
+import android.net.Uri;
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.InputStream;
+
+public class FileUtils {
+    public static File getFileFromUri(Context context, Uri uri) {
+        try {
+            InputStream inputStream = context.getContentResolver().openInputStream(uri);
+            File tempFile = new File(context.getCacheDir(), "upload_image_" + System.currentTimeMillis() + ".jpg");
+            FileOutputStream outputStream = new FileOutputStream(tempFile);
+            byte[] buffer = new byte[1024];
+            int length;
+            while ((length = inputStream.read(buffer)) > 0) {
+                outputStream.write(buffer, 0, length);
+            }
+            outputStream.close();
+            inputStream.close();
+            return tempFile;
+        } catch (Exception e) {
+            return null;
+        }
+    }
+}

android/app/src/main/java/com/example/petstoremobile/utils/GlideUtils.java

@@ -0,0 +1,122 @@
+package com.example.petstoremobile.utils;
+
+import android.content.Context;
+import android.graphics.drawable.Drawable;
+import android.widget.ImageView;
+import androidx.annotation.Nullable;
+import com.bumptech.glide.Glide;
+import com.bumptech.glide.load.DataSource;
+import com.bumptech.glide.load.engine.DiskCacheStrategy;
+import com.bumptech.glide.load.engine.GlideException;
+import com.bumptech.glide.load.model.GlideUrl;
+import com.bumptech.glide.load.model.LazyHeaders;
+import com.bumptech.glide.request.RequestListener;
+import com.bumptech.glide.request.target.Target;
+import com.example.petstoremobile.R;
+
+/**
+ * Utility class for loading images using Glide with authentication tokens.
+ */
+public class GlideUtils {
+
+    /**
+     * interface to check the status of the image load.
+     */
+    public interface ImageLoadListener {
+        void onResourceReady();
+        void onLoadFailed();
+    }
+
+    /**
+     * Loads an image from a URL into an ImageView with token.
+     */
+    public static void loadImageWithToken(Context context, ImageView imageView, String url, String token, int placeholder) {
+        loadImageWithToken(context, imageView, url, token, placeholder, null);
+    }
+
+    /**
+     * Loads an image from a URL into an ImageView with token and listener.
+     */
+    public static void loadImageWithToken(Context context, ImageView imageView, String url, String token, int placeholder, ImageLoadListener listener) {
+        if (url == null) {
+            imageView.setImageResource(placeholder);
+            if (listener != null) listener.onLoadFailed();
+            return;
+        }
+
+        Object loadTarget = url;
+        if (token != null && url.startsWith("http")) {
+            loadTarget = new GlideUrl(url, new LazyHeaders.Builder()
+                    .addHeader("Authorization", "Bearer " + token)
+                    .build());
+        }
+
+        Glide.with(context)
+                .load(loadTarget)
+                .diskCacheStrategy(DiskCacheStrategy.NONE)
+                .skipMemoryCache(true)
+                .placeholder(placeholder)
+                .error(placeholder)
+                .listener(new RequestListener<Drawable>() {
+                    @Override
+                    public boolean onLoadFailed(@Nullable GlideException e, Object model, Target<Drawable> target, boolean isFirstResource) {
+                        if (listener != null) listener.onLoadFailed();
+                        return false;
+                    }
+
+                    @Override
+                    public boolean onResourceReady(Drawable resource, Object model, Target<Drawable> target, DataSource dataSource, boolean isFirstResource) {
+                        if (listener != null) listener.onResourceReady();
+                        return false;
+                    }
+                })
+                .into(imageView);
+    }
+
+    /**
+     * Loads an image from a URL into an ImageView with token and applies circle cropping for image.
+     */
+    public static void loadImageWithTokenCircle(Context context, ImageView imageView, String url, String token, int placeholder) {
+        loadImageWithTokenCircle(context, imageView, url, token, placeholder, null);
+    }
+
+    /**
+     * Loads an image from a URL into an ImageView with token, circle cropping, and listener.
+     */
+    public static void loadImageWithTokenCircle(Context context, ImageView imageView, String url, String token, int placeholder, ImageLoadListener listener) {
+        if (url == null) {
+            imageView.setImageResource(placeholder);
+            if (listener != null) listener.onLoadFailed();
+            return;
+        }
+
+        Object loadTarget = url;
+        if (token != null && url.startsWith("http")) {
+            loadTarget = new GlideUrl(url, new LazyHeaders.Builder()
+                    .addHeader("Authorization", "Bearer " + token)
+                    .build());
+        }
+
+        Glide.with(context)
+                .load(loadTarget)
+                .circleCrop()
+                .diskCacheStrategy(DiskCacheStrategy.NONE)
+                .skipMemoryCache(true)
+                .placeholder(placeholder)
+                .error(placeholder)
+                .listener(new RequestListener<Drawable>() {
+                    @Override
+                    public boolean onLoadFailed(@Nullable GlideException e, Object model, Target<Drawable> target, boolean isFirstResource) {
+                        if (listener != null) listener.onLoadFailed();
+                        return false;
+                    }
+
+                    @Override
+                    public boolean onResourceReady(Drawable resource, Object model, Target<Drawable> target, DataSource dataSource, boolean isFirstResource) {
+                        if (listener != null) listener.onResourceReady();
+                        return false;
+                    }
+                })
+                .into(imageView);
+    }
+}

