Improve (un)registering FragmentLifecycleCallbacks

to avoid adding it multiple times and ensure proper cleanup

app/src/main/java/org/schabi/newpipe/RouterActivity.java

@@ -32,6 +32,7 @@
 import androidx.core.app.NotificationCompat;
 import androidx.core.app.ServiceCompat;
 import androidx.core.math.MathUtils;
+import androidx.fragment.app.DialogFragment;
 import androidx.fragment.app.Fragment;
 import androidx.fragment.app.FragmentManager;
 import androidx.preference.PreferenceManager;
@@ -113,6 +114,7 @@ public class RouterActivity extends AppCompatActivity {
  private boolean selectionIsDownload = false;
  private boolean selectionIsAddToPlaylist = false;
  private AlertDialog alertDialogChoice = null;
+ private FragmentManager.FragmentLifecycleCallbacks dismissListener = null;
 
  @Override
  protected void onCreate(final Bundle savedInstanceState) {
@@ -142,6 +144,27 @@ protected void onCreate(final Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  Icepick.restoreInstanceState(this, savedInstanceState);
 
+ // FragmentManager will take care to recreate (Playlist|Download)Dialog when screen rotates
+ // We used to .setOnDismissListener(dialog -> finish()); when creating these DialogFragments
+ // but those callbacks won't survive a config change
+ // Try an alternate approach to hook into FragmentManager instead, to that effect
+ // (ref: https://stackoverflow.com/a/44028453)
+ final FragmentManager fm = getSupportFragmentManager();
+ if (dismissListener == null) {
+ dismissListener = new FragmentManager.FragmentLifecycleCallbacks() {
+ @Override
+ public void onFragmentDestroyed(@NonNull final FragmentManager fm,
+ @NonNull final Fragment f) {
+ super.onFragmentDestroyed(fm, f);
+ if (f instanceof DialogFragment && fm.getFragments().isEmpty()) {
+ // No more DialogFragments, we're done
+ finish();
+ }
+ }
+ };
+ }
+ fm.registerFragmentLifecycleCallbacks(dismissListener, false);
+
  if (TextUtils.isEmpty(currentUrl)) {
  currentUrl = getUrl(getIntent());
 
@@ -171,29 +194,10 @@ protected void onSaveInstanceState(@NonNull final Bundle outState) {
  protected void onStart() {
  super.onStart();
 
- // FragmentManager will take care to recreate DialogFragments when screen rotates
- // currently that's namely PlaylistDialog or DownloadDialog
- // We used to .setOnDismissListener(dialog ->finish()); when creating those Dialogs
- // but those callbacks won't survive a config change
- // Try an alternate approach to hook into FragmentManager instead, to that effect
- // (courtesy of https://stackoverflow.com/a/44028453)
- final FragmentManager fm = getSupportFragmentManager();
- fm.registerFragmentLifecycleCallbacks(new FragmentManager.FragmentLifecycleCallbacks() {
- @Override
- public void onFragmentViewDestroyed(@NonNull final FragmentManager fm,
- @NonNull final Fragment f) {
- super.onFragmentViewDestroyed(fm, f);
- if (fm.getFragments().isEmpty()) {
- // No more Dialog, we're done
- finish();
- }
- }
- }, false);
-
  // Don't overlap the DialogFragment after rotating the screen
  // If there's no DialogFragment, we're either starting afresh
  // or we didn't make it to PlaylistDialog or DownloadDialog before the orientation change
- if (fm.getFragments().isEmpty()) {
+ if (getSupportFragmentManager().getFragments().isEmpty()) {
  // Start over from scratch
  handleUrl(currentUrl);
  }
@@ -203,6 +207,9 @@ public void onFragmentViewDestroyed(@NonNull final FragmentManager fm,
  protected void onDestroy() {
  super.onDestroy();
 
+ if (dismissListener != null) {
+ getSupportFragmentManager().unregisterFragmentLifecycleCallbacks(dismissListener);
+ }
  disposables.clear();
  }