Added the duplicate indicator explanation & removed some unnecessary functions

app/src/main/java/org/schabi/newpipe/local/LocalItemListAdapter.java

@@ -11,7 +11,6 @@ import androidx.recyclerview.widget.GridLayoutManager;
 import androidx.recyclerview.widget.RecyclerView;
 
 import org.schabi.newpipe.database.LocalItem;
-import org.schabi.newpipe.database.playlist.PlaylistMetadataEntry;
 import org.schabi.newpipe.database.stream.model.StreamStateEntity;
 import org.schabi.newpipe.local.history.HistoryRecordManager;
 import org.schabi.newpipe.local.holder.LocalItemHolder;
@@ -345,16 +344,6 @@ public class LocalItemListAdapter extends RecyclerView.Adapter<RecyclerView.View
         }
     }
 
-    @Override
-    public long getItemId(final int position) {
-        final LocalItem item = localItems.get(position);
-        if (item != null && item.getLocalItemType() == LocalItem.LocalItemType.
-                PLAYLIST_LOCAL_ITEM) {
-            return ((PlaylistMetadataEntry) item).uid;
-        }
-        return super.getItemId(position);
-    }
-
     public GridLayoutManager.SpanSizeLookup getSpanSizeLookup(final int spanCount) {
         return new GridLayoutManager.SpanSizeLookup() {
             @Override

app/src/main/java/org/schabi/newpipe/local/dialog/PlaylistAppendDialog.java

@@ -61,7 +61,6 @@ public final class PlaylistAppendDialog extends PlaylistDialog {
                 new LocalPlaylistManager(NewPipeDatabase.getInstance(requireContext()));
 
         playlistAdapter = new LocalItemListAdapter(getActivity());
-        playlistAdapter.setHasStableIds(true);
         playlistAdapter.setSelectedListener(selectedItem -> {
             final List<StreamEntity> entities = getStreamEntities();
             if (selectedItem instanceof PlaylistDuplicatesEntry && entities != null) {
@@ -125,8 +124,20 @@ public final class PlaylistAppendDialog extends PlaylistDialog {
             playlistAdapter.clearStreamItemList();
             playlistAdapter.addItems(playlists);
             playlistRecyclerView.setVisibility(View.VISIBLE);
+            setDuplicateIndicatorExplanation(playlists);
         }
     }
+    private void setDuplicateIndicatorExplanation(final List<PlaylistDuplicatesEntry> playlists) {
+        for (final PlaylistDuplicatesEntry entry : playlists) {
+            if (entry.timesStreamIsContained > 0) {
+                final View indicatorExplanation = getView()
+                        .findViewById(R.id.playlist_duplicate);
+                indicatorExplanation.setVisibility(View.VISIBLE);
+                return;
+            }
+        }
+
+    }
 
     private void onPlaylistSelected(@NonNull final LocalPlaylistManager manager,
                                     @NonNull final PlaylistDuplicatesEntry playlist,