android/app/src/main/java/com/example/petstoremobile/utils/ImagePickerHelper.java

@@ -0,0 +1,160 @@
+package com.example.petstoremobile.utils;
+
+import android.Manifest;
+import android.app.Activity;
+import android.content.Intent;
+import android.content.pm.PackageManager;
+import android.net.Uri;
+import android.provider.MediaStore;
+import androidx.activity.result.ActivityResultLauncher;
+import androidx.activity.result.contract.ActivityResultContracts;
+import androidx.appcompat.app.AlertDialog;
+import androidx.core.content.ContextCompat;
+import androidx.core.content.FileProvider;
+import androidx.fragment.app.Fragment;
+import java.io.File;
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Helper class to handle image picking from camera or gallery.
+ */
+public class ImagePickerHelper {
+
+    /**
+     * Listener interface to handle the results of image picking.
+     */
+    public interface ImagePickerListener {
+        /**
+         * Called when an image has been successfully selected or captured.
+         */
+        void onImagePicked(Uri uri);
+        /**
+         * Called when the user chooses to remove the existing image.
+         */
+        void onImageRemoved();
+    }
+
+    private final Fragment fragment;
+    private final ImagePickerListener listener;
+    private final ActivityResultLauncher<Intent> galleryLauncher;
+    private final ActivityResultLauncher<Uri> cameraLauncher;
+    private final ActivityResultLauncher<String> permissionLauncher;
+    private Uri photoUri;
+    private final String tempFileName;
+
+    /**
+     * Constructor for ImagePickerHelper.
+     * Registers activity launchers for gallery, camera, and permissions.
+     */
+    public ImagePickerHelper(Fragment fragment, String tempFileName, ImagePickerListener listener) {
+        this.fragment = fragment;
+        this.tempFileName = tempFileName;
+        this.listener = listener;
+
+        // Launcher to open gallery to select image
+        galleryLauncher = fragment.registerForActivityResult(
+                new ActivityResultContracts.StartActivityForResult(),
+                result -> {
+                    if (result.getResultCode() == Activity.RESULT_OK && result.getData() != null) {
+                        Uri selectedImage = result.getData().getData();
+                        if (selectedImage != null) {
+                            listener.onImagePicked(selectedImage);
+                        }
+                    }
+                }
+        );
+
+        // Launcher for camera to open and capture image
+        cameraLauncher = fragment.registerForActivityResult(
+                new ActivityResultContracts.TakePicture(),
+                success -> {
+                    if (success && photoUri != null) {
+                        listener.onImagePicked(photoUri);
+                    }
+                }
+        );
+
+        // Launcher to request camera permission
+        permissionLauncher = fragment.registerForActivityResult(
+                new ActivityResultContracts.RequestPermission(),
+                granted -> {
+                    if (granted) {
+                        launchCamera();
+                    } else {
+                        showPermissionDeniedDialog();
+                    }
+                }
+        );
+    }
+
+    /**
+     * Shows a dialog to choose between camera, gallery, and optionally remove photo.
+     */
+    public void showImagePickerDialog(String title, boolean hasImage) {
+        List<String> options = new ArrayList<>();
+        options.add("Take Photo");
+        options.add("Choose from Gallery");
+        if (hasImage) {
+            options.add("Remove Photo");
+        }
+
+        new AlertDialog.Builder(fragment.requireContext())
+                .setTitle(title)
+                .setItems(options.toArray(new String[0]), (dialog, which) -> {
+                    String selected = options.get(which);
+                    if (selected.equals("Take Photo")) {
+                        checkCameraPermission();
+                    } else if (selected.equals("Choose from Gallery")) {
+                        launchGallery();
+                    } else if (selected.equals("Remove Photo")) {
+                        listener.onImageRemoved();
+                    }
+                })
+                .show();
+    }
+
+    /**
+     * Checks if camera permission is granted and launches camera or requests permission.
+     */
+    private void checkCameraPermission() {
+        if (ContextCompat.checkSelfPermission(fragment.requireContext(), Manifest.permission.CAMERA) == PackageManager.PERMISSION_GRANTED) {
+            launchCamera();
+        } else {
+            permissionLauncher.launch(Manifest.permission.CAMERA);
+        }
+    }
+
+    /**
+     * Prepares a temporary file and launches the camera app.
+     */
+    private void launchCamera() {
+        File photoFile = new File(fragment.requireContext().getCacheDir(), tempFileName);
+        photoUri = FileProvider.getUriForFile(fragment.requireContext(), fragment.requireContext().getPackageName() + ".fileprovider", photoFile);
+        cameraLauncher.launch(photoUri);
+    }
+
+    /**
+     * Launches the gallery app to select an existing image.
+     */
+    private void launchGallery() {
+        Intent intent = new Intent(Intent.ACTION_PICK, MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
+        galleryLauncher.launch(intent);
+    }
+
+    /**
+     * Shows a dialog explaining why camera permission is needed when denied.
+     */
+    private void showPermissionDeniedDialog() {
+        new AlertDialog.Builder(fragment.requireContext())
+                .setTitle("Permission Required")
+                .setMessage("Please grant camera permission to use this feature")
+                .setPositiveButton("Open Settings", (dialog, which) -> {
+                    Intent intent = new Intent(android.provider.Settings.ACTION_APPLICATION_DETAILS_SETTINGS);
+                    intent.setData(Uri.fromParts("package", fragment.requireContext().getPackageName(), null));
+                    fragment.startActivity(intent);
+                })
+                .setNegativeButton("Cancel", null)
+                .show();
+    }
+}

