Added Helper class and commented most fragments

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

@@ -38,6 +38,9 @@ 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);
@@ -71,12 +74,18 @@ public class HomeActivity extends AppCompatActivity {
         requestNotificationPermission();
     }
     
+    /**
+     * Handles new intents received while the activity is already running (like notifications).
+     */
     @Override
     protected void onNewIntent(Intent intent) {
         super.onNewIntent(intent);
         handleIntent(intent);
     }
 
+    /**
+     * 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"))) {
             Bundle args = new Bundle();
@@ -90,14 +99,17 @@ public class HomeActivity extends AppCompatActivity {
         }
     }
 
-    // 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() {
         Intent serviceIntent = new Intent(this, ChatNotificationService.class);
         startService(serviceIntent);
     }
 
-    //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) {

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

@@ -39,6 +39,9 @@ public class MainActivity extends AppCompatActivity {
     @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);
@@ -98,6 +101,9 @@ public class MainActivity extends AppCompatActivity {
         });
     }
 
+    /**
+     * 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;
@@ -129,6 +135,9 @@ public class MainActivity extends AppCompatActivity {
         });
     }
 
+    /**
+     * 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) {

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

@@ -9,13 +9,10 @@ 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.api.PetApi;
 import com.example.petstoremobile.dtos.PetDTO;
+import com.example.petstoremobile.utils.GlideUtils;
 import java.util.List;
 
 public class PetAdapter extends RecyclerView.Adapter<PetAdapter.PetViewHolder> {
@@ -93,25 +90,10 @@ public class PetAdapter extends RecyclerView.Adapter<PetAdapter.PetViewHolder> {
             holder.tvPetStatus.setBackgroundColor(Color.parseColor("#F44336"));
         }
 
-        // Load pet image using Glide with circle crop
+        // Load pet image using Glide
         if (baseUrl != null) {
             String imageUrl = baseUrl + String.format(PetApi.PET_IMAGE_PATH, pet.getPetId());
-            
+            GlideUtils.loadImageWithTokenCircle(holder.itemView.getContext(), holder.ivPetProfile, imageUrl, token, R.drawable.placeholder);
-            Object loadTarget = imageUrl;
-            if (token != null) {
-                loadTarget = new GlideUrl(imageUrl, new LazyHeaders.Builder()
-                        .addHeader("Authorization", "Bearer " + token)
-                        .build());
-            }
-
-            Glide.with(holder.itemView.getContext())
-                    .load(loadTarget)
-                    .circleCrop()
-                    .skipMemoryCache(true)
-                    .diskCacheStrategy(DiskCacheStrategy.NONE)
-                    .placeholder(R.drawable.placeholder)
-                    .error(R.drawable.placeholder)
-                    .into(holder.ivPetProfile);
         } else {
             holder.ivPetProfile.setImageResource(R.drawable.placeholder);
         }

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

@@ -6,13 +6,10 @@ 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.api.ProductApi;
 import com.example.petstoremobile.dtos.ProductDTO;
+import com.example.petstoremobile.utils.GlideUtils;
 import java.util.List;
 
 public class ProductAdapter extends RecyclerView.Adapter<ProductAdapter.ProductViewHolder> {
@@ -72,22 +69,7 @@ public class ProductAdapter extends RecyclerView.Adapter<ProductAdapter.ProductV
         // Load product image using Glide
         if (baseUrl != null) {
             String imageUrl = baseUrl + String.format(ProductApi.PRODUCT_IMAGE_PATH, p.getProdId());
-            
+            GlideUtils.loadImageWithTokenCircle(holder.itemView.getContext(), holder.ivProductImage, imageUrl, token, R.drawable.placeholder);
-            Object loadTarget = imageUrl;
-            if (token != null) {
-                loadTarget = new GlideUrl(imageUrl, new LazyHeaders.Builder()
-                        .addHeader("Authorization", "Bearer " + token)
-                        .build());
-            }
-
-            Glide.with(holder.itemView.getContext())
-                    .load(loadTarget)
-                    .circleCrop()
-                    .skipMemoryCache(true)
-                    .diskCacheStrategy(DiskCacheStrategy.NONE)
-                    .placeholder(R.drawable.placeholder)
-                    .error(R.drawable.placeholder)
-                    .into(holder.ivProductImage);
         } else {
             holder.ivProductImage.setImageResource(R.drawable.placeholder);
         }

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

@@ -88,7 +88,9 @@ public class ChatFragment extends Fragment implements ChatAdapter.OnChatClickLis
     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);
@@ -105,6 +107,9 @@ public class ChatFragment extends Fragment implements ChatAdapter.OnChatClickLis
         );
     }
 
+    /**
+     * Inflates the layout, initializes UI components, and sets up click listeners for messaging.
+     */
     @Override
     public View onCreateView(@NonNull LayoutInflater inflater,
                              ViewGroup container, Bundle savedInstanceState) {
@@ -155,7 +160,9 @@ public class ChatFragment extends Fragment implements ChatAdapter.OnChatClickLis
         return view;
     }
 
-    // Helper function to setup recycler views for chat and messages
+    /**
+     * 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);
@@ -171,7 +178,9 @@ public class ChatFragment extends Fragment implements ChatAdapter.OnChatClickLis
         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() {
         String token = tokenManager.getToken();
         currentUserId = tokenManager.getUserId();
@@ -198,7 +207,9 @@ public class ChatFragment extends Fragment implements ChatAdapter.OnChatClickLis
         loadCustomers();
     }
 
-    //Helper function to load customer names for it to be displayed on drawer menu
+    /**
+     * Fetches a list of customers from the API to display customer names for the chat list.
+     */
     private void loadCustomers() {
         customerApi.getAllCustomers(0, 100).enqueue(new Callback<PageResponse<CustomerDTO>>() {
             @Override
@@ -220,7 +231,9 @@ public class ChatFragment extends Fragment implements ChatAdapter.OnChatClickLis
         });
     }
 
-    //helper function to load conversations entities to display with customer names in drawer menu
+    /**
+     * Retrieves all conversations for the current user and populates the chat drawer.
+     */
     private void loadConversations() {
         chatApi.getAllConversations().enqueue(new Callback<List<ConversationDTO>>() {
             @Override
@@ -268,8 +281,9 @@ public class ChatFragment extends Fragment implements ChatAdapter.OnChatClickLis
         });
     }
 
-    // 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());
@@ -284,7 +298,9 @@ 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 API.
+     */
     private void loadMessageHistory(Long conversationId) {
         messageApi.getMessages(conversationId).enqueue(new Callback<List<MessageDTO>>() {
             @Override
@@ -307,7 +323,9 @@ public class ChatFragment extends Fragment implements ChatAdapter.OnChatClickLis
         });
     }
 
-    //Helper function to send a message to the chat
+    /**
+     * Sends a plain text message to the currently active conversation.
+     */
     private void sendMessage() {
         //check if a chat is selected
         if (activeConversationId == null) return;
@@ -340,14 +358,18 @@ public class ChatFragment extends Fragment implements ChatAdapter.OnChatClickLis
                 });
     }
 
-    //Helper function to open file picker when the attachment button is clicked
+    /**
+     * 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);
     }
 
-    //Helper function to show the attachment preview
+    /**
+     * Displays a preview of the selected attachment in the UI.
+     */
     private void showAttachmentPreview(Uri uri) {
         pendingAttachmentUri = uri;
         layoutAttachmentPreview.setVisibility(View.VISIBLE);
@@ -365,13 +387,17 @@ public class ChatFragment extends Fragment implements ChatAdapter.OnChatClickLis
         }
     }
 
-    //Helper function to remove the attachment
+    /**
+     * Clears the current attachment selection and hides the preview UI.
+     */
     private void removeAttachment() {
         pendingAttachmentUri = null;
         layoutAttachmentPreview.setVisibility(View.GONE);
     }
 
-    //Helper function to get the file name from the uri to display in attachment preview
+    /**
+     * Show the display name of the file from its Uri.
+     */
     private String getFileName(Uri uri) {
         String result = null;
         if (uri.getScheme().equals("content")) {
@@ -394,7 +420,9 @@ public class ChatFragment extends Fragment implements ChatAdapter.OnChatClickLis
         return result;
     }
 
-    //Helper function to send the message with attachment
+    /**
+     * Handles sending a message that includes a file attachment.
+     */
     private void sendWithAttachment(Uri uri) {
         if (activeConversationId == null) return;
 
@@ -402,7 +430,9 @@ public class ChatFragment extends Fragment implements ChatAdapter.OnChatClickLis
         Log.d(TAG, "Send with attachment happening");
     }
 
-    // When a message is received updates the chat preview
+    /**
+     * 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
@@ -420,7 +450,9 @@ public class ChatFragment extends Fragment implements ChatAdapter.OnChatClickLis
         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;
@@ -460,6 +492,9 @@ public class ChatFragment extends Fragment implements ChatAdapter.OnChatClickLis
         }
     }
 
+    /**
+     * Callback triggered when the WebSocket connection is successfully opened.
+     */
     @Override
     public void onSocketOpened() {
         if (!isAdded()) {
@@ -471,6 +506,9 @@ public class ChatFragment extends Fragment implements ChatAdapter.OnChatClickLis
         }
     }
 
+    /**
+     * Callback triggered when the WebSocket connection is closed.
+     */
     @Override
     public void onSocketClosed() {
         if (!isAdded()) {
@@ -479,6 +517,9 @@ public class ChatFragment extends Fragment implements ChatAdapter.OnChatClickLis
         loadConversations();
     }
 
+    /**
+     * Callback triggered when a WebSocket connection error occurs.
+     */
     @Override
     public void onSocketError() {
         if (!isAdded()) {
@@ -490,7 +531,9 @@ public class ChatFragment extends Fragment implements ChatAdapter.OnChatClickLis
         }
     }
 
-    // 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());
@@ -505,7 +548,9 @@ public class ChatFragment extends Fragment implements ChatAdapter.OnChatClickLis
         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(() ->
@@ -513,7 +558,9 @@ public class ChatFragment extends Fragment implements ChatAdapter.OnChatClickLis
         }
     }
 
-    // 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;
@@ -535,7 +582,9 @@ public class ChatFragment extends Fragment implements ChatAdapter.OnChatClickLis
         }
     }
 
-    //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);
@@ -558,7 +607,9 @@ public class ChatFragment extends Fragment implements ChatAdapter.OnChatClickLis
         }
     }
 
-    // When fragment is destroyed, disconnect from websocket
+    /**
+     * Disconnects the WebSocket manager when the fragment view is destroyed.
+     */
     @Override
     public void onDestroyView() {
         super.onDestroyView();

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

@@ -38,6 +38,9 @@ public class ListFragment extends Fragment {
 
     @Inject TokenManager tokenManager;
 
+    /**
+     * Inflates the fragment layout, initializes navigation drawers, and applies role-based access control.
+     */
     @Override
     public View onCreateView(LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
@@ -106,6 +109,9 @@ public class ListFragment extends Fragment {
         return view;
     }
 
+    /**
+     * Initializes the NavController for the internal fragment container.
+     */
     @Override
     public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
         super.onViewCreated(view, savedInstanceState);
@@ -116,6 +122,9 @@ public class ListFragment extends Fragment {
         }
     }
 
+    /**
+     * Navigates to a specific inner destination and closes all drawers.
+     */
     private void navigateTo(int destinationId) {
         if (innerNavController != null) {
             innerNavController.navigate(destinationId);
@@ -123,7 +132,9 @@ public class ListFragment extends Fragment {
         drawerLayout.closeDrawers();
     }
 
-    //helper function to open the drawer
+    /**
+     * Programmatically opens the navigation drawer.
+     */
     public void openDrawer() {
         drawerLayout.openDrawer(GravityCompat.START);
     }

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

@@ -1,21 +1,11 @@
 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.appcompat.app.AlertDialog;
-import androidx.core.content.ContextCompat;
-import androidx.core.content.FileProvider;
 import androidx.fragment.app.Fragment;
 
-import android.provider.MediaStore;
-import android.text.InputType;
 import android.util.Log;
 import android.view.LayoutInflater;
 import android.view.View;
@@ -26,26 +16,21 @@ 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.auth.AuthApi;
 import com.example.petstoremobile.api.auth.TokenManager;
-import com.example.petstoremobile.dtos.ErrorResponse;
 import com.example.petstoremobile.dtos.UserDTO;
 import com.example.petstoremobile.services.ChatNotificationService;
+import com.example.petstoremobile.utils.ErrorUtils;
+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.UIUtils;
 
 import java.io.File;
-import java.io.FileOutputStream;
-import java.io.InputStream;
-import java.util.ArrayList;
 import java.util.HashMap;
-import java.util.List;
 import java.util.Map;
 
 import javax.inject.Inject;
@@ -59,13 +44,15 @@ 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 UserDTO currentUser;
     private boolean hasImage = false;
 
@@ -73,71 +60,31 @@ public class ProfileFragment extends Fragment {
     @Inject TokenManager tokenManager;
     @Inject @Named("baseUrl") String baseUrl;
 
-    //Initialize the launchers for camera and gallery
+    private ImagePickerHelper imagePickerHelper;
-    private ActivityResultLauncher<Intent> galleryLauncher;
-    private ActivityResultLauncher<Uri> cameraLauncher;
-    private ActivityResultLauncher<String> permissionLauncher;
 
-    //Called when the fragment is created, sets up the launchers is set profile image
+    /**
+     * Initializes activity launchers and the ImagePickerHelper for camera and gallary.
+     */
     @Override
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
 
