Refactor: Moved ConfirmationAlertDialogFragment to a separate file from AddNoteDialog

ConfirmationAlertDialogFragment is now a generic helper class for displaying a 2-button (positive & negative) confirmation dialog fragment on top of an existing dialog fragment

app/src/main/java/org/kiwix/kiwixmobile/di/components/ApplicationComponent.java

@@ -29,6 +29,7 @@ import org.kiwix.kiwixmobile.di.modules.NetworkModule;
 import org.kiwix.kiwixmobile.downloader.DownloadService;
 import org.kiwix.kiwixmobile.library.LibraryAdapter;
 import org.kiwix.kiwixmobile.main.AddNoteDialog;
+import org.kiwix.kiwixmobile.main.ConfirmationAlertDialogFragment;
 import org.kiwix.kiwixmobile.main.KiwixWebView;
 import org.kiwix.kiwixmobile.search.AutoCompleteAdapter;
 import org.kiwix.kiwixmobile.settings.KiwixSettingsActivity;
@@ -64,4 +65,6 @@ public interface ApplicationComponent {
   void inject(AutoCompleteAdapter autoCompleteAdapter);
 
   void inject(AddNoteDialog addNoteDialog);
+
+  void inject(ConfirmationAlertDialogFragment confirmationAlertDialogFragment);
 }

app/src/main/java/org/kiwix/kiwixmobile/main/AddNoteDialog.java

@@ -3,7 +3,6 @@ package org.kiwix.kiwixmobile.main;
 import android.Manifest;
 import android.app.Dialog;
 import android.content.Context;
-import android.content.DialogInterface;
 import android.content.Intent;
 import android.content.pm.PackageManager;
 import android.net.Uri;
@@ -24,7 +23,6 @@ import android.widget.Toast;
 
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
-import androidx.appcompat.app.AlertDialog;
 import androidx.appcompat.widget.Toolbar;
 import androidx.core.content.ContextCompat;
 import androidx.core.content.FileProvider;
@@ -58,7 +56,9 @@ import static org.kiwix.kiwixmobile.utils.Constants.NOTES_DIRECTORY;
  * Notes are saved as text files at location: "{External Storage}/Kiwix/Notes/ZimFileTitle/ArticleTitle.txt"
  * */
 
-public class AddNoteDialog extends DialogFragment {
+public class AddNoteDialog extends DialogFragment implements ConfirmationAlertDialogFragment.UserClickListener {
+
+  public static String TAG = "AddNoteDialog";
 
   @Inject
   SharedPreferenceUtil sharedPreferenceUtil;
@@ -77,8 +77,6 @@ public class AddNoteDialog extends DialogFragment {
   private boolean noteFileExists = false;
   private boolean noteEdited = false; // Keeps track of state of the note (whether edited since last save)
 
-  private final String TAG = "AddNoteDialog";
-
   public AddNoteDialog() {
     super();
     KiwixApplication.getApplicationComponent().inject(this);
@@ -169,13 +167,12 @@ public class AddNoteDialog extends DialogFragment {
   private void exitAddNoteDialog() {
     if(noteEdited) {
       // Custom AlertDialog for taking user confirmation before closing note dialog in case of unsaved changes
-      DialogFragment newFragment = new ConfirmationAlertDialogFragment(getDialog());
-      newFragment.show(getActivity().getSupportFragmentManager(), "ConfirmationAlertDialog");
+      DialogFragment newFragment = new ConfirmationAlertDialogFragment(TAG, R.string.confirmation_alert_dialog_message);
+      newFragment.show(getActivity().getSupportFragmentManager(), ConfirmationAlertDialogFragment.TAG);
 
     } else {
       // Closing unedited note dialog straightaway
-      Dialog dialog = getDialog();
-      dialog.dismiss();
+      dismissAddNoteDialog();
     }
   }
 
@@ -378,6 +375,22 @@ public class AddNoteDialog extends DialogFragment {
     Toast.makeText(getActivity(), stringResource, duration).show();
   }
 
+  // Methods from ConfirmationAlertDialogFragment.UserClickListener interface
+  @Override
+  public void onPositiveClick() {
+    dismissAddNoteDialog();
+  }
+
+  @Override
+  public void onNegativeClick() {
+    // Do nothing
+  }
+
+  private void dismissAddNoteDialog() {
+    Dialog dialog = getDialog();
+    dialog.dismiss();
+  }
+
   @Override
   public void onStart() {
     super.onStart();
@@ -399,45 +412,3 @@ public class AddNoteDialog extends DialogFragment {
   }
 