android/app/src/main/java/com/example/petstoremobile/utils/InputValidator.java

@@ -1,6 +1,9 @@
 package com.example.petstoremobile.utils;
 
+import android.view.View;
 import android.widget.EditText;
+import android.widget.Spinner;
+import android.widget.TextView;
 
 public class InputValidator {
 
@@ -94,4 +97,21 @@ public class InputValidator {
         }
         return true;
     }
+
+    /**
+     * Checks if a selection has been made in a Spinner.
+     * Assumes position 0 is a placeholder like "None" or "Select".
+     */
+    public static boolean isSpinnerSelected(Spinner spinner, String fieldName) {
+        if (spinner.getSelectedItemPosition() <= 0) {
+            View selectedView = spinner.getSelectedView();
+            if (selectedView instanceof TextView) {
+                TextView tv = (TextView) selectedView;
+                tv.setError(fieldName + " is required");
+                spinner.requestFocus();
+            }
+            return false;
+        }
+        return true;
+    }
 }

android/app/src/main/java/com/example/petstoremobile/utils/Resource.java

@@ -0,0 +1,30 @@
+package com.example.petstoremobile.utils;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
+public class Resource<T> {
+    public enum Status { SUCCESS, ERROR, LOADING }
+
+    public final Status status;
+    public final T data;
+    public final String message;
+
+    private Resource(Status status, @Nullable T data, @Nullable String message) {
+        this.status = status;
+        this.data = data;
+        this.message = message;
+    }
+
+    public static <T> Resource<T> success(@Nullable T data) {
+        return new Resource<>(Status.SUCCESS, data, null);
+    }
+
+    public static <T> Resource<T> error(String msg, @Nullable T data) {
+        return new Resource<>(Status.ERROR, data, msg);
+    }
+
+    public static <T> Resource<T> loading(@Nullable T data) {
+        return new Resource<>(Status.LOADING, data, null);
+    }
+}

