Use a new WasUnpaired state that shows a dialog over a blank fragment

briar-android/src/main/java/org/briarproject/briar/android/mailbox/MailboxActivity.java

@@ -11,6 +11,7 @@ import org.briarproject.briar.R;
 import org.briarproject.briar.android.activity.ActivityComponent;
 import org.briarproject.briar.android.activity.BriarActivity;
 import org.briarproject.briar.android.fragment.FinalFragment;
+import org.briarproject.briar.android.view.BlankFragment;
 
 import javax.inject.Inject;
 
@@ -54,8 +55,7 @@ public class MailboxActivity extends BriarActivity {
 
 		viewModel.getPairingState().observeEvent(this, state -> {
 			if (state instanceof MailboxState.NotSetup) {
-				MailboxState.NotSetup s = (MailboxState.NotSetup) state;
+				onNotSetup();
-				onNotSetup(s.tellUserToWipeMailbox);
 			} else if (state instanceof MailboxState.ShowDownload) {
 				onShowDownload();
 			} else if (state instanceof MailboxState.ScanningQrCode) {
@@ -70,6 +70,9 @@ public class MailboxActivity extends BriarActivity {
 				onCameraError();
 			} else if (state instanceof MailboxState.IsPaired) {
 				onIsPaired(((MailboxState.IsPaired) state).isOnline);
+			} else if (state instanceof MailboxState.WasUnpaired) {
+				MailboxState.WasUnpaired s = (MailboxState.WasUnpaired) state;
+				onUnPaired(s.tellUserToWipeMailbox);
 			} else {
 				throw new AssertionError("Unknown state: " + state);
 			}
@@ -97,17 +100,8 @@ public class MailboxActivity extends BriarActivity {
 		}
 	}
 
-	private void onNotSetup(boolean tellUserToWipeMailbox) {
+	private void onNotSetup() {
 		progressBar.setVisibility(INVISIBLE);
-		if (tellUserToWipeMailbox) {
-			AlertDialog.Builder builder =
-					new AlertDialog.Builder(this, R.style.BriarDialogTheme);
-			builder.setTitle(R.string.mailbox_status_unlink_no_wipe_title);
-			builder.setMessage(R.string.mailbox_status_unlink_no_wipe_message);
-			builder.setNeutralButton(R.string.got_it,
-					(dialog, which) -> dialog.cancel());
-			builder.show();
-		}
 		getSupportFragmentManager().beginTransaction()
 				.replace(R.id.fragmentContainer, new SetupIntroFragment(),
 						SetupIntroFragment.TAG)
@@ -137,7 +131,7 @@ public class MailboxActivity extends BriarActivity {
 		if (fm.getBackStackEntryCount() == 0) {
 			// We re-launched into an existing state,
 			// need to re-populate the back stack.
-			onNotSetup(false);
+			onNotSetup();
 			onShowDownload();
 		}
 		Fragment f;
@@ -201,4 +195,22 @@ public class MailboxActivity extends BriarActivity {
 		showFragment(getSupportFragmentManager(), f, tag, false);
 	}
 
+	private void onUnPaired(boolean tellUserToWipeMailbox) {
+		if (tellUserToWipeMailbox) {
+			showFragment(getSupportFragmentManager(), new BlankFragment(),
+					BlankFragment.TAG);
+			AlertDialog.Builder builder =
+					new AlertDialog.Builder(this, R.style.BriarDialogTheme);
+			builder.setTitle(R.string.mailbox_status_unlink_no_wipe_title);
+			builder.setMessage(R.string.mailbox_status_unlink_no_wipe_message);
+			builder.setNeutralButton(R.string.got_it,
+					(dialog, which) -> dialog.cancel());
+			builder.setOnCancelListener(
+					dialog -> supportFinishAfterTransition());
+			builder.show();
+		} else {
+			supportFinishAfterTransition();
+		}
+	}
+
 }

briar-android/src/main/java/org/briarproject/briar/android/mailbox/MailboxState.java

@@ -5,15 +5,6 @@ import org.briarproject.bramble.api.mailbox.MailboxPairingState;
 class MailboxState {
 
 	static class NotSetup extends MailboxState {
-		final boolean tellUserToWipeMailbox;
-
-		NotSetup() {
-			this(false);
-		}
-
-		NotSetup(boolean tellUserToWipeMailbox) {
-			this.tellUserToWipeMailbox = tellUserToWipeMailbox;
-		}
 	}
 
 	static class ShowDownload extends MailboxState {
@@ -44,4 +35,12 @@ class MailboxState {
 		}
 	}
 
+	static class WasUnpaired extends MailboxState {
+		final boolean tellUserToWipeMailbox;
+
+		WasUnpaired(boolean tellUserToWipeMailbox) {
+			this.tellUserToWipeMailbox = tellUserToWipeMailbox;
+		}
+	}
+
 }

briar-android/src/main/java/org/briarproject/briar/android/mailbox/MailboxViewModel.java

@@ -226,7 +226,7 @@ class MailboxViewModel extends DbViewModel
 		ioExecutor.execute(() -> {
 			try {
 				boolean wasWiped = mailboxManager.unPair();
-				pairingState.postEvent(new MailboxState.NotSetup(!wasWiped));
+				pairingState.postEvent(new MailboxState.WasUnpaired(!wasWiped));
 			} catch (DbException e) {
 				handleException(e);
 			}

briar-android/src/main/java/org/briarproject/briar/android/view/BlankFragment.java

@@ -0,0 +1,12 @@
+package org.briarproject.briar.android.view;
+
+import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
+import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
+
+import androidx.fragment.app.Fragment;
+
+@MethodsNotNullByDefault
+@ParametersNotNullByDefault
+public class BlankFragment extends Fragment {
+	public static final String TAG = BlankFragment.class.getName();
+}