-        // Launcher to open gallery to select profile image
+        imagePickerHelper = new ImagePickerHelper(this, "profile_photo.jpg", new ImagePickerHelper.ImagePickerListener() {
-        galleryLauncher = registerForActivityResult(
+            @Override
-                //open gallery
+            public void onImagePicked(Uri uri) {
-                new ActivityResultContracts.StartActivityForResult(),
+                uploadAvatar(uri);
-                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);
-                    }
-                }
-        );
-
-        // 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,
                              Bundle savedInstanceState) {
@@ -160,39 +107,7 @@ public class ProfileFragment extends Fragment {
         //Set up listeners for the buttons
         //Change photo button
         btnChangePhoto.setOnClickListener(v -> {
-            List<String> options = new ArrayList<>();
+            imagePickerHelper.showImagePickerDialog("Change Profile Photo", hasImage);
-            options.add("Take Photo");
-            options.add("Choose from Gallery");
-            if (hasImage) {
-                options.add("Remove Photo");
-            }
-
-            //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(options.toArray(new String[0]), (dialog, which) -> {
-                        String selected = options.get(which);
-                        if (selected.equals("Take Photo")) {
-                            // 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 if (selected.equals("Choose from Gallery")) {
-                            // Choose Gallery
-                            Intent intent = new Intent(Intent.ACTION_PICK,
-                                    MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
-                            galleryLauncher.launch(intent);
-                        } else if (selected.equals("Remove Photo")) {
-                            deleteAvatar();
-                        }
-                    })
-                    .show();
         });
 
         //Edit email button
@@ -231,11 +146,10 @@ public class ProfileFragment extends Fragment {
             input.setText(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
+            //add canada phone number formatting to input
-            input.addTextChangedListener(new android.telephony.PhoneNumberFormattingTextWatcher("CA"));
+            UIUtils.formatPhoneInput(input);
-            input.setFilters(new android.text.InputFilter[]{new android.text.InputFilter.LengthFilter(14)});
 
 
             //Show alert dialog to user to enter new phone
@@ -256,13 +170,13 @@ public class ProfileFragment extends Fragment {
         //Logout button
         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.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);
+            android.content.Intent intent = new android.content.Intent(getActivity(), MainActivity.class);
-            intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_NEW_TASK);
+            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();
@@ -271,17 +185,9 @@ public class ProfileFragment extends Fragment {
         return view;
     }
 
-    //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() {
+     * Fetches current user profile data from the API and then updates the UI.
-        //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);
-    }
-
-    //Helper function to call the backend to get profile data and load it to the view
     private void loadProfileData() {
         authApi.getMe().enqueue(new Callback<UserDTO>() {
             @Override
@@ -300,44 +206,21 @@ public class ProfileFragment extends Fragment {
                     String avatarUrl = baseUrl + AuthApi.AVATAR_FILE_PATH;
                     String token = tokenManager.getToken();
 
-                    if (token != null) {
+                    GlideUtils.loadImageWithToken(requireContext(), imgProfile, avatarUrl, token, R.drawable.placeholder, new GlideUtils.ImageLoadListener() {
-                        // 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)
-                                .listener(new com.bumptech.glide.request.RequestListener<android.graphics.drawable.Drawable>() {
                         @Override
-                                    public boolean onLoadFailed(@androidx.annotation.Nullable com.bumptech.glide.load.engine.GlideException e, Object model, com.bumptech.glide.request.target.Target<android.graphics.drawable.Drawable> target, boolean isFirstResource) {
+                        public void onResourceReady() {
-                                        hasImage = false;
-                                        return false;
-                                    }
-
-                                    @Override
-                                    public boolean onResourceReady(android.graphics.drawable.Drawable resource, Object model, com.bumptech.glide.request.target.Target<android.graphics.drawable.Drawable> target, com.bumptech.glide.load.DataSource dataSource, boolean isFirstResource) {
                             hasImage = true;
-                                        return false;
                         }
-                                })
+
-                                .into(imgProfile);
+                        @Override
-                    } else {
+                        public void onLoadFailed() {
-                        // load placeholder image if token is null
                             hasImage = false;
-                        Glide.with(ProfileFragment.this)
-                                .load(R.drawable.placeholder)
-                                .into(imgProfile);
                         }
+                    });
                 }
                 else {
                     Log.e("onResponse: ", response.message());
-                    Toast.makeText(getContext(), "Failed to load profile: ", Toast.LENGTH_SHORT).show();
+                    ErrorUtils.showErrorMessage(getContext(), response, "Failed to load profile");
                 }
             }
 
@@ -349,10 +232,12 @@ public class ProfileFragment extends Fragment {
         });
     }
 
-    //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
@@ -369,7 +254,7 @@ public class ProfileFragment extends Fragment {
                         // Reload image after successful upload
                         loadProfileData();
                     } else {
-                        Toast.makeText(requireContext(), "Failed to upload avatar", Toast.LENGTH_SHORT).show();
+                        ErrorUtils.showErrorMessage(getContext(), response, "Failed to upload avatar");
                     }
                 }
 
@@ -384,6 +269,9 @@ public class ProfileFragment extends Fragment {
         }
     }
 
+    /**
+     * Sends a request to the API to delete the current user's avatar image.
+     */
     private void deleteAvatar() {
         authApi.deleteAvatar().enqueue(new Callback<Void>() {
             @Override
@@ -393,7 +281,7 @@ public class ProfileFragment extends Fragment {
                     hasImage = false;
                     imgProfile.setImageResource(R.drawable.placeholder);
                 } else {
-                    Toast.makeText(requireContext(), "Failed to remove avatar", Toast.LENGTH_SHORT).show();
+                    ErrorUtils.showErrorMessage(getContext(), response, "Failed to remove avatar");
                 }
             }
 
@@ -405,27 +293,9 @@ 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) {
+     * Updates a specific profile field (like email or phone) by sending a request to the API.
-        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);
-            }
-            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
     private void updateProfileField(String fieldName, String value) {
         Map<String, String> updates = new HashMap<>();
         updates.put(fieldName, value);
@@ -440,15 +310,7 @@ public class ProfileFragment extends Fragment {
                     tvProfilePhone.setText(currentUser.getPhone());
                     Toast.makeText(requireContext(), "Profile updated successfully", Toast.LENGTH_SHORT).show();
                 } else {
-                    try {
+                    ErrorUtils.showErrorMessage(getContext(), response, "Failed to update profile");
-                        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();
-                    }
                 }
             }
 

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

@@ -48,12 +48,18 @@ public class AdoptionFragment extends Fragment implements AdoptionAdapter.OnAdop
     private boolean isMonthMode = false;
     private final SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd", Locale.getDefault());
 
+    /**
+     * Initializes the fragment and its ViewModel.
+     */
     @Override
     public void onCreate(@Nullable Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         viewModel = new ViewModelProvider(this).get(AdoptionViewModel.class);
     }
 
+    /**
+     * Sets up the fragment's UI components, including RecyclerView, Search, SwipeRefresh, and Calendar.
+     */
     @Override
     public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
@@ -87,6 +93,9 @@ public class AdoptionFragment extends Fragment implements AdoptionAdapter.OnAdop
         return view;
     }
 
+    /**
+     * Toggles the calendar display between week and month modes.
+     */
     private void toggleCalendarMode() {
         isMonthMode = !isMonthMode;
         calendarView.state().edit()
@@ -94,6 +103,9 @@ public class AdoptionFragment extends Fragment implements AdoptionAdapter.OnAdop
                 .commit();
     }
 
+    /**
+     * Sets up the date selection listener for the calendar.
+     */
     private void setupCalendar() {
         calendarView.setOnDateChangedListener(new OnDateSelectedListener() {
             @Override
@@ -113,6 +125,9 @@ public class AdoptionFragment extends Fragment implements AdoptionAdapter.OnAdop
         });
     }
 
+    /**
+     * Updates the calendar decorators to highlight days with adoptions.
+     */
     private void updateCalendarDecorators() {
         HashSet<CalendarDay> datesWithAdoptions = new HashSet<>();
         for (AdoptionDTO adoption : adoptionList) {
@@ -133,6 +148,9 @@ public class AdoptionFragment extends Fragment implements AdoptionAdapter.OnAdop
         calendarView.addDecorator(new EventDecorator(Color.RED, datesWithAdoptions));
     }
 
+    /**
+     * Initializes the RecyclerView for displaying adoptions.
+     */
     private void setupRecyclerView(View view) {
         RecyclerView rv = view.findViewById(R.id.recyclerViewAdoptions);
         adapter = new AdoptionAdapter(filteredList, this);
@@ -140,6 +158,9 @@ public class AdoptionFragment extends Fragment implements AdoptionAdapter.OnAdop
         rv.setAdapter(adapter);
     }
 
+    /**
+     * Sets up the search bar for filtering
+     */
     private void setupSearch(View view) {
         etSearch = view.findViewById(R.id.etSearchAdoption);
         etSearch.addTextChangedListener(new TextWatcher() {
@@ -151,11 +172,17 @@ public class AdoptionFragment extends Fragment implements AdoptionAdapter.OnAdop
         });
     }
 
+    /**
+     * Sets up the SwipeRefreshLayout to reload adoption data.
+     */
     private void setupSwipeRefresh(View view) {
         swipeRefresh = view.findViewById(R.id.swipeRefreshAdoption);
         swipeRefresh.setOnRefreshListener(this::loadAdoptions);
     }
 
+    /**
+     * Filters the adoption list based on search query and selected calendar date.
+     */
     private void filter(String query) {
         filteredList.clear();
         String lowerQuery = query.toLowerCase();
@@ -182,7 +209,9 @@ public class AdoptionFragment extends Fragment implements AdoptionAdapter.OnAdop
         adapter.notifyDataSetChanged();
     }
 
-    // Helper function to get a list of all adoptions from the backend
+    /**
+     * Fetches the adoption list from the server through the ViewModel.
+     */
     private void loadAdoptions() {
         //Load all adoptions from the backend using viewModel
         viewModel.getAllAdoptions(0, 500).observe(getViewLifecycleOwner(), resource -> {
@@ -214,6 +243,9 @@ public class AdoptionFragment extends Fragment implements AdoptionAdapter.OnAdop
         });
     }
 
+    /**
+     * Navigates to the adoption detail screen for a specific adoption or to create a new one.
+     */
     private void openDetail(int position) {
         Bundle args = new Bundle();
 
@@ -229,6 +261,9 @@ public class AdoptionFragment extends Fragment implements AdoptionAdapter.OnAdop
         NavHostFragment.findNavController(this).navigate(R.id.nav_adoption_detail, args);
     }
 
+    /**
+     * Handles item click in the adoption list.
+     */
     @Override
     public void onAdoptionClick(int position) { openDetail(position); }
 }

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

@@ -71,6 +71,9 @@ public class AppointmentFragment extends Fragment implements AppointmentAdapter.
     private boolean isMonthMode = false;
     private final SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd", Locale.getDefault());
 
+    /**
+     * Initializes the fragment and its associated ViewModels.
+     */
     @Override
     public void onCreate(@Nullable Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
@@ -79,6 +82,9 @@ public class AppointmentFragment extends Fragment implements AppointmentAdapter.
         serviceViewModel = new ViewModelProvider(this).get(ServiceViewModel.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) {
@@ -114,7 +120,9 @@ public class AppointmentFragment extends Fragment implements AppointmentAdapter.
         return view;
     }
 
-    // Toggle Calendar Mode from week to month and other way around
+    /**
+     * Toggles the calendar between week and month display modes.
+     */
     private void toggleCalendarMode() {
         isMonthMode = !isMonthMode;
         calendarView.state().edit()
@@ -122,6 +130,9 @@ public class AppointmentFragment extends Fragment implements AppointmentAdapter.
                 .commit();
     }
 
+    /**
+     * Sets up the date selection listener for the calendar.
+     */
     private void setupCalendar() {
         calendarView.setOnDateChangedListener(new OnDateSelectedListener() {
             @Override
@@ -141,7 +152,9 @@ public class AppointmentFragment extends Fragment implements AppointmentAdapter.
         });
     }
 
-    //Set indicators for dates with appointments on the calendar
+    /**
+     * Updates calendar indicators to highlight dates that have scheduled appointments.
+     */
     private void updateCalendarDecorators() {
         HashSet<CalendarDay> datesWithAppointments = new HashSet<>();
         for (AppointmentDTO appointment : appointmentList) {
@@ -163,6 +176,9 @@ public class AppointmentFragment extends Fragment implements AppointmentAdapter.
         calendarView.addDecorator(new EventDecorator(Color.RED, datesWithAppointments));
     }
 
+    /**
+     * Configures the search bar for filtering.
+     */
     private void setupSearch(View view) {
         etSearch = view.findViewById(R.id.etSearchAppointment);
         etSearch.addTextChangedListener(new TextWatcher() {
@@ -181,6 +197,9 @@ public class AppointmentFragment extends Fragment implements AppointmentAdapter.
         });
     }
 
+    /**
+     * Filters the appointment list based on the search query and selected calendar date.
+     */
     private void filterAppointments(String query) {
         filteredList.clear();
         String lowerQuery = query.toLowerCase();
@@ -207,11 +226,17 @@ public class AppointmentFragment extends Fragment implements AppointmentAdapter.
         adapter.notifyDataSetChanged();
     }
 
+    /**
+     * Initializes the SwipeRefreshLayout to allow manual data refreshing.
+     */
     private void setupSwipeRefresh(View view) {
         swipeRefreshLayout = view.findViewById(R.id.swipeRefreshAppointment);
         swipeRefreshLayout.setOnRefreshListener(this::loadAppointmentData);
     }
 
+    /**
+     * Navigates to the appointment detail screen for editing or creating an appointment.
+     */
     private void openAppointmentDetails(int position) {
         Bundle args = new Bundle();
 
@@ -230,20 +255,32 @@ public class AppointmentFragment extends Fragment implements AppointmentAdapter.
 
