Fix playlist select dialog and do some refactoring

app/src/main/java/org/schabi/newpipe/settings/SelectPlaylistFragment.java

@@ -1,7 +1,6 @@
 package org.schabi.newpipe.settings;
 
 import android.app.Activity;
-import android.content.DialogInterface;
 import android.os.Bundle;
 import android.view.LayoutInflater;
 import android.view.View;
@@ -34,6 +33,7 @@ import java.util.List;
 import java.util.Vector;
 
 import io.reactivex.Flowable;
+import io.reactivex.android.schedulers.AndroidSchedulers;
 import io.reactivex.disposables.Disposable;
 
 public class SelectPlaylistFragment extends DialogFragment {
@@ -46,12 +46,11 @@ public class SelectPlaylistFragment extends DialogFragment {
     private final ImageLoader imageLoader = ImageLoader.getInstance();
 
     private OnSelectedListener onSelectedListener = null;
-    private OnCancelListener onCancelListener = null;
 
     private ProgressBar progressBar;
     private TextView emptyView;
     private RecyclerView recyclerView;
-    private Disposable playlistsSubscriber;
+    private Disposable disposable = null;
 
     private List<PlaylistLocalItem> playlists = new Vector<>();
 
@@ -59,10 +58,6 @@ public class SelectPlaylistFragment extends DialogFragment {
         onSelectedListener = listener;
     }
 
-    public void setOnCancelListener(final OnCancelListener listener) {
-        onCancelListener = listener;
-    }
-
     /*//////////////////////////////////////////////////////////////////////////
     // Fragment's Lifecycle
     //////////////////////////////////////////////////////////////////////////*/
@@ -70,15 +65,32 @@ public class SelectPlaylistFragment extends DialogFragment {
     @Override
     public View onCreateView(@NonNull final LayoutInflater inflater, final ViewGroup container,
                              final Bundle savedInstanceState) {
-        final View v =
+        final View v = inflater.inflate(R.layout.select_playlist_fragment, container, false);
-                inflater.inflate(R.layout.select_playlist_fragment, container, false);
+        progressBar = v.findViewById(R.id.progressBar);
         recyclerView = v.findViewById(R.id.items_list);
+        emptyView = v.findViewById(R.id.empty_state_view);
+
         recyclerView.setLayoutManager(new LinearLayoutManager(getContext()));
         final SelectPlaylistAdapter playlistAdapter = new SelectPlaylistAdapter();
         recyclerView.setAdapter(playlistAdapter);
 
-        progressBar = v.findViewById(R.id.progressBar);
+        loadPlaylists();
-        emptyView = v.findViewById(R.id.empty_state_view);
+        return v;
+    }
+
+    @Override
+    public void onDestroy() {
+        super.onDestroy();
+        if (disposable != null) {
+            disposable.dispose();
+        }
+    }
+
+    /*//////////////////////////////////////////////////////////////////////////
+    // Load and display playlists
+    //////////////////////////////////////////////////////////////////////////*/
+
+    private void loadPlaylists() {
         progressBar.setVisibility(View.VISIBLE);
         recyclerView.setVisibility(View.GONE);
         emptyView.setVisibility(View.GONE);
@@ -87,43 +99,36 @@ public class SelectPlaylistFragment extends DialogFragment {
         final LocalPlaylistManager localPlaylistManager = new LocalPlaylistManager(database);
         final RemotePlaylistManager remotePlaylistManager = new RemotePlaylistManager(database);
 
-        playlistsSubscriber = Flowable.combineLatest(localPlaylistManager.getPlaylists(),
+        disposable = Flowable.combineLatest(localPlaylistManager.getPlaylists(),
                 remotePlaylistManager.getPlaylists(), PlaylistLocalItem::merge)
+                .observeOn(AndroidSchedulers.mainThread())
                 .subscribe(this::displayPlaylists, this::onError);
-
-        return v;
     }
 