 }
-
-class ConfirmationAlertDialogFragment extends DialogFragment {
-  /**
-   * Helper class to show the alert dialog in case the user tries to exit the
-   * AddNoteDialog with unsaved file changes
-   **/
-
-  private SharedPreferenceUtil sharedPreferenceUtil = new SharedPreferenceUtil(KiwixApplication.getInstance());
-  private Dialog addNoteDialog;
-
-  public ConfirmationAlertDialogFragment(Dialog dialog) {
-    super();
-    addNoteDialog = dialog;
-  }
-
-  @Override
-  public Dialog onCreateDialog(Bundle savedInstanceState) {
-
-    AlertDialog.Builder builder;
-
-    if (sharedPreferenceUtil != null && sharedPreferenceUtil.nightMode()) {
-      // Night Mode support
-      builder = new AlertDialog.Builder(getActivity(), R.style.AppTheme_Dialog_Night);
-
-    } else {
-      builder = new AlertDialog.Builder(getActivity());
-
-    }
-    builder.setMessage(getString(R.string.confirmation_alert_dialog_message))
-        .setPositiveButton(getString(R.string.yes), new DialogInterface.OnClickListener() {
-          @Override
-          public void onClick(DialogInterface dialog, int which) {
-            // User sure of discarding unsaved changes and closing note dialog
-            addNoteDialog.dismiss();
-          }
-        })
-        .setNegativeButton(getString(R.string.cancel), null); // Do nothing for 'Cancel' button
-
-    return builder.create();
-  }
-
-}

app/src/main/java/org/kiwix/kiwixmobile/main/ConfirmationAlertDialogFragment.java

@@ -0,0 +1,85 @@
+package org.kiwix.kiwixmobile.main;
+
+import android.app.Dialog;
+import android.content.DialogInterface;
+import android.os.Bundle;
+
+import androidx.appcompat.app.AlertDialog;
+import androidx.fragment.app.DialogFragment;
+import androidx.fragment.app.Fragment;
+
+import org.kiwix.kiwixmobile.KiwixApplication;
+import org.kiwix.kiwixmobile.R;
+import org.kiwix.kiwixmobile.utils.SharedPreferenceUtil;
+
+import javax.inject.Inject;
+
+/**
+ * Created by @Aditya-Sood as a part of GSoC 2019
+ *
+ * This is a generic helper class for displaying a 2-button (positive & negative) confirmation dialog fragment on top of an existing dialog fragment
+ *  - Only for confirmation dialogs with a Positive & Negative button
+ *  - If you also need a Neutral button, add it selectively (if-else) for the required use case (Take care of the callback interface as well)
+ *
+ * Currently used as:
+ *  - Helper class to show the alert dialog in case the user tries to exit the {@link AddNoteDialog} with unsaved file changes
+ *
+ **/
+
+public class ConfirmationAlertDialogFragment extends DialogFragment {
+
+  public static String TAG = "ConfirmationAlertDialog";
+  @Inject SharedPreferenceUtil sharedPreferenceUtil;
+  private int stringResource;
+  private String parentDialogFragmentTAG;
+
+  public ConfirmationAlertDialogFragment(String dialogFragmentTAG, int resourceId) {
+    super();
+    parentDialogFragmentTAG = dialogFragmentTAG;
+    stringResource = resourceId;
+    KiwixApplication.getApplicationComponent().inject(this);
+  }
+
+  @Override
+  public Dialog onCreateDialog(Bundle savedInstanceState) {
+    Fragment parentDialogFragment = getFragmentManager().findFragmentByTag(parentDialogFragmentTAG);
+
+    AlertDialog.Builder builder;
+
+    if (sharedPreferenceUtil != null && sharedPreferenceUtil.nightMode()) { // Night Mode support
+      builder = new AlertDialog.Builder(getActivity(), R.style.AppTheme_Dialog_Night);
+    } else {
+      builder = new AlertDialog.Builder(getActivity());
+    }
+
+    builder.setMessage(stringResource)
+        .setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
+          @Override
+          public void onClick(DialogInterface dialog, int which) {
+
+            if(parentDialogFragment != null) {
+              ((UserClickListener) parentDialogFragment).onPositiveClick();
+            }
+          }
+        })
+        .setNegativeButton(android.R.string.cancel, new DialogInterface.OnClickListener() {
+          @Override
+          public void onClick(DialogInterface dialog, int which) {
+
+            if(parentDialogFragment != null) {
+              ((UserClickListener) parentDialogFragment).onNegativeClick();
+            }
+          }
+        });
+
+    return builder.create();
+  }
+
+  /** Callback interface for responding to user clicks to a {@link ConfirmationAlertDialogFragment} dialog */
+  public interface UserClickListener {
+    void onPositiveClick();
+
+    void onNegativeClick();
+  }
+
+}

app/src/main/java/org/kiwix/kiwixmobile/main/MainActivity.java

@@ -989,7 +989,7 @@ public class MainActivity extends BaseActivity implements WebViewCallback,
   /** Creates the full screen AddNoteDialog, which is a DialogFragment */
   private void showAddNoteDialog() {
     FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction();
-    Fragment prev = getSupportFragmentManager().findFragmentByTag("AddNoteDialog");
+    Fragment prev = getSupportFragmentManager().findFragmentByTag(AddNoteDialog.TAG);
 
     // To prevent multiple instances of the DialogFragment
     if(prev != null) {
@@ -997,7 +997,7 @@ public class MainActivity extends BaseActivity implements WebViewCallback,
     } else {
       fragmentTransaction.addToBackStack(null);
       AddNoteDialog dialogFragment = new AddNoteDialog();
-      dialogFragment.show(fragmentTransaction, "AddNoteDialog");
+      dialogFragment.show(fragmentTransaction, AddNoteDialog.TAG);
     }
   }