         NavHostFragment.findNavController(this).navigate(R.id.nav_appointment_detail, args);
     }
+
+    /**
+     * Reloads data when an appointment is saved.
+     */
     public void onAppointmentSaved(int position, AppointmentDTO appointment) {
         loadAppointmentData();
     }
 
+    /**
+     * Reloads data when an appointment is deleted.
+     */
     public void onAppointmentDeleted(int position) {
         loadAppointmentData();
     }
 
+    /**
+     * Handles item click in the appointment list.
+     */
     @Override
     public void onAppointmentClick(int position) {
         openAppointmentDetails(position);
     }
 
-    // Helper function to get a list of all appointments from the backend
+    /**
+     * Fetches all appointment data from the server.
+     */
     private void loadAppointmentData() {
         //Load all appointments from the backend using viewModel
         appointmentViewModel.getAllAppointments(0, 500).observe(getViewLifecycleOwner(), resource -> {
@@ -275,7 +312,9 @@ public class AppointmentFragment extends Fragment implements AppointmentAdapter.
         });
     }
 
-    // Load Pets
+    /**
+     * Fetches the full list of pets from the server.
+     */
     private void loadPets() {
         petViewModel.getAllPets(0, 100).observe(getViewLifecycleOwner(), resource -> {
             if (resource != null && resource.status == Resource.Status.SUCCESS && resource.data != null) {
@@ -285,7 +324,9 @@ public class AppointmentFragment extends Fragment implements AppointmentAdapter.
         });
     }
 
-    // Load Services
+    /**
+     * Fetches the full list of services from the server.
+     */
     private void loadServices() {
         serviceViewModel.getAllServices(0, 100).observe(getViewLifecycleOwner(), resource -> {
             if (resource != null && resource.status == Resource.Status.SUCCESS && resource.data != null) {
@@ -295,6 +336,9 @@ public class AppointmentFragment extends Fragment implements AppointmentAdapter.
         });
     }
 
+    /**
+     * Get a pet's name based on its ID.
+     */
     private String getPetName(Long id) {
         for (PetDTO p : petList) {
             if (p.getPetId().equals(id)) return p.getPetName();
@@ -303,6 +347,9 @@ public class AppointmentFragment extends Fragment implements AppointmentAdapter.
         return  "";
     }
 
+    /**
+     * Get a service's name based on its ID.
+     */
     private String getServiceName(Long id) {
         for (ServiceDTO s : serviceList) {
             if (s.getServiceId().equals(id))return s.getServiceName();
@@ -310,6 +357,9 @@ public class AppointmentFragment extends Fragment implements AppointmentAdapter.
         return "";
     }
 
+    /**
+     * Initializes the RecyclerView for displaying appointments.
+     */
     private void setupRecyclerView(View view) {
         RecyclerView recyclerView = view.findViewById(R.id.recyclerViewAppointments);
         adapter = new AppointmentAdapter(filteredList, this);

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

@@ -74,12 +74,18 @@ public class InventoryFragment extends Fragment implements InventoryAdapter.OnIn
     // 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, search, and category filter.
+     */
     @Override
     public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
@@ -114,7 +120,9 @@ public class InventoryFragment extends Fragment implements InventoryAdapter.OnIn
         return view;
     }
 
-    // Categories
+    /**
+     * Fetches all product categories to populate the filter spinner.
+     */
     private void loadCategories() {
         viewModel.getAllCategories(0, 100).observe(getViewLifecycleOwner(), resource -> {
             if (resource != null && resource.status == Resource.Status.SUCCESS && resource.data != null) {
@@ -128,6 +136,9 @@ public class InventoryFragment extends Fragment implements InventoryAdapter.OnIn
         });
     }
 
+    /**
+     * Setup the category filter spinner.
+     */
     private void setupCategorySpinner() {
         // First item is always "All Categories"
         List<String> categoryNames = new ArrayList<>();
@@ -167,8 +178,9 @@ public class InventoryFragment extends Fragment implements InventoryAdapter.OnIn
         }
     }
 
-    // Search
+    /**
-
+     * Sets up the search bar for filtering.
+     */
     private void setupSearch(View view) {
         etSearch = view.findViewById(R.id.etSearchInventory);
         etSearch.addTextChangedListener(new TextWatcher() {
@@ -193,7 +205,9 @@ public class InventoryFragment extends Fragment implements InventoryAdapter.OnIn
         });
     }
 
-    // RecyclerView + infinite scroll
+    /**
+     * Initializes the RecyclerView with a layout manager, and adapter.
+     */
     private void setupRecyclerView(View view) {
         RecyclerView rv = view.findViewById(R.id.recyclerViewInventory);
         adapter = new InventoryAdapter(inventoryList, this);
@@ -218,12 +232,17 @@ public class InventoryFragment extends Fragment implements InventoryAdapter.OnIn
         });
     }
 
+    /**
+     * Sets up the SwipeRefreshLayout to reload the first page of inventory items.
+     */
     private void setupSwipeRefresh(View view) {
         swipeRefreshLayout = view.findViewById(R.id.swipeRefreshInventory);
         swipeRefreshLayout.setOnRefreshListener(() -> loadInventory(true));
     }
 
-    // Helper function to get a list of all inventory items from the backend
+    /**
+     * Fetches a page of inventory items from the API.
+     */
     private void loadInventory(boolean reset) {
         if (isLoading)
             return;
@@ -270,7 +289,9 @@ public class InventoryFragment extends Fragment implements InventoryAdapter.OnIn
         });
     }
 
-    // Combines search text and category into one query string for ?q=
+    /**
+     * Constructs a query string based on the current search text and selected category.
+     */
     private String buildQuery() {
         String q = null;
         if (!currentQuery.isEmpty() && selectedCategory != null) {
@@ -284,7 +305,9 @@ public class InventoryFragment extends Fragment implements InventoryAdapter.OnIn
         return q;
     }
 
-    // Bulk delete
+    /**
+     * Displays a confirmation dialog before performing a bulk deletion of selected items.
+     */
     private void confirmBulkDelete() {
         List<Long> ids = adapter.getSelectedIds();
         if (ids.isEmpty())
@@ -298,6 +321,9 @@ public class InventoryFragment extends Fragment implements InventoryAdapter.OnIn
                 .show();
     }
 
+    /**
+     * Executes the bulk deletion of inventory items through the ViewModel.
+     */
     private void bulkDelete(List<Long> ids) {
         viewModel.bulkDeleteInventory(ids).observe(getViewLifecycleOwner(), resource -> {
             if (resource != null && resource.status != Resource.Status.LOADING) {
@@ -313,6 +339,9 @@ public class InventoryFragment extends Fragment implements InventoryAdapter.OnIn
         });
     }
 
+    /**
+     * Hides the bulk deletion UI bar.
+     */
     private void hideBulkDeleteBar() {
         if (btnBulkDelete != null)
             btnBulkDelete.setVisibility(View.GONE);
@@ -320,7 +349,9 @@ public class InventoryFragment extends Fragment implements InventoryAdapter.OnIn
             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) {
         Bundle args = new Bundle();
 
@@ -335,12 +366,16 @@ public class InventoryFragment extends Fragment implements InventoryAdapter.OnIn
         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()) {
@@ -348,6 +383,9 @@ 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) {

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

@@ -2,7 +2,6 @@ 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;
@@ -29,7 +28,6 @@ import com.example.petstoremobile.adapters.PetAdapter;
 import com.example.petstoremobile.dtos.PetDTO;
 import com.example.petstoremobile.fragments.ListFragment;
 import com.example.petstoremobile.viewmodels.PetViewModel;
-import com.example.petstoremobile.utils.Resource;
 import com.google.android.material.floatingactionbutton.FloatingActionButton;
 
 import java.util.ArrayList;
@@ -53,12 +51,18 @@ public class PetFragment extends Fragment implements PetAdapter.OnPetClickListen
     private EditText etSearch;
     private Spinner spinnerStatus;
 
+    /**
+     * Initializes the fragment and its associated PetViewModel.
+     */
     @Override
     public void onCreate(@Nullable Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         viewModel = new ViewModelProvider(this).get(PetViewModel.class);
     }
 
+    /**
+     * Sets up the fragment's UI components, including RecyclerView, search, status filter, and swipe-to-refresh.
+     */
     @Override
     public View onCreateView(LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
@@ -72,7 +76,7 @@ public class PetFragment extends Fragment implements PetAdapter.OnPetClickListen
         setupSwipeRefresh(view);
 
         FloatingActionButton fabAddPet = view.findViewById(R.id.fabAddPet);
-        fabAddPet.setOnClickListener(v -> openPetDetails(-1));
+        fabAddPet.setOnClickListener(v -> openPetDetails());
 
         hamburger.setOnClickListener(v -> {
             Fragment parent = getParentFragment();
@@ -87,12 +91,18 @@ public class PetFragment extends Fragment implements PetAdapter.OnPetClickListen
         return view;
     }
 
+    /**
+     * Reloads pet data every time the fragment becomes visible.
+     */
     @Override
     public void onResume() {
         super.onResume();
         loadPetData();
     }
 
+    /**
+     * Configures the search bar with a for filtering.
+     */
     private void setupSearch(View view) {
         etSearch = view.findViewById(R.id.etSearchPet);
         etSearch.addTextChangedListener(new TextWatcher() {
@@ -104,6 +114,9 @@ public class PetFragment extends Fragment implements PetAdapter.OnPetClickListen
         });
     }
 
+    /**
+     * Configures the status filter spinner.
+     */
     private void setupStatusFilter(View view) {
         spinnerStatus = view.findViewById(R.id.spinnerStatus);
         String[] statuses = {"All Statuses", "Available", "Adopted"};
@@ -122,6 +135,9 @@ public class PetFragment extends Fragment implements PetAdapter.OnPetClickListen
         });
     }
 
+    /**
+     * Filters the pet list based on both the search query and the selected status.
+     */
     private void filterPets() {
         String query = etSearch.getText().toString().toLowerCase();
         String selectedStatus = spinnerStatus.getSelectedItem().toString();
@@ -143,11 +159,17 @@ public class PetFragment extends Fragment implements PetAdapter.OnPetClickListen
         adapter.notifyDataSetChanged();
     }
 
+    /**
+     * Sets up the SwipeRefreshLayout to allow manual re-fetching of pet data.
+     */
     private void setupSwipeRefresh(View view) {
         swipeRefreshLayout = view.findViewById(R.id.swipeRefreshPet);
         swipeRefreshLayout.setOnRefreshListener(this::loadPetData);
     }
 
+    /**
+     * Navigates to the pet profile screen for a specific pet.
+     */
     private void openPetProfile(int position) {
         Bundle args = new Bundle();
         PetDTO pet = filteredList.get(position);
@@ -167,16 +189,24 @@ public class PetFragment extends Fragment implements PetAdapter.OnPetClickListen
         NavHostFragment.findNavController(this).navigate(R.id.nav_pet_profile, args);
     }
 
-    private void openPetDetails(int position) {
+    /**
+     * Navigates to the pet detail screen. (Only used for adding a new pet on this screen)
+     */
+    private void openPetDetails() {
         NavHostFragment.findNavController(this).navigate(R.id.nav_pet_detail);
     }
 
+    /**
+     * Handles clicks on individual pet items in the list.
+     */
     @Override
     public void onPetClick(int position) {
         openPetProfile(position);
     }
 
-    // Helper function to get a list of all pets from the backend
+    /**
+     * Fetches all pet data from the server via the ViewModel and updates the UI.
+     */
     private void loadPetData() {
         //Load all pets from the backend using viewModel
         viewModel.getAllPets(0, 100).observe(getViewLifecycleOwner(), resource -> {
@@ -207,6 +237,9 @@ public class PetFragment extends Fragment implements PetAdapter.OnPetClickListen
         });
     }
 
+    /**
+     * Initializes the RecyclerView with a layout manager and adapter for displaying pets.
+     */
     private void setupRecyclerView(View view) {
         RecyclerView recyclerView = view.findViewById(R.id.recyclerViewPets);
         adapter = new PetAdapter(filteredList, this);

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

@@ -41,12 +41,18 @@ public class ProductFragment extends Fragment implements ProductAdapter.OnProduc
     @Inject @Named("baseUrl") String baseUrl;
     @Inject TokenManager tokenManager;
 
+    /**
+     * Initializes the fragment and its associated ProductViewModel.
+     */
     @Override
     public void onCreate(@Nullable Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         viewModel = new ViewModelProvider(this).get(ProductViewModel.class);
     }
 
+    /**
+     * Sets up the fragment's UI components, including the product list, search, and swipe-to-refresh.
+     */
     @Override
     public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
@@ -75,6 +81,9 @@ public class ProductFragment extends Fragment implements ProductAdapter.OnProduc
         return view;
     }
 
