convert PlayerHolder to Singleton, handle context within, bugfix ServiceConnection leak

- bugfix: have ServiceConnection created only once!

- select the context within the PlayerHolder to start, stop, bind or unbind the service
  -> we have to make sure the Service is started AND stopped within the same context
  -> so let PlayerHolder be the one to select the context

- remove removeListener() and replace the call with setListener(null)
- Compatibility: use ContextCompat.startForegroundService instead of startService()

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

@@ -823,7 +823,7 @@ public class MainActivity extends AppCompatActivity {
             return;
         }
 
-        if (PlayerHolder.isPlayerOpen()) {
+        if (PlayerHolder.getInstance().isPlayerOpen()) {
             // if the player is already open, no need for a broadcast receiver
             openMiniPlayerIfMissing();
         } else {

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

@@ -453,7 +453,7 @@ public class RouterActivity extends AppCompatActivity {
                 returnList.add(showInfo);
                 returnList.add(videoPlayer);
             } else {
-                final MainPlayer.PlayerType playerType = PlayerHolder.getType();
+                final MainPlayer.PlayerType playerType = PlayerHolder.getInstance().getType();
                 if (capabilities.contains(VIDEO)
                         && PlayerHelper.isAutoplayAllowedByUser(context)
                         && playerType == null || playerType == MainPlayer.PlayerType.VIDEO) {

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

@@ -201,6 +201,7 @@ public final class VideoDetailFragment
     @Nullable
     private MainPlayer playerService;
     private Player player;
+    private PlayerHolder playerHolder = PlayerHolder.getInstance();
 
     /*//////////////////////////////////////////////////////////////////////////
     // Service management
@@ -360,9 +361,9 @@ public final class VideoDetailFragment
         // Stop the service when user leaves the app with double back press
         // if video player is selected. Otherwise unbind
         if (activity.isFinishing() && isPlayerAvailable() && player.videoPlayerSelected()) {
-            PlayerHolder.stopService(App.getApp());
+            playerHolder.stopService();
         } else {
-            PlayerHolder.removeListener();
+            playerHolder.setListener(null);
         }
 
         PreferenceManager.getDefaultSharedPreferences(activity)
@@ -660,10 +661,10 @@ public final class VideoDetailFragment
         });
 
         setupBottomPlayer();
-        if (!PlayerHolder.bound) {
+        if (!playerHolder.bound) {
             setHeightThumbnail();
         } else {
-            PlayerHolder.startService(App.getApp(), false, this);
+            playerHolder.startService(false, this);
         }
     }
 
@@ -1097,7 +1098,7 @@ public final class VideoDetailFragment
 
         // See UI changes while remote playQueue changes
         if (!isPlayerAvailable()) {
-            PlayerHolder.startService(App.getApp(), false, this);
+            playerHolder.startService(false, this);
         }
 
         toggleFullscreenIfInFullscreenMode();
@@ -1123,7 +1124,7 @@ public final class VideoDetailFragment
     private void openNormalBackgroundPlayer(final boolean append) {
         // See UI changes while remote playQueue changes
         if (!isPlayerAvailable()) {
-            PlayerHolder.startService(App.getApp(), false, this);
+            playerHolder.startService(false, this);
         }
 
         final PlayQueue queue = setupPlayQueueForIntent(append);
@@ -1137,7 +1138,7 @@ public final class VideoDetailFragment
 
     private void openMainPlayer() {
         if (!isPlayerServiceAvailable()) {
-            PlayerHolder.startService(App.getApp(), autoPlayEnabled, this);
+            playerHolder.startService(autoPlayEnabled, this);
             return;
         }
         if (currentInfo == null) {
@@ -1155,7 +1156,7 @@ public final class VideoDetailFragment
 
         final Intent playerIntent = NavigationHelper
                 .getPlayerIntent(requireContext(), MainPlayer.class, queue, true, autoPlayEnabled);
-        activity.startService(playerIntent);
+        ContextCompat.startForegroundService(activity, playerIntent);
     }
 