android/app/src/main/java/com/example/petstoremobile/utils/RetrofitUtils.java

@@ -0,0 +1,105 @@
+package com.example.petstoremobile.utils;
+
+import android.content.Context;
+import android.util.Log;
+import android.widget.Toast;
+
+import androidx.annotation.NonNull;
+import androidx.lifecycle.MutableLiveData;
+
+import retrofit2.Call;
+import retrofit2.Callback;
+import retrofit2.Response;
+
+/**
+ * Utility class for common Retrofit operations and standardized callbacks.
+ */
+public class RetrofitUtils {
+
+    /**
+     * Interface for handling successful API responses.
+     * @param <T> The type of the response body.
+     */
+    public interface SuccessCallback<T> {
+        void onSuccess(T result);
+    }
+
+    /**
+     * Enqueues a Retrofit call and updates the provided MutableLiveData with Resource states.
+     */
+    public static <T> void enqueue(@NonNull Call<T> call, @NonNull MutableLiveData<Resource<T>> data, String tag) {
+        data.setValue(Resource.loading(null));
+        call.enqueue(new Callback<T>() {
+            @Override
+            public void onResponse(@NonNull Call<T> call, @NonNull Response<T> response) {
+                if (response.isSuccessful()) {
+                    data.setValue(Resource.success(response.body()));
+                } else {
+                    String errorMsg = ErrorUtils.getErrorMessage(response, "API Error: " + response.code());
+                    Log.e(tag, errorMsg);
+                    data.setValue(Resource.error(errorMsg, null));
+                }
+            }
+
+            @Override
+            public void onFailure(@NonNull Call<T> call, @NonNull Throwable t) {
+                String errorMsg = ErrorUtils.getFailureMessage(t);
+                Log.e(tag, "Network Error: " + t.getMessage(), t);
+                data.setValue(Resource.error(errorMsg, null));
+            }
+        });
+    }
+
+    /**
+     * Creates a callback for Retrofit calls that handles errors and logging.
+     * @deprecated Use {@link #enqueue(Call, MutableLiveData, String)} for LiveData-based architecture.
+     */
+    @Deprecated
+    public static <T> Callback<T> createCallback(Context context, String tag, String successMsg, SuccessCallback<T> successCallback) {
+        return new Callback<T>() {
+            @Override
+            public void onResponse(@NonNull Call<T> call, @NonNull Response<T> response) {
+                if (response.isSuccessful()) {
+                    if (successMsg != null) {
+                        Toast.makeText(context, successMsg, Toast.LENGTH_SHORT).show();
+                    }
+                    if (successCallback != null) {
+                        successCallback.onSuccess(response.body());
+                    }
+                } else {
+                    ErrorUtils.showErrorMessage(context, response, "Operation failed");
+                    Log.e(tag, "API Error: " + response.code());
+                }
+            }
+
+            @Override
+            public void onFailure(@NonNull Call<T> call, @NonNull Throwable t) {
+                String errorMsg = ErrorUtils.getFailureMessage(t);
+                Log.e(tag, "Network Error: " + t.getMessage(), t);
+                Toast.makeText(context, errorMsg, Toast.LENGTH_SHORT).show();
+            }
+        };
+    }
+
+    /**
+     * Creates a callback that doesn't show toasts
+     */
+    @Deprecated
+    public static <T> Callback<T> createSilentCallback(String tag, SuccessCallback<T> successCallback) {
+        return new Callback<T>() {
+            @Override
+            public void onResponse(@NonNull Call<T> call, @NonNull Response<T> response) {
+                if (response.isSuccessful() && successCallback != null) {
+                    successCallback.onSuccess(response.body());
+                } else {
+                    Log.e(tag, "API Error: " + response.code());
+                }
+            }
+
+            @Override
+            public void onFailure(@NonNull Call<T> call, @NonNull Throwable t) {
+                Log.e(tag, "Network Error: " + t.getMessage(), t);
+            }
+        };
+    }
+}