+    /**
+     * Initializes the RecyclerView with a layout manager and adapter for displaying products.
+     */
     private void setupRecyclerView(View view) {
         RecyclerView rv = view.findViewById(R.id.recyclerViewProducts);
         adapter = new ProductAdapter(filteredList, this);
@@ -84,6 +93,9 @@ public class ProductFragment extends Fragment implements ProductAdapter.OnProduc
         rv.setAdapter(adapter);
     }
 
+    /**
+     * Configures the search bar for filtering.
+     */
     private void setupSearch(View view) {
         etSearch = view.findViewById(R.id.etSearchProduct);
         etSearch.addTextChangedListener(new TextWatcher() {
@@ -95,11 +107,17 @@ public class ProductFragment extends Fragment implements ProductAdapter.OnProduc
         });
     }
 
+    /**
+     * Sets up the SwipeRefreshLayout to allow manual re-fetching of product data.
+     */
     private void setupSwipeRefresh(View view) {
         swipeRefresh = view.findViewById(R.id.swipeRefreshProduct);
         swipeRefresh.setOnRefreshListener(this::loadProducts);
     }
 
+    /**
+     * Filters the product list based on the search query across name, category, and description.
+     */
     private void filter() {
         String query = etSearch.getText().toString().toLowerCase();
 
@@ -117,7 +135,9 @@ public class ProductFragment extends Fragment implements ProductAdapter.OnProduc
         adapter.notifyDataSetChanged();
     }
 
-    // Helper function to get a list of all products from the backend
+    /**
+     * Fetches all product data from the server through the ViewModel and updates the UI.
+     */
     private void loadProducts() {
         //Load all products from the backend using viewModel
         viewModel.getAllProducts(null, 0, 100).observe(getViewLifecycleOwner(), resource -> {
@@ -148,6 +168,9 @@ public class ProductFragment extends Fragment implements ProductAdapter.OnProduc
         });
     }
 
+    /**
+     * Navigates to the product detail screen for a specific product or to add a new one.
+     */
     private void openDetail(int position) {
         Bundle args = new Bundle();
         if (position != -1) {
@@ -161,6 +184,9 @@ public class ProductFragment extends Fragment implements ProductAdapter.OnProduc
         NavHostFragment.findNavController(this).navigate(R.id.nav_product_detail, args);
     }
 
+    /**
+     * Handles item click in the product list.
+     */
     @Override
     public void onProductClick(int position) { openDetail(position); }
 }

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

@@ -35,12 +35,18 @@ public class ProductSupplierFragment extends Fragment
     private EditText etSearch;
     private ProductSupplierViewModel viewModel;
 
+    /**
+     * Initializes the fragment and its associated ProductSupplierViewModel.
+     */
     @Override
     public void onCreate(@Nullable Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         viewModel = new ViewModelProvider(this).get(ProductSupplierViewModel.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) {
@@ -68,6 +74,9 @@ public class ProductSupplierFragment extends Fragment
         return view;
     }
 
+    /**
+     * Initializes the RecyclerView with a layout manager and adapter for product-supplier data.
+     */
     private void setupRecyclerView(View view) {
         RecyclerView rv = view.findViewById(R.id.recyclerViewPS);
         adapter = new ProductSupplierAdapter(filteredList, this);
@@ -75,6 +84,9 @@ public class ProductSupplierFragment extends Fragment
         rv.setAdapter(adapter);
     }
 
+    /**
+     * Configures the search bar for filtering.
+     */
     private void setupSearch(View view) {
         etSearch = view.findViewById(R.id.etSearchPS);
         etSearch.addTextChangedListener(new TextWatcher() {
@@ -86,11 +98,17 @@ public class ProductSupplierFragment extends Fragment
         });
     }
 
+    /**
+     * Sets up the SwipeRefreshLayout to allow manual reloading of product-supplier data.
+     */
     private void setupSwipeRefresh(View view) {
         swipeRefresh = view.findViewById(R.id.swipeRefreshPS);
         swipeRefresh.setOnRefreshListener(this::loadData);
     }
 
+    /**
+     * Filters the product-supplier list based on the search query.
+     */
     private void filter(String query) {
         filteredList.clear();
         if (query.isEmpty()) {
@@ -107,7 +125,9 @@ public class ProductSupplierFragment extends Fragment
         adapter.notifyDataSetChanged();
     }
 
-    // Helper function to get a list of all product suppliers from the backend
+    /**
+     * Fetches all product-supplier data from the server through the ViewModel.
+     */
     private void loadData() {
         //Load all product suppliers from the backend using viewModel
         viewModel.getAllProductSuppliers(0, 100).observe(getViewLifecycleOwner(), resource -> {
@@ -138,6 +158,9 @@ public class ProductSupplierFragment extends Fragment
         });
     }
 
+    /**
+     * 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) {
@@ -151,6 +174,9 @@ public class ProductSupplierFragment extends Fragment
         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); }
 }

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

@@ -34,12 +34,18 @@ public class PurchaseOrderFragment extends Fragment
     private EditText etSearch;
     private PurchaseOrderViewModel viewModel;
 
+    /**
+     * Initializes the fragment and its associated PurchaseOrderViewModel.
+     */
     @Override
     public void onCreate(@Nullable Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         viewModel = new ViewModelProvider(this).get(PurchaseOrderViewModel.class);
     }
 
+    /**
+     * Sets up the fragment's UI components, including RecyclerView, search, and swipe-to-refresh.
+     */
     @Override
     public View onCreateView(LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
@@ -64,6 +70,9 @@ public class PurchaseOrderFragment extends Fragment
         return view;
     }
 
+    /**
+     * Initializes the RecyclerView with a layout manager and adapter for purchase orders.
+     */
     private void setupRecyclerView(View view) {
         RecyclerView rv = view.findViewById(R.id.recyclerViewPO);
         adapter = new PurchaseOrderAdapter(filteredList, this);
@@ -71,6 +80,9 @@ public class PurchaseOrderFragment extends Fragment
         rv.setAdapter(adapter);
     }
 
+    /**
+     * Configures the search bar for filtering.
+     */
     private void setupSearch(View view) {
         etSearch = view.findViewById(R.id.etSearchPO);
         etSearch.addTextChangedListener(new TextWatcher() {
@@ -86,11 +98,17 @@ public class PurchaseOrderFragment extends Fragment
         });
     }
 
+    /**
+     * Sets up the SwipeRefreshLayout to allow manual reloading of purchase order data.
+     */
     private void setupSwipeRefresh(View view) {
         swipeRefresh = view.findViewById(R.id.swipeRefreshPO);
         swipeRefresh.setOnRefreshListener(this::loadData);
     }
 
+    /**
+     * Filters the purchase order list based on the search query.
+     */
     private void filter(String query) {
         filteredList.clear();
         if (query.isEmpty()) {
@@ -107,7 +125,9 @@ public class PurchaseOrderFragment extends Fragment
         adapter.notifyDataSetChanged();
     }
 
-    // Helper function to get a list of all purchase orders from the backend
+    /**
+     * Fetches all purchase order data from the server through the ViewModel and updates the UI.
+     */
     private void loadData() {
         //Load all purchase orders from the backend using viewModel
         viewModel.getAllPurchaseOrders(0, 100).observe(getViewLifecycleOwner(), resource -> {
@@ -138,6 +158,9 @@ public class PurchaseOrderFragment extends Fragment
         });
     }
 
+    /**
+     * Navigates to the purchase order detail screen for a specific record.
+     */
     private void openDetail(int position) {
         Bundle args = new Bundle();
         PurchaseOrderDTO po = filteredList.get(position);
@@ -148,6 +171,9 @@ public class PurchaseOrderFragment extends Fragment
         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/ServiceFragment.java

@@ -45,13 +45,18 @@ public class ServiceFragment extends Fragment implements ServiceAdapter.OnServic
     private SwipeRefreshLayout swipeRefreshLayout;
     private EditText etSearch;
 
+    /**
+     * Initializes the fragment and its associated ServiceViewModel.
+     */
     @Override
     public void onCreate(@Nullable Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         viewModel = new ViewModelProvider(this).get(ServiceViewModel.class);
     }
 
-    //load service view
+    /**
+     * 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) {
@@ -82,6 +87,9 @@ public class ServiceFragment extends Fragment implements ServiceAdapter.OnServic
         return view;
     }
 
+    /**
+     * Configures the search bar for filtering.
+     */
     private void setupSearch(View view) {
         etSearch = view.findViewById(R.id.etSearchService);
         etSearch.addTextChangedListener(new TextWatcher() {
@@ -93,6 +101,9 @@ public class ServiceFragment extends Fragment implements ServiceAdapter.OnServic
         });
     }
 
+    /**
+     * Filters the service list based on the search query across name and description fields.
+     */
     private void filterServices(String query) {
         filteredList.clear();
         if (query.isEmpty()) {
@@ -109,12 +120,17 @@ public class ServiceFragment extends Fragment implements ServiceAdapter.OnServic
         adapter.notifyDataSetChanged();
     }
 
+    /**
+     * Sets up the SwipeRefreshLayout to allow manual reloading of service data.
+     */
     private void setupSwipeRefresh(View view) {
         swipeRefreshLayout = view.findViewById(R.id.swipeRefreshService);
         swipeRefreshLayout.setOnRefreshListener(this::loadServiceData);
     }
 
-    //Open the service detail view depending on the mode
+    /**
+     * Navigates to the service detail screen for editing an existing service or adding a new one.
+     */
     private void openServiceDetails(int position) {
         //Make a bundle to pass data to the detail fragment
         Bundle args = new Bundle();
@@ -133,13 +149,17 @@ public class ServiceFragment extends Fragment implements ServiceAdapter.OnServic
         NavHostFragment.findNavController(this).navigate(R.id.nav_service_detail, args);
     }
 
-    // Called by ServiceAdapter when a row is clicked to open the details view
+    /**
+     * Handles item click in the service list.
+     */
     @Override
     public void onServiceClick(int position) {
         openServiceDetails(position);
     }
 
-    // Helper function to get a list of all services from the backend
+    /**
+     * Fetches all service data from the server through the ViewModel and updates the UI.
+     */
     private void loadServiceData() {
         //Load all services from the backend using viewModel
         viewModel.getAllServices(0, 100).observe(getViewLifecycleOwner(), resource -> {
@@ -172,7 +192,9 @@ public class ServiceFragment extends Fragment implements ServiceAdapter.OnServic
         });
     }
 
-    //set up the recyclerview and adapter
+    /**
+     * Initializes the RecyclerView with a layout manager and adapter for services.
+     */
     private void setupRecyclerView(View view) {
         RecyclerView recyclerView = view.findViewById(R.id.recyclerViewServices);
         adapter = new ServiceAdapter(filteredList, this);

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

@@ -45,13 +45,18 @@ public class SupplierFragment extends Fragment implements SupplierAdapter.OnSupp
     private SwipeRefreshLayout swipeRefreshLayout;
     private EditText etSearch;
 
+    /**
+     * Initializes the fragment and its associated SupplierViewModel.
+     */
     @Override
     public void onCreate(@Nullable Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         viewModel = new ViewModelProvider(this).get(SupplierViewModel.class);
     }
 
-    //load supplier view
+    /**
+     * 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) {
@@ -82,6 +87,9 @@ public class SupplierFragment extends Fragment implements SupplierAdapter.OnSupp
         return view;
     }
 
+    /**
+     * Configures the search bar for filtering.
+     */
     private void setupSearch(View view) {
         etSearch = view.findViewById(R.id.etSearchSupplier);
         etSearch.addTextChangedListener(new TextWatcher() {
@@ -93,6 +101,9 @@ public class SupplierFragment extends Fragment implements SupplierAdapter.OnSupp
         });
     }
 
+    /**
+     * Filters the supplier list based on the search query across company name and contact person.
+     */
     private void filterSuppliers(String query) {
         filteredList.clear();
         if (query.isEmpty()) {
@@ -110,12 +121,17 @@ public class SupplierFragment extends Fragment implements SupplierAdapter.OnSupp
         adapter.notifyDataSetChanged();
     }
 
+    /**
+     * Sets up the SwipeRefreshLayout to allow manual reloading of supplier data.
+     */
     private void setupSwipeRefresh(View view) {
         swipeRefreshLayout = view.findViewById(R.id.swipeRefreshSupplier);
         swipeRefreshLayout.setOnRefreshListener(this::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) {
         //Make a bundle to pass data to the detail fragment
         Bundle args = new Bundle();
@@ -136,13 +152,17 @@ public class SupplierFragment extends Fragment implements SupplierAdapter.OnSupp
     }
 
 
-    // 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
+    /**
+     * Fetches all supplier data from the server through the ViewModel and updates the UI.
+     */
     private void loadSupplierData() {
         //Load all suppliers from the backend using viewModel
         viewModel.getAllSuppliers(0, 100).observe(getViewLifecycleOwner(), resource -> {
@@ -175,7 +195,9 @@ public class SupplierFragment extends Fragment implements SupplierAdapter.OnSupp
         });
     }
 
-    //set up the recyclerview and adapter
+    /**
+     * Initializes the RecyclerView with a layout manager and adapter for displaying suppliers.
+     */
     private void setupRecyclerView(View view) {
         RecyclerView recyclerView = view.findViewById(R.id.recyclerViewSuppliers);
         adapter = new SupplierAdapter(filteredList, this);