-    @Override
+    private void displayPlaylists(final List<PlaylistLocalItem> newPlaylists) {
-    public void onDestroy() {
+        playlists = newPlaylists;
-        super.onDestroy();
+        progressBar.setVisibility(View.GONE);
-
+        emptyView.setVisibility(newPlaylists.isEmpty() ? View.VISIBLE : View.GONE);
-        if (playlistsSubscriber != null) {
+        recyclerView.setVisibility(newPlaylists.isEmpty() ? View.GONE : View.VISIBLE);
-            playlistsSubscriber.dispose();
-            playlistsSubscriber = null;
     }
+
+    protected void onError(final Throwable e) {
+        final Activity activity = requireActivity();
+        ErrorActivity.reportError(activity, e, activity.getClass(), null, ErrorActivity.ErrorInfo
+                .make(UserAction.UI_ERROR, "none", "load_playlists", R.string.app_ui_crash));
     }
 
     /*//////////////////////////////////////////////////////////////////////////
     // Handle actions
     //////////////////////////////////////////////////////////////////////////*/
 
-    @Override
-    public void onCancel(final DialogInterface dialogInterface) {
-        super.onCancel(dialogInterface);
-        if (onCancelListener != null) {
-            onCancelListener.onCancel();
-        }
-    }
-
     private void clickedItem(final int position) {
         if (onSelectedListener != null) {
             final LocalItem selectedItem = playlists.get(position);
 
             if (selectedItem instanceof PlaylistMetadataEntry) {
                 final PlaylistMetadataEntry entry = ((PlaylistMetadataEntry) selectedItem);
-                onSelectedListener
+                onSelectedListener.onLocalPlaylistSelected(entry.uid, entry.name);
-                        .onLocalPlaylistSelected(entry.uid, entry.name);
 
             } else if (selectedItem instanceof PlaylistRemoteEntity) {
                 final PlaylistRemoteEntity entry = ((PlaylistRemoteEntity) selectedItem);
@@ -134,31 +139,6 @@ public class SelectPlaylistFragment extends DialogFragment {
         dismiss();
     }
 
-    /*//////////////////////////////////////////////////////////////////////////
-    // Item handling
-    //////////////////////////////////////////////////////////////////////////*/
-
-    private void displayPlaylists(final List<PlaylistLocalItem> newPlaylists) {
-        this.playlists = newPlaylists;
-        progressBar.setVisibility(View.GONE);
-        if (newPlaylists.isEmpty()) {
-            emptyView.setVisibility(View.VISIBLE);
-            return;
-        }
-        recyclerView.setVisibility(View.VISIBLE);
-
-    }
-
-    /*//////////////////////////////////////////////////////////////////////////
-    // Error
-    //////////////////////////////////////////////////////////////////////////*/
-
-    protected void onError(final Throwable e) {
-        final Activity activity = getActivity();
-        ErrorActivity.reportError(activity, e, activity.getClass(), null, ErrorActivity.ErrorInfo
-                .make(UserAction.UI_ERROR, "none", "", R.string.app_ui_crash));
-    }
-
     /*//////////////////////////////////////////////////////////////////////////
     // Interfaces
     //////////////////////////////////////////////////////////////////////////*/
@@ -168,12 +148,9 @@ public class SelectPlaylistFragment extends DialogFragment {
         void onRemotePlaylistSelected(int serviceId, String url, String name);
     }
 
-    public interface OnCancelListener {
-        void onCancel();
-    }
-
     private class SelectPlaylistAdapter
             extends RecyclerView.Adapter<SelectPlaylistAdapter.SelectPlaylistItemHolder> {
+        @NonNull
         @Override
         public SelectPlaylistItemHolder onCreateViewHolder(final ViewGroup parent,
                                                            final int viewType) {
@@ -183,7 +160,8 @@ public class SelectPlaylistFragment extends DialogFragment {
         }
 
         @Override
-        public void onBindViewHolder(final SelectPlaylistItemHolder holder, final int position) {
+        public void onBindViewHolder(@NonNull final SelectPlaylistItemHolder holder,
+                                     final int position) {
             final PlaylistLocalItem selectedItem = playlists.get(position);
 
             if (selectedItem instanceof PlaylistMetadataEntry) {