     private void hideMainPlayer() {
@@ -1373,9 +1374,9 @@ public final class VideoDetailFragment
                             bottomSheetBehavior.setState(BottomSheetBehavior.STATE_COLLAPSED);
                         }
                         // Rebound to the service if it was closed via notification or mini player
-                        if (!PlayerHolder.bound) {
+                        if (!playerHolder.bound) {
-                            PlayerHolder.startService(
+                            playerHolder.startService(
-                                    App.getApp(), false, VideoDetailFragment.this);
+                                    false, VideoDetailFragment.this);
                         }
                         break;
                 }
@@ -2119,7 +2120,7 @@ public final class VideoDetailFragment
         if (currentWorker != null) {
             currentWorker.dispose();
         }
-        PlayerHolder.stopService(App.getApp());
+        playerHolder.stopService();
         setInitialData(0, null, "", null);
         currentInfo = null;
         updateOverlayData(null, null, null);

app/src/main/java/org/schabi/newpipe/fragments/list/BaseListFragment.java

@@ -353,7 +353,7 @@ public abstract class BaseListFragment<I, N> extends BaseStateFragment<I>
 
         final List<StreamDialogEntry> entries = new ArrayList<>();
 
-        if (PlayerHolder.getType() != null) {
+        if (PlayerHolder.getInstance().getType() != null) {
             entries.add(StreamDialogEntry.enqueue);
         }
         if (item.getStreamType() == StreamType.AUDIO_STREAM) {

app/src/main/java/org/schabi/newpipe/fragments/list/playlist/PlaylistFragment.java

@@ -144,7 +144,7 @@ public class PlaylistFragment extends BaseListInfoFragment<PlaylistInfo> {
 
         final ArrayList<StreamDialogEntry> entries = new ArrayList<>();
 
-        if (PlayerHolder.getType() != null) {
+        if (PlayerHolder.getInstance().getType() != null) {
             entries.add(StreamDialogEntry.enqueue);
         }
         if (item.getStreamType() == StreamType.AUDIO_STREAM) {

app/src/main/java/org/schabi/newpipe/local/feed/FeedFragment.kt

@@ -331,7 +331,7 @@ class FeedFragment : BaseStateFragment<FeedState>() {
         if (context == null || context.resources == null || activity == null) return
 
         val entries = ArrayList<StreamDialogEntry>()
-        if (PlayerHolder.getType() != null) {
+        if (PlayerHolder.getInstance().getType() != null) {
             entries.add(StreamDialogEntry.enqueue)
         }
         if (item.streamType == StreamType.AUDIO_STREAM) {

app/src/main/java/org/schabi/newpipe/local/history/StatisticsPlaylistFragment.java

@@ -340,7 +340,7 @@ public class StatisticsPlaylistFragment
 
         final ArrayList<StreamDialogEntry> entries = new ArrayList<>();
 
-        if (PlayerHolder.getType() != null) {
+        if (PlayerHolder.getInstance().getType() != null) {
             entries.add(StreamDialogEntry.enqueue);
         }
         if (infoItem.getStreamType() == StreamType.AUDIO_STREAM) {

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

@@ -749,7 +749,7 @@ public class LocalPlaylistFragment extends BaseLocalListFragment<List<PlaylistSt
 
         final ArrayList<StreamDialogEntry> entries = new ArrayList<>();
 