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

@@ -14,7 +14,8 @@ import com.example.petstoremobile.R;
 import com.example.petstoremobile.adapters.BlackTextArrayAdapter;
 import com.example.petstoremobile.api.*;
 import com.example.petstoremobile.dtos.*;
-import com.example.petstoremobile.fragments.ListFragment;
+import com.example.petstoremobile.utils.ErrorUtils;
+
 import java.util.*;
 
 import javax.inject.Inject;
@@ -22,6 +23,9 @@ import javax.inject.Inject;
 import dagger.hilt.android.AndroidEntryPoint;
 import retrofit2.*;
 
+/**
+ * Fragment for displaying and editing adoption request details.
+ */
 @AndroidEntryPoint
 public class AdoptionDetailFragment extends Fragment {
 
@@ -60,6 +64,9 @@ public class AdoptionDetailFragment extends Fragment {
         return view;
     }
 
+    /**
+     * Initializes UI components from the layout.
+     */
     private void initViews(View v) {
         tvMode         = v.findViewById(R.id.tvAdoptionMode);
         tvAdoptionId   = v.findViewById(R.id.tvAdoptionId);
@@ -72,11 +79,17 @@ public class AdoptionDetailFragment extends Fragment {
         btnBack        = v.findViewById(R.id.btnAdoptionBack);
     }
 
+    /**
+     * Configures the spinner for adoption status.
+     */
     private void setupSpinners() {
         spinnerStatus.setAdapter(new BlackTextArrayAdapter<>(requireContext(),
                 android.R.layout.simple_spinner_item, STATUSES));
     }
 
+    /**
+     * Configures the date picker dialog for the adoption date field.
+     */
     private void setupDatePicker() {
         etAdoptionDate.setOnClickListener(v -> {
             Calendar c = Calendar.getInstance();
@@ -89,11 +102,17 @@ public class AdoptionDetailFragment extends Fragment {
         });
     }
 
+    /**
+     * Fetches required data (pets and customers) from the backend.
+     */
     private void loadData() {
         loadPets();
         loadCustomers();
     }
 
+    /**
+     * Loads the list of pets from the API.
+     */
     private void loadPets() {
         petApi.getAllPets(0, 200)
                 .enqueue(new Callback<PageResponse<PetDTO>>() {
@@ -110,6 +129,9 @@ public class AdoptionDetailFragment extends Fragment {
                 });
     }
 
+    /**
+     * Populates the pet selection spinner.
+     */
     private void populatePetSpinner() {
         List<String> names = new ArrayList<>();
         names.add("-- Select Pet --");
@@ -125,6 +147,9 @@ public class AdoptionDetailFragment extends Fragment {
         }
     }
 
+    /**
+     * Loads the list of customers from the API.
+     */
     private void loadCustomers() {
         customerApi.getAllCustomers(0, 200)
                 .enqueue(new Callback<PageResponse<CustomerDTO>>() {
@@ -141,6 +166,9 @@ public class AdoptionDetailFragment extends Fragment {
                 });
     }
 
+    /**
+     * Populates the customer selection spinner.
+     */
     private void populateCustomerSpinner() {
         List<String> names = new ArrayList<>();
         names.add("-- Select Customer --");
@@ -157,6 +185,9 @@ public class AdoptionDetailFragment extends Fragment {
         }
     }
 
+    /**
+     * 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")) {
@@ -185,6 +216,9 @@ public class AdoptionDetailFragment extends Fragment {
         }
     }
 
+    /**
+     * Validates input and saves the adoption request to the backend.
+     */
     private void saveAdoption() {
         if (spinnerCustomer.getSelectedItemPosition() == 0) {
             Toast.makeText(getContext(), "Select a customer", Toast.LENGTH_SHORT).show(); return;
@@ -219,6 +253,9 @@ public class AdoptionDetailFragment extends Fragment {
         }
     }
 
+    /**
+     * callback for adoption save/update operations.
+     */
     private Callback<AdoptionDTO> simpleCallback(String msg) {
         return new Callback<>() {
             public void onResponse(Call<AdoptionDTO> c, Response<AdoptionDTO> r) {
@@ -227,13 +264,7 @@ public class AdoptionDetailFragment extends Fragment {
                     Toast.makeText(getContext(), msg, Toast.LENGTH_SHORT).show();
                     navigateBack();
                 } else {
-                    try {
+                    ErrorUtils.showErrorMessage(getContext(), r, "Error " + r.code());
-                        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) {
@@ -243,15 +274,16 @@ public class AdoptionDetailFragment extends Fragment {
         };
     }
 
+    /**
+     * Shows a confirmation dialog before deleting an adoption request.
+     */
     private void confirmDelete() {
         new AlertDialog.Builder(requireContext())
                 .setTitle("Delete Adoption?")
                 .setPositiveButton("Yes", (d, w) ->
                         adoptionApi.deleteAdoption(adoptionId)
                                 .enqueue(new Callback<Void>() {
-                                    public void onResponse(Call<Void> c, Response<Void> r) {
+                                    public void onResponse(Call<Void> c, Response<Void> r) { navigateBack(); }
-                                        navigateBack();
-                                    }
                                     public void onFailure(Call<Void> c, Throwable t) {
                                         Toast.makeText(getContext(), "Delete failed",
                                                 Toast.LENGTH_SHORT).show();
@@ -260,6 +292,9 @@ public class AdoptionDetailFragment extends Fragment {
                 .setNegativeButton("No", null).show();
     }
 
+    /**
+     * Navigates back to the previous fragment.
+     */
     private void navigateBack() {
         NavHostFragment.findNavController(this).popBackStack();
     }

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

@@ -14,7 +14,8 @@ import com.example.petstoremobile.R;
 import com.example.petstoremobile.adapters.BlackTextArrayAdapter;
 import com.example.petstoremobile.api.*;
 import com.example.petstoremobile.dtos.*;
-import com.example.petstoremobile.fragments.ListFragment;
+import com.example.petstoremobile.utils.ErrorUtils;
+
 import java.util.*;
 
 import javax.inject.Inject;
@@ -22,6 +23,9 @@ import javax.inject.Inject;
 import dagger.hilt.android.AndroidEntryPoint;
 import retrofit2.*;
 
+/**
+ * Fragment for displaying and editing appointment details.
+ */
 @AndroidEntryPoint
 public class AppointmentDetailFragment extends Fragment {
 
@@ -69,6 +73,9 @@ public class AppointmentDetailFragment extends Fragment {
         return view;
     }
 
+    /**
+     * Initializes UI components from the layout.
+     */
     private void initViews(View v) {
         tvMode           = v.findViewById(R.id.tvApptMode);
         tvAppointmentId  = v.findViewById(R.id.tvAppointmentId);
@@ -85,6 +92,9 @@ public class AppointmentDetailFragment extends Fragment {
         btnBack          = v.findViewById(R.id.btnApptBack);
     }
 
+    /**
+     * Configures the adapters for spinners.
+     */
     private void setupSpinners() {
         spinnerStatus.setAdapter(new BlackTextArrayAdapter<>(requireContext(),
                 android.R.layout.simple_spinner_item, STATUSES));
@@ -98,6 +108,9 @@ public class AppointmentDetailFragment extends Fragment {
                 android.R.layout.simple_spinner_item, new String[]{"00","15","30","45"}));
     }
 
+    /**
+     * Configures the date picker dialog for the appointment date field.
+     */
     private void setupDatePicker() {
         etAppointmentDate.setOnClickListener(v -> {
             Calendar c = Calendar.getInstance();
@@ -111,6 +124,9 @@ public class AppointmentDetailFragment extends Fragment {
         });
     }
 
+    /**
+     * Fetches all required data from the backend to populate the fragment.
+     */
     private void loadData() {
         loadPets();
         loadServices();
@@ -119,6 +135,9 @@ public class AppointmentDetailFragment extends Fragment {
         loadAllAppointments();
     }
 
+    /**
+     * Loads the list of pets from the API.
+     */
     private void loadPets() {
         petApi.getAllPets(0, 200)
                 .enqueue(new Callback<PageResponse<PetDTO>>() {
@@ -134,6 +153,9 @@ public class AppointmentDetailFragment extends Fragment {
                 });
     }
 
+    /**
+     * Populates the pet selection spinner.
+     */
     private void populatePetSpinner() {
         List<String> names = new ArrayList<>();
         names.add("-- Select Pet --");
@@ -149,6 +171,9 @@ public class AppointmentDetailFragment extends Fragment {
         }
     }
 
+    /**
+     * Loads the list of services from the API.
+     */
     private void loadServices() {
         serviceApi.getAllServices(0, 200)
                 .enqueue(new Callback<PageResponse<ServiceDTO>>() {
@@ -164,6 +189,9 @@ public class AppointmentDetailFragment extends Fragment {
                 });
     }
 
+    /**
+     * Populates the service selection spinner.
+     */
     private void populateServiceSpinner() {
         List<String> names = new ArrayList<>();
         names.add("-- Select Service --");
@@ -179,6 +207,9 @@ public class AppointmentDetailFragment extends Fragment {
         }
     }
 
+    /**
+     * Loads the list of customers from the API.
+     */
     private void loadCustomers() {
         customerApi.getAllCustomers(0, 200)
                 .enqueue(new Callback<PageResponse<CustomerDTO>>() {
@@ -194,6 +225,9 @@ public class AppointmentDetailFragment extends Fragment {
                 });
     }
 
+    /**
+     * Populates the customer spinner.
+     */
     private void populateCustomerSpinner() {
         List<String> names = new ArrayList<>();
         names.add("-- Select Customer --");
@@ -210,6 +244,9 @@ public class AppointmentDetailFragment extends Fragment {
         }
     }
 
+    /**
+     * Loads the list of stores from the API.
+     */
     private void loadStores() {
         storeApi.getAllStores(0, 50)
                 .enqueue(new Callback<PageResponse<StoreDTO>>() {
@@ -225,6 +262,9 @@ public class AppointmentDetailFragment extends Fragment {
                 });
     }
 
+    /**
+     * Populates the store spinner.
+     */
     private void populateStoreSpinner() {
         List<String> names = new ArrayList<>();
         names.add("-- Select Store --");
@@ -240,6 +280,9 @@ public class AppointmentDetailFragment extends Fragment {
         }
     }
 
+    /**
+     * Loads all appointments from the API.
+     */
     private void loadAllAppointments() {
         appointmentApi.getAllAppointments(0, 500)
                 .enqueue(new Callback<PageResponse<AppointmentDTO>>() {
@@ -251,6 +294,9 @@ public class AppointmentDetailFragment extends Fragment {
                 });
     }
 
+    /**
+     * 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")) {
@@ -292,6 +338,9 @@ public class AppointmentDetailFragment extends Fragment {
         }
     }
 
+    /**
+     * Validates input and saves the appointment to the backend.
+     */
     private void saveAppointment() {
         if (spinnerCustomer.getSelectedItemPosition() == 0) {
             Toast.makeText(getContext(), "Select a customer", Toast.LENGTH_SHORT).show(); return;
@@ -370,6 +419,9 @@ public class AppointmentDetailFragment extends Fragment {
         }
     }
 
+    /**
+     * callback for appointment save/update operations.
+     */
     private Callback<AppointmentDTO> simpleCallback(String msg) {
         return new Callback<>() {
             public void onResponse(Call<AppointmentDTO> c, Response<AppointmentDTO> r) {
@@ -387,22 +439,12 @@ public class AppointmentDetailFragment extends Fragment {
                             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.");
+                            ErrorUtils.showErrorMessage(getContext(), r, "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.");
@@ -417,6 +459,9 @@ public class AppointmentDetailFragment extends Fragment {
         };
     }
 
+    /**
+     * Shows a specialized dialog when a time slot is not available.
+     */
     private void showNoAvailabilityDialog() {
         new AlertDialog.Builder(requireContext())
                 .setTitle("No Availability")
@@ -427,6 +472,9 @@ public class AppointmentDetailFragment extends Fragment {
                 .show();
     }
 
+    /**
+     * Shows a generic error dialog with a title and message.
+     */
     private void showErrorDialog(String title, String message) {
         new AlertDialog.Builder(requireContext())
                 .setTitle(title)
@@ -434,6 +482,10 @@ public class AppointmentDetailFragment extends Fragment {
                 .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?")
@@ -448,6 +500,9 @@ public class AppointmentDetailFragment extends Fragment {
                 .setNegativeButton("No", null).show();
     }
 
+    /**
+     * Navigates back to the previous screen.
+     */
     private void navigateBack() {
         NavHostFragment.findNavController(this).popBackStack();
     }

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

@@ -26,8 +26,8 @@ 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.utils.ErrorUtils;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -39,6 +39,9 @@ import retrofit2.Call;
 import retrofit2.Callback;
 import retrofit2.Response;
 
+/**
+ * Fragment for displaying and editing inventory item details.
+ */
 @AndroidEntryPoint
 public class InventoryDetailFragment extends Fragment {
 
@@ -65,6 +68,9 @@ public class InventoryDetailFragment extends Fragment {
     private final List<ProductDTO> productSuggestions = new ArrayList<>();
     private ArrayAdapter<String> dropdownAdapter;
 
+    /**
+     * Sets the parent inventory fragment to notify of changes.
+     */
     public void setInventoryFragment(InventoryFragment fragment) {
         this.inventoryFragment = fragment;
     }
@@ -85,6 +91,9 @@ public class InventoryDetailFragment extends Fragment {
         return view;
     }
 
