Fix inconsistency when LocalPlaylist is used as MainFragment tab

Author: TobiGr

app/src/main/java/org/schabi/newpipe/fragments/MainFragment.java

@@ -38,6 +38,7 @@
 import org.schabi.newpipe.databinding.FragmentMainBinding;
 import org.schabi.newpipe.error.ErrorUtil;
 import org.schabi.newpipe.extractor.exceptions.ExtractionException;
+import org.schabi.newpipe.local.playlist.LocalPlaylistFragment;
 import org.schabi.newpipe.settings.tabs.Tab;
 import org.schabi.newpipe.settings.tabs.TabsManager;
 import org.schabi.newpipe.util.NavigationHelper;
@@ -217,6 +218,12 @@ private void updateTitleForTab(final int tabPosition) {
         setTitle(tabsList.get(tabPosition).getTabName(requireContext()));
     }
 
+    public void commitPlaylistTabs() {
+        pagerAdapter.getLocalPlaylistFragments()
+                .stream()
+                .forEach(LocalPlaylistFragment::commitChanges);
+    }
+
     private void updateTabLayoutPosition() {
         final ScrollableTabLayout tabLayout = binding.mainTabLayout;
         final ViewPager viewPager = binding.pager;
@@ -268,10 +275,18 @@ public void onTabReselected(final TabLayout.Tab tab) {
         updateTitleForTab(tab.getPosition());
     }
 
-    private static final class SelectedTabsPagerAdapter
+    public static final class SelectedTabsPagerAdapter
             extends FragmentStatePagerAdapterMenuWorkaround {
         private final Context context;
         private final List<Tab> internalTabsList;
+        /**
+         * Keep reference to LocalPlaylistFragments, because their data can be modified by the user
+         * during runtime and changes are not committed immediately. However, in some cases,
+         * the changes need to be committed immediately by calling
+         * {@link LocalPlaylistFragment#commitChanges()}.
+         * The fragments are removed when {@link LocalPlaylistFragment#onDestroy()} is called.
+         */
+        private final List<LocalPlaylistFragment> localPlaylistFragments = new ArrayList<>();
 
         private SelectedTabsPagerAdapter(final Context context,
                                          final FragmentManager fragmentManager,
@@ -298,9 +313,17 @@ public Fragment getItem(final int position) {
                 ((BaseFragment) fragment).useAsFrontPage(true);
             }
 
+            if (fragment instanceof LocalPlaylistFragment) {
+                localPlaylistFragments.add((LocalPlaylistFragment) fragment);
+            }
+
             return fragment;
         }
 
+        public List<LocalPlaylistFragment> getLocalPlaylistFragments() {
+            return localPlaylistFragments;
+        }
+
         @Override
         public int getItemPosition(@NonNull final Object object) {
             // Causes adapter to reload all Fragments when

app/src/main/java/org/schabi/newpipe/fragments/detail/VideoDetailFragment.java

@@ -85,6 +85,7 @@
 import org.schabi.newpipe.fragments.BackPressable;
 import org.schabi.newpipe.fragments.BaseStateFragment;
 import org.schabi.newpipe.fragments.EmptyFragment;
+import org.schabi.newpipe.fragments.MainFragment;
 import org.schabi.newpipe.fragments.list.comments.CommentsFragment;
 import org.schabi.newpipe.fragments.list.videos.RelatedItemsFragment;
 import org.schabi.newpipe.ktx.AnimationType;
@@ -482,6 +483,8 @@ private void setOnClickListeners() {
                 // commit previous pending changes to database
                 if (fragment instanceof LocalPlaylistFragment) {
                     ((LocalPlaylistFragment) fragment).commitChanges();
+                } else if (fragment instanceof MainFragment) {
+                    ((MainFragment) fragment).commitPlaylistTabs();
                 }
 
                 disposables.add(PlaylistDialog.createCorrespondingDialog(requireContext(),

app/src/main/java/org/schabi/newpipe/local/playlist/LocalPlaylistFragment.java

@@ -41,6 +41,7 @@
 import org.schabi.newpipe.error.ErrorInfo;
 import org.schabi.newpipe.error.UserAction;
 import org.schabi.newpipe.extractor.stream.StreamInfoItem;
+import org.schabi.newpipe.fragments.MainFragment;
 import org.schabi.newpipe.fragments.list.playlist.PlaylistControlViewHolder;
 import org.schabi.newpipe.info_list.dialog.InfoItemDialog;
 import org.schabi.newpipe.info_list.dialog.StreamDialogDefaultEntry;
@@ -71,7 +72,7 @@
 
 public class LocalPlaylistFragment extends BaseLocalListFragment<List<PlaylistStreamEntry>, Void>
         implements PlaylistControlViewHolder {
-    // Save the list 10 seconds after the last change occurred
+    /** Save the list 10 seconds after the last change occurred. */
     private static final long SAVE_DEBOUNCE_MILLIS = 10000;
     private static final int MINIMUM_INITIAL_DRAG_VELOCITY = 12;
     @State
@@ -92,13 +93,20 @@ public class LocalPlaylistFragment extends BaseLocalListFragment<List<PlaylistSt
     private PublishSubject<Long> debouncedSaveSignal;
     private CompositeDisposable disposables;
 
-    /* Has the playlist been fully loaded from db */
+    /** Whether the playlist has been fully loaded from db. */
     private AtomicBoolean isLoadingComplete;
-    /* Has the playlist been modified (e.g. items reordered or deleted) */
+    /** Whether the playlist has been modified (e.g. items reordered or deleted) */
     private AtomicBoolean isModified;
-    /* Flag to prevent simultaneous rewrites of the playlist */
+    /** Flag to prevent simultaneous rewrites of the playlist. */
     private boolean isRewritingPlaylist = false;
 
+    /**
+     * The pager adapter that the fragment is created from when it is used as frontpage, i.e.
+     * {@link #useAsFrontPage} is {@link true}.
+     */
+    @Nullable
+    private MainFragment.SelectedTabsPagerAdapter tabsPagerAdapter = null;
+
     public static LocalPlaylistFragment getInstance(final long playlistId, final String name) {
         final LocalPlaylistFragment instance = new LocalPlaylistFragment();
         instance.setInitialData(playlistId, name);
@@ -158,9 +166,11 @@ protected ViewBinding getListHeader() {
         return headerBinding;
     }
 
-    // Commit changes immediately when the user turns to the player.
-    // Delete operations will be committed to ensure that the database
-    // is up to date when the user adds the just deleted stream by the player.
+    /**
+     * <p>Commit changes immediately if the playlist has been modified.</p>
+     *  Delete operations and other modifications will be committed to ensure that the database
+     *  is up to date, e.g. when the user adds the just deleted stream from another fragment.
+     */
     public void commitChanges() {
         if (isModified != null && isModified.get()) {
             saveImmediate();
@@ -300,6 +310,9 @@ public void onDestroy() {
         if (disposables != null) {
             disposables.dispose();
         }
+        if (tabsPagerAdapter != null) {
+            tabsPagerAdapter.getLocalPlaylistFragments().remove(this);
+        }
 
         debouncedSaveSignal = null;
         playlistManager = null;
@@ -886,5 +899,10 @@ private void createShareConfirmationDialog() {
                 )
                 .show();
     }
+
+    public void setTabsPagerAdapter(
+            @Nullable final MainFragment.SelectedTabsPagerAdapter tabsPagerAdapter) {
+        this.tabsPagerAdapter = tabsPagerAdapter;
+    }
 }