-        if (PlayerHolder.getType() != null) {
+        if (PlayerHolder.getInstance().getType() != null) {
             entries.add(StreamDialogEntry.enqueue);
         }
         if (infoItem.getStreamType() == StreamType.AUDIO_STREAM) {

app/src/main/java/org/schabi/newpipe/player/helper/PlayerHolder.java

@@ -8,6 +8,7 @@ import android.os.IBinder;
 import android.util.Log;
 
 import androidx.annotation.Nullable;
+import androidx.core.content.ContextCompat;
 
 import com.google.android.exoplayer2.ExoPlaybackException;
 import com.google.android.exoplayer2.PlaybackParameters;
@@ -22,18 +23,27 @@ import org.schabi.newpipe.player.event.PlayerServiceExtendedEventListener;
 import org.schabi.newpipe.player.playqueue.PlayQueue;
 
 public final class PlayerHolder {
+
     private PlayerHolder() {
     }
 
-    private static final boolean DEBUG = MainActivity.DEBUG;
+    private static PlayerHolder instance;
-    private static final String TAG = "PlayerHolder";
+    public static synchronized PlayerHolder getInstance() {
+        if (PlayerHolder.instance == null) {
+            PlayerHolder.instance = new PlayerHolder();
+        }
+        return PlayerHolder.instance;
+    }
 
-    private static PlayerServiceExtendedEventListener listener;
+    private final boolean DEBUG = MainActivity.DEBUG;
+    private final String TAG = PlayerHolder.class.getSimpleName();
 
-    private static ServiceConnection serviceConnection;
+    private PlayerServiceExtendedEventListener listener;
-    public static boolean bound;
+
-    private static MainPlayer playerService;
+    private final PlayerServiceConnection serviceConnection = new PlayerServiceConnection();
-    private static Player player;
+    public boolean bound;
+    private MainPlayer playerService;
+    private Player player;
 
     /**
      * Returns the current {@link MainPlayer.PlayerType} of the {@link MainPlayer} service,
@@ -42,26 +52,31 @@ public final class PlayerHolder {
      * @return Current PlayerType
      */
     @Nullable
-    public static MainPlayer.PlayerType getType() {
+    public MainPlayer.PlayerType getType() {
         if (player == null) {
             return null;
         }
         return player.getPlayerType();
     }
 
-    public static boolean isPlaying() {
+    public boolean isPlaying() {
         if (player == null) {
             return false;
         }
         return player.isPlaying();
     }
 
-    public static boolean isPlayerOpen() {
+    public boolean isPlayerOpen() {
         return player != null;
     }
 
-    public static void setListener(final PlayerServiceExtendedEventListener newListener) {
+    public void setListener(@Nullable final PlayerServiceExtendedEventListener newListener) {
         listener = newListener;
+
+        if (listener == null) {
+            return;
+        }
+
         // Force reload data from service
         if (player != null) {
             listener.onServiceConnected(player, playerService, false);
@@ -69,14 +84,15 @@ public final class PlayerHolder {
         }
     }
 
-    public static void removeListener() {
+    // helper to handle context in common place as using the same
-        listener = null;
+    // context to bind/unbind a service is crucial
+    private Context getCommonContext() {
+        return App.getApp();
     }
 
-
+    public void startService(final boolean playAfterConnect,
-    public static void startService(final Context context,
+                             final PlayerServiceExtendedEventListener newListener) {
-                                    final boolean playAfterConnect,
+        final Context context = getCommonContext();
-                                    final PlayerServiceExtendedEventListener newListener) {
         setListener(newListener);
         if (bound) {
             return;
@@ -85,58 +101,65 @@ public final class PlayerHolder {
         // and NullPointerExceptions inside the service because the service will be
         // bound twice. Prevent it with unbinding first
         unbind(context);
-        context.startService(new Intent(context, MainPlayer.class));
+        ContextCompat.startForegroundService(context, new Intent(context, MainPlayer.class));
-        serviceConnection = getServiceConnection(context, playAfterConnect);
+        serviceConnection.doPlayAfterConnect(playAfterConnect);
         bind(context);
     }
 
-    public static void stopService(final Context context) {
+    public void stopService() {
+        final Context context = getCommonContext();
         unbind(context);
         context.stopService(new Intent(context, MainPlayer.class));
     }
 