+    /**
+     * get the layout view and set adapter.
+     */
     private void initViews(View view) {
         tvMode = view.findViewById(R.id.tvInventoryMode);
         tvInventoryId = view.findViewById(R.id.tvInventoryId);
@@ -102,7 +111,9 @@ public class InventoryDetailFragment extends Fragment {
         etProductSearch.setThreshold(1); // start showing after 1 character
     }
 
-    // Product search dropdown
+    /**
+     * setup the product search dropdown.
+     */
     private void setupProductSearch() {
         etProductSearch.addTextChangedListener(new TextWatcher() {
             @Override
@@ -143,6 +154,9 @@ public class InventoryDetailFragment extends Fragment {
         });
     }
 
+    /**
+     * Searches for products matching the query from the backend.
+     */
     private void searchProducts(String query) {
         productApi.getAllProducts(query, 0, 20).enqueue(new Callback<PageResponse<ProductDTO>>() {
             @Override
@@ -172,8 +186,9 @@ public class InventoryDetailFragment extends Fragment {
         });
     }
 
-    // Arguments (edit mode)
+    /**
-
+     * arguments to set up edit or add mode.
+     */
     private void handleArguments() {
         Bundle args = getArguments();
         if (args != null && args.containsKey("inventoryId")) {
@@ -214,7 +229,9 @@ public class InventoryDetailFragment extends Fragment {
         }
     }
 
-    // Save
+    /**
+     * Saves the current inventory item details to the backend.
+     */
     private void saveInventory() {
         if (selectedProduct == null) {
             etProductSearch.setError("Please select a product from the list");
@@ -255,7 +272,7 @@ public class InventoryDetailFragment extends Fragment {
                         Toast.makeText(getContext(), "Inventory updated", Toast.LENGTH_SHORT).show();
                         notifyParentAndGoBack();
                     } else {
-                        Toast.makeText(getContext(), "Update failed: " + response.code(), Toast.LENGTH_SHORT).show();
+                        ErrorUtils.showErrorMessage(getContext(), response, "Update failed");
                     }
                 }
 
@@ -274,7 +291,7 @@ public class InventoryDetailFragment extends Fragment {
                         Toast.makeText(getContext(), "Inventory created", Toast.LENGTH_SHORT).show();
                         notifyParentAndGoBack();
                     } else {
-                        Toast.makeText(getContext(), "Create failed: " + response.code(), Toast.LENGTH_SHORT).show();
+                        ErrorUtils.showErrorMessage(getContext(), response, "Create failed");
                     }
                 }
 
@@ -287,7 +304,9 @@ public class InventoryDetailFragment extends Fragment {
         }
     }
 
-    // Delete
+    /**
+     * Shows a confirmation dialog before deleting an inventory item.
+     */
     private void confirmDelete() {
         new AlertDialog.Builder(requireContext())
                 .setTitle("Delete inventory item?")
@@ -297,6 +316,9 @@ 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>() {
@@ -307,7 +329,7 @@ public class InventoryDetailFragment extends Fragment {
                     Toast.makeText(getContext(), "Inventory deleted", Toast.LENGTH_SHORT).show();
                     notifyParentAndGoBack();
                 } else {
-                    Toast.makeText(getContext(), "Delete failed: " + response.code(), Toast.LENGTH_SHORT).show();
+                    ErrorUtils.showErrorMessage(getContext(), response, "Delete failed");
                 }
             }
 
@@ -319,18 +341,25 @@ public class InventoryDetailFragment extends Fragment {
         });
     }
 
-    // Helpers
+    /**
-
+     * Notifies the parent fragment of a change and navigates back.
+     */
     private void notifyParentAndGoBack() {
         if (inventoryFragment != null)
             inventoryFragment.onInventoryChanged();
         navigateBack();
     }
 
+    /**
+     * Navigates back to the previous fragment.
+     */
     private void navigateBack() {
         NavHostFragment.findNavController(this).popBackStack();
     }
 
+    /**
+     * Enables or disables action buttons.
+     */
     private void setButtonsEnabled(boolean enabled) {
         btnSave.setEnabled(enabled);
         btnDelete.setEnabled(enabled);

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

@@ -3,9 +3,7 @@ package com.example.petstoremobile.fragments.listfragments.detailfragments;
 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.navigation.fragment.NavHostFragment;
 
@@ -13,7 +11,6 @@ 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.Spinner;
@@ -24,9 +21,8 @@ import com.example.petstoremobile.R;
 import com.example.petstoremobile.adapters.BlackTextArrayAdapter;
 import com.example.petstoremobile.api.PetApi;
 import com.example.petstoremobile.dtos.PetDTO;
-import com.example.petstoremobile.fragments.ListFragment;
-import com.example.petstoremobile.fragments.listfragments.PetFragment;
 import com.example.petstoremobile.utils.ActivityLogger;
+import com.example.petstoremobile.utils.ErrorUtils;
 import com.example.petstoremobile.utils.InputValidator;
 
 import javax.inject.Inject;
@@ -36,6 +32,9 @@ import retrofit2.Call;
 import retrofit2.Callback;
 import retrofit2.Response;
 
+/**
+ * Fragment for displaying and editing pet details.
+ */
 @AndroidEntryPoint
 public class PetDetailFragment extends Fragment {
 
@@ -66,7 +65,9 @@ public class PetDetailFragment extends Fragment {
         return view;
     }
 
-    //Method to Update or Add a pet
+    /**
+     * Handles the saving of pet data (adding/updating).
+     */
     private void savePet() {
         // Validates all fields using InputValidator
         if (!InputValidator.isNotEmpty(etPetName, "Pet Name")) return;
@@ -104,7 +105,7 @@ public class PetDetailFragment extends Fragment {
                         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();
+                        ErrorUtils.showErrorMessage(getContext(), response, "Failed to update pet");
                     }
                 }
 
@@ -112,7 +113,7 @@ public class PetDetailFragment extends Fragment {
                 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();
+                    Toast.makeText(getContext(), "Network error: " + t.getMessage(), Toast.LENGTH_SHORT).show();
                 }
             });
         } else {
@@ -125,7 +126,7 @@ public class PetDetailFragment extends Fragment {
                         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();
+                        ErrorUtils.showErrorMessage(getContext(), response, "Failed to add pet");
                     }
                 }
 
@@ -133,13 +134,15 @@ public class PetDetailFragment extends Fragment {
                 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();
+                    Toast.makeText(getContext(), "Network error: " + t.getMessage(), 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())
@@ -155,7 +158,7 @@ public class PetDetailFragment extends Fragment {
                                 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();
+                                ErrorUtils.showErrorMessage(getContext(), response, "Failed to delete pet");
                             }
                         }
 
@@ -163,7 +166,7 @@ public class PetDetailFragment extends Fragment {
                         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();
+                            Toast.makeText(getContext(), "Network error: " + t.getMessage(), Toast.LENGTH_SHORT).show();
                         }
                     });
                 })
@@ -171,12 +174,16 @@ public class PetDetailFragment extends Fragment {
                 .show();
     }
 
-    //Helper method to navigate back to the list
+    /**
+     * Navigates back to the previous screen.
+     */
     private void navigateBack() {
         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")) {
@@ -208,7 +215,9 @@ public class PetDetailFragment extends Fragment {
         }
     }
 
-    //helper function to get controls from layout
+    /**
+     * Binds UI components from the layout.
+     */
     private void initViews(View view) {
         tvMode = view.findViewById(R.id.tvMode);
         tvPetId = view.findViewById(R.id.tvPetId);
@@ -223,7 +232,9 @@ public class PetDetailFragment extends Fragment {
         btnBack = view.findViewById(R.id.btnBack);
     }
 
-    //helper function to set up the spinner menu for pet status
+    /**
+     * Initializes the spinner for pet status selection.
+     */
     private void setupSpinner() {
         BlackTextArrayAdapter<String> adapter = new BlackTextArrayAdapter<>(requireContext(),
                 android.R.layout.simple_spinner_item,

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

@@ -1,38 +1,25 @@
 package com.example.petstoremobile.fragments.listfragments.detailfragments;
 
-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 android.provider.MediaStore;
-import android.util.Log;
 import android.view.*;
 import android.widget.*;
-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 androidx.navigation.fragment.NavHostFragment;
 
 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.adapters.BlackTextArrayAdapter;
 import com.example.petstoremobile.api.*;
 import com.example.petstoremobile.api.auth.TokenManager;
 import com.example.petstoremobile.dtos.*;
 import com.example.petstoremobile.viewmodels.ProductViewModel;
-import com.example.petstoremobile.utils.Resource;
+import com.example.petstoremobile.utils.ErrorUtils;
 import com.example.petstoremobile.utils.FileUtils;
+import com.example.petstoremobile.utils.GlideUtils;
+import com.example.petstoremobile.utils.ImagePickerHelper;
 
 import java.io.File;
 import java.math.BigDecimal;
@@ -46,6 +33,9 @@ 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 {
 
@@ -65,52 +55,43 @@ public class ProductDetailFragment extends Fragment {
     private List<CategoryDTO> categoryList = new ArrayList<>();
     private Uri photoUri;
     private ProductViewModel viewModel;
+    private ImagePickerHelper imagePickerHelper;
 
     @Inject @Named("baseUrl") String baseUrl;
     @Inject TokenManager tokenManager;
 
-    private ActivityResultLauncher<Intent> galleryLauncher;
+    /**
-    private ActivityResultLauncher<Uri> cameraLauncher;
+     * Initializes activity launchers and the ImagePickerHelper.
-    private ActivityResultLauncher<String> permissionLauncher;
+     */
-
     @Override
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         viewModel = new ViewModelProvider(this).get(ProductViewModel.class);
 
-        galleryLauncher = registerForActivityResult(
+        imagePickerHelper = new ImagePickerHelper(this, "product_photo.jpg", new ImagePickerHelper.ImagePickerListener() {
-                new ActivityResultContracts.StartActivityForResult(),
+            @Override
-                result -> {
+            public void onImagePicked(Uri uri) {
-                    if (result.getResultCode() == Activity.RESULT_OK && result.getData() != null) {
+                photoUri = uri;
-                        Uri selectedImage = result.getData().getData();
+                Glide.with(ProductDetailFragment.this).load(uri).into(ivProductImage);
-                        Glide.with(this).load(selectedImage).into(ivProductImage);
-                        photoUri = selectedImage;
                 hasImage = true;
                 isImageChanged = true;
                 isImageRemoved = false;
             }
-                }
-        );
-        cameraLauncher = registerForActivityResult(
-                new ActivityResultContracts.TakePicture(),
-                success -> {
-                    if (success) {
-                        Glide.with(this).load(photoUri).into(ivProductImage);
-                        hasImage = true;
-                        isImageChanged = true;
-                        isImageRemoved = false;
-                    }
-                }
-        );
-        permissionLauncher = registerForActivityResult(
-                new ActivityResultContracts.RequestPermission(),
-                granted -> {
-                    if (granted) launchCamera();
-                    else Toast.makeText(getContext(), "Camera permission denied", Toast.LENGTH_SHORT).show();
-                }
-        );
-    }
 
+            @Override
+            public void onImageRemoved() {
+                photoUri = null;
+                hasImage = false;
+                isImageChanged = false;
+                isImageRemoved = true;
+                ivProductImage.setImageResource(R.drawable.placeholder2);
+            }
+        });
+    }
+
+    /**
+     * Inflates the layout and initializes UI components and listeners.
+     */
     @Override
     public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
@@ -122,10 +103,13 @@ public class ProductDetailFragment extends Fragment {
         btnBack.setOnClickListener(v -> navigateBack());
         btnSave.setOnClickListener(v -> saveProduct());
         btnDelete.setOnClickListener(v -> confirmDelete());
-        ivProductImage.setOnClickListener(v -> showImagePickerDialog());
+        ivProductImage.setOnClickListener(v -> imagePickerHelper.showImagePickerDialog("Select Product Image", hasImage));
         return view;
     }
 
+    /**
+     * get the UI components from the layout.
+     */
     private void initViews(View v) {
         tvMode          = v.findViewById(R.id.tvProductMode);
         tvProductId     = v.findViewById(R.id.tvProductId);
@@ -139,63 +123,21 @@ public class ProductDetailFragment extends Fragment {
         ivProductImage  = v.findViewById(R.id.ivProductImage);
     }
 
-    // Helper function to show the image picker dialog
+    /**
-    private void showImagePickerDialog() {
+     * Fetches all product categories for the selection spinner.
-        List<String> options = new ArrayList<>();
+     */
-        options.add("Take Photo");
-        options.add("Choose from Gallery");
-        if (hasImage) {
-            options.add("Remove Photo");
-        }
-
-        new AlertDialog.Builder(requireContext())
-                .setTitle("Select Product Image")
-                .setItems(options.toArray(new String[0]), (dialog, which) -> {
-                    String selectedOption = options.get(which);
-                    if (selectedOption.equals("Take Photo")) {
-                        if (ContextCompat.checkSelfPermission(requireContext(), Manifest.permission.CAMERA)
-                                == PackageManager.PERMISSION_GRANTED) {
-                            launchCamera();
-                        } else {
-                            permissionLauncher.launch(Manifest.permission.CAMERA);
-                        }
-                    } else if (selectedOption.equals("Choose from Gallery")) {
-                        Intent intent = new Intent(Intent.ACTION_PICK, MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
-                        galleryLauncher.launch(intent);
-                    } else if (selectedOption.equals("Remove Photo")) {
-                        removePhoto();
-                    }
-                })
-                .show();
-    }
-
-    // Helper function to remove the photo locally
-    private void removePhoto() {
-        photoUri = null;
-        hasImage = false;
-        isImageChanged = false;
-        isImageRemoved = true;
-        Glide.with(this).load(R.drawable.placeholder2).into(ivProductImage);
-    }
-
-    // Helper function to launch the camera
-    private void launchCamera() {
-        File photoFile = new File(requireContext().getCacheDir(), "product_photo.jpg");
-        photoUri = FileProvider.getUriForFile(requireContext(), requireContext().getPackageName() + ".fileprovider", photoFile);
-        cameraLauncher.launch(photoUri);
-    }
-
-    // Helper function to load categories from the backend for the spinner
     private void loadCategories() {
         viewModel.getAllCategories(0, 100).observe(getViewLifecycleOwner(), resource -> {
-            if (resource != null && resource.status == Resource.Status.SUCCESS && resource.data != null) {
+            if (resource != null && resource.status == com.example.petstoremobile.utils.Resource.Status.SUCCESS && resource.data != null) {
                 categoryList = resource.data.getContent();
                 populateCategorySpinner();
             }
         });
     }
 
-    // Helper function to populate the category spinner
+    /**
+     * Fills the spinner with category names.
+     */
     private void populateCategorySpinner() {
         List<String> names = new ArrayList<>();
         names.add("-- Select Category --");
@@ -211,6 +153,9 @@ public class ProductDetailFragment extends Fragment {
         }
     }
 
+    /**
+     * Checks if the fragment was opened with existing product data for editing.
+     */
     private void handleArguments() {
         Bundle a = getArguments();
         if (a != null && a.containsKey("prodId")) {
@@ -235,34 +180,34 @@ public class ProductDetailFragment extends Fragment {
         }
     }
 
-    //load the product image from the backend
+    /**
+     * 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();
 
-        Object loadTarget = imageUrl;
+        GlideUtils.loadImageWithToken(requireContext(), ivProductImage, imageUrl, token, R.drawable.placeholder2, new GlideUtils.ImageLoadListener() {
-        if (token != null) {
+            @Override
-            loadTarget = new GlideUrl(imageUrl, new LazyHeaders.Builder()
+            public void onResourceReady() {
-                    .addHeader("Authorization", "Bearer " + token)
+                hasImage = true;
-                    .build());
             }
 
-        Glide.with(this)
+            @Override
-                .load(loadTarget)
+            public void onLoadFailed() {
-                .skipMemoryCache(true)
+                hasImage = false;
-                .diskCacheStrategy(DiskCacheStrategy.NONE)
+            }
-                .placeholder(R.drawable.placeholder2)
+        });
-                .error(R.drawable.placeholder2)
-                .into(ivProductImage);
     }
 
-    // Function to check any changes to the image and perform the appropriate action
+    /**
-    // updating/adding photo, removing photo or no change
+     * 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 != null && resource.status != com.example.petstoremobile.utils.Resource.Status.LOADING) {
-                    if (resource.status == Resource.Status.SUCCESS) {
+                    if (resource.status == com.example.petstoremobile.utils.Resource.Status.SUCCESS) {
                         Toast.makeText(getContext(), successMsg, Toast.LENGTH_SHORT).show();
                     } else {
                         Toast.makeText(getContext(), successMsg + " (but image removal failed)", Toast.LENGTH_SHORT).show();
@@ -278,8 +223,9 @@ public class ProductDetailFragment extends Fragment {
         }
     }
 
-    // Helper function to upload the product image by calling the backend
+    /**
-    // and then navigate back to the previous screen
+     * Uploads the selected image file to the server.
+     */
     private void uploadProductImageAndNavigate(Uri uri, String successMsg) {
         File file = FileUtils.getFileFromUri(requireContext(), uri);
         if (file == null) {
@@ -292,8 +238,8 @@ public class ProductDetailFragment extends Fragment {
         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 != null && resource.status != com.example.petstoremobile.utils.Resource.Status.LOADING) {
-                if (resource.status == Resource.Status.SUCCESS) {
+                if (resource.status == com.example.petstoremobile.utils.Resource.Status.SUCCESS) {
                     Toast.makeText(getContext(), successMsg, Toast.LENGTH_SHORT).show();
                 } else {
                     Toast.makeText(getContext(), successMsg + " (but image upload failed)", Toast.LENGTH_SHORT).show();
@@ -303,6 +249,9 @@ public class ProductDetailFragment extends Fragment {
         });
     }
 
+    /**
+     * Validates input fields and saves product information to the backend.
+     */
     private void saveProduct() {
         String name = etProductName.getText().toString().trim();
         String desc = etProductDesc.getText().toString().trim();
@@ -330,8 +279,8 @@ public class ProductDetailFragment extends Fragment {
 
         if (isEditing) {
             viewModel.updateProduct(prodId, dto).observe(getViewLifecycleOwner(), resource -> {
-                if (resource != null && resource.status != Resource.Status.LOADING) {
+                if (resource != null && resource.status != com.example.petstoremobile.utils.Resource.Status.LOADING) {
-                    if (resource.status == Resource.Status.SUCCESS) {
+                    if (resource.status == com.example.petstoremobile.utils.Resource.Status.SUCCESS) {
                         performPendingImageActions("Updated");
                     } else {
                         Toast.makeText(getContext(), "Error: " + resource.message, Toast.LENGTH_SHORT).show();
@@ -340,8 +289,8 @@ public class ProductDetailFragment extends Fragment {
             });
         } else {
             viewModel.createProduct(dto).observe(getViewLifecycleOwner(), resource -> {
-                if (resource != null && resource.status != Resource.Status.LOADING) {
+                if (resource != null && resource.status != com.example.petstoremobile.utils.Resource.Status.LOADING) {
-                    if (resource.status == Resource.Status.SUCCESS && resource.data != null) {
+                    if (resource.status == com.example.petstoremobile.utils.Resource.Status.SUCCESS && resource.data != null) {
                         prodId = resource.data.getProdId();
                         performPendingImageActions("Saved");
                     } else {
@@ -352,21 +301,26 @@ public class ProductDetailFragment extends Fragment {
         }
     }
 
-    // Function to delete the product from the server
+    /**
+     * Displays a confirmation dialog before deleting the product.
+     */
     private void confirmDelete() {
-        new AlertDialog.Builder(requireContext())
+        new androidx.appcompat.app.AlertDialog.Builder(requireContext())
                 .setTitle("Delete Product?")
                 .setPositiveButton("Yes", (d, w) ->
                         viewModel.deleteProduct(prodId).observe(getViewLifecycleOwner(), resource -> {
-                            if (resource != null && resource.status == Resource.Status.SUCCESS) {
+                            if (resource != null && resource.status == com.example.petstoremobile.utils.Resource.Status.SUCCESS) {
                                 navigateBack();
-                            } else if (resource != null && resource.status == Resource.Status.ERROR) {
+                            } else if (resource != null && resource.status == com.example.petstoremobile.utils.Resource.Status.ERROR) {
                                 Toast.makeText(getContext(), "Delete failed: " + resource.message, Toast.LENGTH_SHORT).show();
                             }
                         }))
                 .setNegativeButton("No", null).show();
     }
 
+    /**
+     * Navigates back to the previous fragment.
+     */
     private void navigateBack() {
         NavHostFragment.findNavController(this).popBackStack();
     }

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

@@ -13,7 +13,8 @@ import com.example.petstoremobile.R;
 import com.example.petstoremobile.adapters.BlackTextArrayAdapter;
 import com.example.petstoremobile.api.*;
 import com.example.petstoremobile.dtos.*;
-import com.example.petstoremobile.fragments.ListFragment;
+import com.example.petstoremobile.utils.ErrorUtils;
+
 import java.math.BigDecimal;
 import java.util.*;
 
@@ -22,6 +23,9 @@ import javax.inject.Inject;
 import dagger.hilt.android.AndroidEntryPoint;
 import retrofit2.*;
 
+/**
+ * Fragment for displaying and editing the relationship between products and suppliers,
+ */
 @AndroidEntryPoint
 public class ProductSupplierDetailFragment extends Fragment {
 
@@ -57,6 +61,9 @@ public class ProductSupplierDetailFragment extends Fragment {
         return view;
     }
 
+    /**
+     * Initializes UI components from the layout.
+     */
     private void initViews(View v) {
         tvMode          = v.findViewById(R.id.tvPSMode);
         spinnerProduct  = v.findViewById(R.id.spinnerPSProduct);
@@ -67,11 +74,17 @@ public class ProductSupplierDetailFragment extends Fragment {
         btnBack         = v.findViewById(R.id.btnPSBack);
     }
 
+    /**
+     * Fetches products and suppliers to populate the spinners.
+     */
     private void loadData() {
         loadProducts();
         loadSuppliers();
     }
 
+    /**
+     * Loads the list of products from the API.
+     */
     private void loadProducts() {
         productApi.getAllProducts(null, 0, 200)
                 .enqueue(new Callback<PageResponse<ProductDTO>>() {
@@ -88,6 +101,9 @@ public class ProductSupplierDetailFragment extends Fragment {
                 });
     }
 
+    /**
+     * Populates the product spinner.
+     */
     private void populateProductSpinner() {
         List<String> names = new ArrayList<>();
         names.add("-- Select Product --");
@@ -103,6 +119,9 @@ public class ProductSupplierDetailFragment extends Fragment {
         }
     }
 
+    /**
+     * Loads the list of suppliers from the API.
+     */
     private void loadSuppliers() {
         supplierApi.getAllSuppliers(0, 200)
                 .enqueue(new Callback<PageResponse<SupplierDTO>>() {
@@ -119,6 +138,9 @@ public class ProductSupplierDetailFragment extends Fragment {
                 });
     }
 
+    /**
+     * Populates the supplier spinner.
+     */
     private void populateSupplierSpinner() {
         List<String> names = new ArrayList<>();
         names.add("-- Select Supplier --");
@@ -134,6 +156,9 @@ public class ProductSupplierDetailFragment extends Fragment {
         }
     }
 
+    /**
+     * 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")) {
@@ -151,6 +176,9 @@ public class ProductSupplierDetailFragment extends Fragment {
         }
     }
 
+    /**
+     * Validates input and saves the product-supplier to the backend.
+     */
     private void save() {
         if (spinnerProduct.getSelectedItemPosition() == 0) {
             Toast.makeText(getContext(), "Select a product", Toast.LENGTH_SHORT).show(); return;
@@ -183,6 +211,9 @@ public class ProductSupplierDetailFragment extends Fragment {
         }
     }
 
+    /**
+     * callback for product-supplier save/update operations.
+     */
     private Callback<ProductSupplierDTO> simpleCallback(String msg) {
         return new Callback<>() {
             public void onResponse(Call<ProductSupplierDTO> c, Response<ProductSupplierDTO> r) {
@@ -190,13 +221,7 @@ public class ProductSupplierDetailFragment extends Fragment {
                     Toast.makeText(getContext(), msg, Toast.LENGTH_SHORT).show();
                     navigateBack();
                 } else {
-                    try {
+                    ErrorUtils.showErrorMessage(getContext(), r, "Error " + r.code());
-                        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) {
@@ -206,6 +231,9 @@ public class ProductSupplierDetailFragment extends Fragment {
         };
     }
 
+    /**
+     * Shows a confirmation dialog before deleting a product-supplier relationship.
+     */
     private void confirmDelete() {
         new AlertDialog.Builder(requireContext())
                 .setTitle("Delete?")
@@ -223,6 +251,9 @@ public class ProductSupplierDetailFragment extends Fragment {
                 .setNegativeButton("No", null).show();
     }
 
+    /**
+     * Navigates back to the previous screen.
+     */
     private void navigateBack() {
         NavHostFragment.findNavController(this).popBackStack();
     }

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

@@ -9,16 +9,21 @@ import androidx.fragment.app.Fragment;
 import androidx.navigation.fragment.NavHostFragment;
 
 import com.example.petstoremobile.R;
-import com.example.petstoremobile.fragments.ListFragment;
 
 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;
 
+    /**
+     * Inflates the layout, initializes views, and populates order data from arguments.
+     */
     @Override
     public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {

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

@@ -20,6 +20,7 @@ import com.example.petstoremobile.api.ServiceApi;
 import com.example.petstoremobile.dtos.ServiceDTO;
 import com.example.petstoremobile.fragments.listfragments.ServiceFragment;
 import com.example.petstoremobile.utils.ActivityLogger;
+import com.example.petstoremobile.utils.ErrorUtils;
 import com.example.petstoremobile.utils.InputValidator;
 
 import javax.inject.Inject;
@@ -29,6 +30,9 @@ import retrofit2.Call;
 import retrofit2.Callback;
 import retrofit2.Response;
 
+/**
+ * Fragment for displaying and editing service details.
+ */
 @AndroidEntryPoint
 public class ServiceDetailFragment extends Fragment {
 
@@ -41,7 +45,9 @@ public class ServiceDetailFragment extends Fragment {
 
     @Inject ServiceApi serviceApi;
 
-    //set the service fragment to the parent so we refer back to service view when save or delete is done
+    /**
+     * Sets the parent service fragment to notify of changes.
+     */
     public void setServiceFragment(ServiceFragment fragment) {
         this.serviceFragment = fragment;
     }
@@ -63,7 +69,9 @@ public class ServiceDetailFragment extends Fragment {
         return view;
     }
 
-    //Method to Update or Add a service
+    /**
+     * Handles the saving of service data (adding or updating).
+     */
     private void saveService() {
         // Validates all fields using InputValidator
         if (!InputValidator.isNotEmpty(etServiceName, "Service Name")) return;
@@ -96,7 +104,7 @@ public class ServiceDetailFragment extends Fragment {
                         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();
+                        ErrorUtils.showErrorMessage(getContext(), response, "Failed to update service");
                     }
                 }
 
@@ -104,7 +112,7 @@ public class ServiceDetailFragment extends Fragment {
                 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();
+                    Toast.makeText(getContext(), "Network error: " + t.getMessage(), Toast.LENGTH_SHORT).show();
                 }
             });
         } else {
@@ -117,7 +125,7 @@ public class ServiceDetailFragment extends Fragment {
                         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();
+                        ErrorUtils.showErrorMessage(getContext(), response, "Failed to add service");
                     }
                 }
 
@@ -125,13 +133,15 @@ public class ServiceDetailFragment extends Fragment {
                 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();
+                    Toast.makeText(getContext(), "Network error: " + t.getMessage(), 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())
@@ -146,7 +156,7 @@ public class ServiceDetailFragment extends Fragment {
                                 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();
+                                ErrorUtils.showErrorMessage(getContext(), response, "Failed to delete service");
                             }
                         }
 
@@ -154,7 +164,7 @@ public class ServiceDetailFragment extends Fragment {
                         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();
+                            Toast.makeText(getContext(), "Network error: " + t.getMessage(), Toast.LENGTH_SHORT).show();
                         }
                     });
                 })
@@ -162,12 +172,16 @@ public class ServiceDetailFragment extends Fragment {
                 .show();
     }
 
-    //Helper method to navigate back to the list
+    /**
+     * Navigates back to the previous screen.
+     */
     private void navigateBack() {
         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")) {
@@ -192,7 +206,9 @@ public class ServiceDetailFragment extends Fragment {
         }
     }
 
-    //helper function to get controls from layout
+    /**
+     * Set UI components from the layout.
+     */
     private void initViews(View view) {
         tvMode = view.findViewById(R.id.tvMode);
         tvServiceId = view.findViewById(R.id.tvServiceId);

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

@@ -19,7 +19,9 @@ import com.example.petstoremobile.R;
 import com.example.petstoremobile.api.SupplierApi;
 import com.example.petstoremobile.dtos.SupplierDTO;
 import com.example.petstoremobile.utils.ActivityLogger;
+import com.example.petstoremobile.utils.ErrorUtils;
 import com.example.petstoremobile.utils.InputValidator;
+import com.example.petstoremobile.utils.UIUtils;
 
 import javax.inject.Inject;
 
@@ -28,6 +30,9 @@ import retrofit2.Call;
 import retrofit2.Callback;
 import retrofit2.Response;
 
+/**
+ * Fragment for displaying and editing supplier details.
+ */
 @AndroidEntryPoint
 public class SupplierDetailFragment extends Fragment {
 
@@ -56,7 +61,9 @@ public class SupplierDetailFragment extends Fragment {
         return view;
     }
 
-    //Method to Update or Add a supplier
+    /**
+     * Handles the saving of supplier data (adding or updating).
+     */
     private void saveSupplier() {
         // Validates all fields using InputValidator
         if (!InputValidator.isNotEmpty(etSupCompany, "Company Name")) return;
@@ -92,7 +99,7 @@ public class SupplierDetailFragment extends Fragment {
                         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();
+                        ErrorUtils.showErrorMessage(getContext(), response, "Failed to update supplier");
                     }
                 }
 
@@ -100,7 +107,7 @@ public class SupplierDetailFragment extends Fragment {
                 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();
+                    Toast.makeText(getContext(), "Network error: " + t.getMessage(), Toast.LENGTH_SHORT).show();
                 }
             });
         } else {
@@ -113,7 +120,7 @@ public class SupplierDetailFragment extends Fragment {
                         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();
+                        ErrorUtils.showErrorMessage(getContext(), response, "Failed to add supplier");
                     }
                 }
 
@@ -121,13 +128,15 @@ public class SupplierDetailFragment extends Fragment {
                 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();
+                    Toast.makeText(getContext(), "Network error: " + t.getMessage(), 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())
@@ -142,7 +151,7 @@ public class SupplierDetailFragment extends Fragment {
                                 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();
+                                ErrorUtils.showErrorMessage(getContext(), response, "Failed to delete supplier");
                             }
                         }
 
@@ -150,7 +159,7 @@ public class SupplierDetailFragment extends Fragment {
                         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();
+                            Toast.makeText(getContext(), "Network error: " + t.getMessage(), Toast.LENGTH_SHORT).show();
                         }
                     });
                 })
@@ -158,12 +167,16 @@ public class SupplierDetailFragment extends Fragment {
                 .show();
     }
 
-    //Helper method to navigate back to the list
+    /**
+     * Navigates back to the previous screen.
+     */
     private void navigateBack() {
         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")) {
@@ -189,7 +202,9 @@ public class SupplierDetailFragment extends Fragment {
         }
     }
 
-    //helper function to get controls from layout
+    /**
+     * Initializes the UI components and sets up formatting for phone input.
+     */
     private void initViews(View view) {
         tvMode = view.findViewById(R.id.tvMode);
         tvSupId = view.findViewById(R.id.tvSupId);
@@ -200,8 +215,7 @@ public class SupplierDetailFragment extends Fragment {
         etSupPhone = view.findViewById(R.id.etSupPhone);
 
         // Add phone number formatting (CA) and limit length to 14 characters
-        etSupPhone.addTextChangedListener(new android.telephony.PhoneNumberFormattingTextWatcher("CA"));
+        UIUtils.formatPhoneInput(etSupPhone);
-        etSupPhone.setFilters(new android.text.InputFilter[]{new android.text.InputFilter.LengthFilter(14)});
 
         btnSaveSupplier = view.findViewById(R.id.btnSaveSupplier);
         btnDeleteSupplier = view.findViewById(R.id.btnDeleteSupplier);

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

@@ -1,22 +1,11 @@
 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.fragment.app.Fragment;
 import androidx.navigation.fragment.NavHostFragment;
 
-import android.provider.MediaStore;
 import android.util.Log;
 import android.view.LayoutInflater;
 import android.view.View;
@@ -26,21 +15,14 @@ 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.api.PetApi;
 import com.example.petstoremobile.api.auth.TokenManager;
-import com.example.petstoremobile.fragments.ListFragment;
+import com.example.petstoremobile.utils.FileUtils;
-import com.example.petstoremobile.fragments.listfragments.detailfragments.PetDetailFragment;
+import com.example.petstoremobile.utils.GlideUtils;
+import com.example.petstoremobile.utils.ImagePickerHelper;
 
 import java.io.File;
-import java.io.FileOutputStream;
-import java.io.InputStream;
-import java.util.ArrayList;
-import java.util.List;
 import java.util.Locale;
 
 import javax.inject.Inject;
@@ -60,7 +42,6 @@ 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 boolean hasImage = false;
 
@@ -68,59 +49,32 @@ public class PetProfileFragment extends Fragment {
     @Inject @Named("baseUrl") String baseUrl;
     @Inject TokenManager tokenManager;
 
-    // launchers for camera and gallery
+    private ImagePickerHelper imagePickerHelper;
-    private ActivityResultLauncher<Intent> galleryLauncher;
-    private ActivityResultLauncher<Uri> cameraLauncher;
-    private ActivityResultLauncher<String> permissionLauncher;
 
 
+    /**
+     * Initializes activity launchers for gallery, camera, and permissions.
+     */
     @Override
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
 
-        // Launcher to open gallery to select image
+        imagePickerHelper = new ImagePickerHelper(this, "pet_photo.jpg", new ImagePickerHelper.ImagePickerListener() {
-        galleryLauncher = registerForActivityResult(
+            @Override
-                new ActivityResultContracts.StartActivityForResult(),
+            public void onImagePicked(Uri uri) {
-                result -> {
+                uploadPetImage(uri);
-                    if (result.getResultCode() == Activity.RESULT_OK && result.getData() != null) {
-                        Uri selectedImage = result.getData().getData();
-                        uploadPetImage(selectedImage);
-                    }
-                }
-        );
-
-        // 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, initializes views, and sets up click listeners.
+     */
     @Override
     public View onCreateView(LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
@@ -164,78 +118,38 @@ public class PetProfileFragment extends Fragment {
 
         //Make change photo button ask user to select a new photo
         btnChangePhoto.setOnClickListener(v -> {
-            List<String> options = new ArrayList<>();
+            imagePickerHelper.showImagePickerDialog("Change Pet Photo", hasImage);
-            options.add("Take Photo");
-            options.add("Choose from Gallery");
-            if (hasImage) {
-                options.add("Remove Photo");
-            }
-
-            new AlertDialog.Builder(requireContext())
-                    .setTitle("Change Pet Photo")
-                    .setItems(options.toArray(new String[0]), (dialog, which) -> {
-                        String selected = options.get(which);
-                        if (selected.equals("Take Photo")) {
-                            // 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 if (selected.equals("Choose from Gallery")) {
-                            Intent intent = new Intent(Intent.ACTION_PICK, MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
-                            galleryLauncher.launch(intent);
-                        } else if (selected.equals("Remove Photo")) {
-                            deletePetImage();
-                        }
-                    })
-                    .show();
         });
 
         return view;
     }
 
-    // Helper function to load pet image from backend
+    /**
+     * Fetches and displays the pet's image from the server.
+     */
     private void loadPetImage(int petId) {
         String imageUrl = baseUrl + String.format(Locale.US, PetApi.PET_IMAGE_PATH, petId);
         String token = tokenManager.getToken();
 
-        Object loadTarget = imageUrl;
+        GlideUtils.loadImageWithToken(requireContext(), imgPet, imageUrl, token, R.drawable.placeholder, new GlideUtils.ImageLoadListener() {
-        if (token != null) {
-            loadTarget = new GlideUrl(imageUrl, new LazyHeaders.Builder()
-                    .addHeader("Authorization", "Bearer " + token)
-                    .build());
-        }
-
-        Glide.with(this)
-                .load(loadTarget)
-                .skipMemoryCache(true)
-                .diskCacheStrategy(DiskCacheStrategy.NONE)
-                .placeholder(R.drawable.placeholder)
-                .error(R.drawable.placeholder)
-                .listener(new com.bumptech.glide.request.RequestListener<android.graphics.drawable.Drawable>() {
             @Override
-                    public boolean onLoadFailed(@androidx.annotation.Nullable com.bumptech.glide.load.engine.GlideException e, Object model, com.bumptech.glide.request.target.Target<android.graphics.drawable.Drawable> target, boolean isFirstResource) {
+            public void onResourceReady() {
-                        hasImage = false;
-                        return false;
-                    }
-
-                    @Override
-                    public boolean onResourceReady(android.graphics.drawable.Drawable resource, Object model, com.bumptech.glide.request.target.Target<android.graphics.drawable.Drawable> target, com.bumptech.glide.load.DataSource dataSource, boolean isFirstResource) {
                 hasImage = true;
-                        return false;
-                    }
-                })
-                .into(imgPet);
             }
 
-    // Helper function to upload pet image to backend
+            @Override
+            public void onLoadFailed() {
+                hasImage = false;
+            }
+        });
+    }
+
+    /**
+     * Uploads a selected or captured image a pet photo through the API.
+     */
     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
@@ -266,6 +180,9 @@ public class PetProfileFragment extends Fragment {
         }
     }
 
+    /**
+     * Sends a request to the API to remove the current pet photo.
+     */
     private void deletePetImage() {
         petApi.deletePetImage((long) petId).enqueue(new Callback<Void>() {
             @Override
@@ -286,30 +203,4 @@ public class PetProfileFragment extends Fragment {
             }
         });
     }
-
-    // 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);
-            }
-            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/utils/ErrorUtils.java

@@ -0,0 +1,32 @@
+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 retrofit2.Response;
+
+/**
+ * Utility class for handling API error responses.
+ */
+public class ErrorUtils {
+    /**
+     * Shows an error message to toast based on the response.
+     */
+    public static void showErrorMessage(Context context, Response<?> response, String defaultMessage) {
+        try {
+            if (response.errorBody() != null) {
+                String errorJson = response.errorBody().string();
+                ErrorResponse errorResponse = new Gson().fromJson(errorJson, ErrorResponse.class);
+                if (errorResponse != null && errorResponse.getMessage() != null) {
+                    Toast.makeText(context, errorResponse.getMessage(), Toast.LENGTH_LONG).show();
+                    return;
+                }
+            }
+        } catch (Exception e) {
+            Log.e("ErrorUtils", "Error parsing error body", e);
+        }
+        Toast.makeText(context, defaultMessage, Toast.LENGTH_SHORT).show();
+    }
+}

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/UIUtils.java

@@ -0,0 +1,18 @@
+package com.example.petstoremobile.utils;
+
+import android.telephony.PhoneNumberFormattingTextWatcher;
+import android.text.InputFilter;
+import android.widget.EditText;
+
+/**
+ * Utility class for shared UI component logic and formatting.
+ */
+public class UIUtils {
+    /**
+     * Formats an EditText for to phone format
+     */
+    public static void formatPhoneInput(EditText editText) {
+        editText.addTextChangedListener(new PhoneNumberFormattingTextWatcher("CA"));
+        editText.setFilters(new InputFilter[]{new InputFilter.LengthFilter(14)});
+    }
+}