-    private static ServiceConnection getServiceConnection(final Context context,
+    class PlayerServiceConnection implements ServiceConnection {
-                                                          final boolean playAfterConnect) {
-        return new ServiceConnection() {
-            @Override
-            public void onServiceDisconnected(final ComponentName compName) {
-                if (DEBUG) {
-                    Log.d(TAG, "Player service is disconnected");
-                }
 
-                unbind(context);
+        private boolean playAfterConnect = false;
+
+        public void doPlayAfterConnect(final boolean playAfterConnection) {
+            this.playAfterConnect = playAfterConnection;
+        }
+
+        @Override
+        public void onServiceDisconnected(final ComponentName compName) {
+            if (DEBUG) {
+                Log.d(TAG, "Player service is disconnected");
             }
 
-            @Override
+            final Context context = getCommonContext();
-            public void onServiceConnected(final ComponentName compName, final IBinder service) {
+            unbind(context);
-                if (DEBUG) {
+        }
-                    Log.d(TAG, "Player service is connected");
-                }
-                final MainPlayer.LocalBinder localBinder = (MainPlayer.LocalBinder) service;
 
-                playerService = localBinder.getService();
+        @Override
-                player = localBinder.getPlayer();
+        public void onServiceConnected(final ComponentName compName, final IBinder service) {
-                if (listener != null) {
+            if (DEBUG) {
-                    listener.onServiceConnected(player, playerService, playAfterConnect);
+                Log.d(TAG, "Player service is connected");
-                }
-                startPlayerListener();
             }
-        };
+            final MainPlayer.LocalBinder localBinder = (MainPlayer.LocalBinder) service;
-    }
 
-    private static void bind(final Context context) {
+            playerService = localBinder.getService();
+            player = localBinder.getPlayer();
+            if (listener != null) {
+                listener.onServiceConnected(player, playerService, playAfterConnect);
+            }
+            startPlayerListener();
+        }
+    };
+
+    private void bind(final Context context) {
         if (DEBUG) {
             Log.d(TAG, "bind() called");
         }
 
         final Intent serviceIntent = new Intent(context, MainPlayer.class);
-        bound = context.bindService(serviceIntent, serviceConnection, Context.BIND_AUTO_CREATE);
+        bound = context.bindService(serviceIntent, serviceConnection,
+                Context.BIND_AUTO_CREATE);
         if (!bound) {
             context.unbindService(serviceConnection);
         }
     }
 
-    private static void unbind(final Context context) {
+    private void unbind(final Context context) {
         if (DEBUG) {
             Log.d(TAG, "unbind() called");
         }
@@ -153,21 +176,19 @@ public final class PlayerHolder {
         }
     }
 
-
+    private void startPlayerListener() {
-    private static void startPlayerListener() {
         if (player != null) {
-            player.setFragmentListener(INNER_LISTENER);
+            player.setFragmentListener(internalListener);
         }
     }
 
-    private static void stopPlayerListener() {
+    private void stopPlayerListener() {
         if (player != null) {
-            player.removeFragmentListener(INNER_LISTENER);
+            player.removeFragmentListener(internalListener);
         }
     }
 
-
+    private final PlayerServiceEventListener internalListener =
-    private static final PlayerServiceEventListener INNER_LISTENER =
             new PlayerServiceEventListener() {
                 @Override
                 public void onFullscreenStateChanged(final boolean fullscreen) {
@@ -242,7 +263,7 @@ public final class PlayerHolder {
                     if (listener != null) {
                         listener.onServiceStopped();
                     }
-                    unbind(App.getApp());
+                    unbind(getCommonContext());
                 }
             };
 }

app/src/main/java/org/schabi/newpipe/util/NavigationHelper.java

@@ -349,13 +349,13 @@ public final class NavigationHelper {
                                                final boolean switchingPlayers) {
 
         final boolean autoPlay;
-        @Nullable final MainPlayer.PlayerType playerType = PlayerHolder.getType();
+        @Nullable final MainPlayer.PlayerType playerType = PlayerHolder.getInstance().getType();
         if (playerType == null) {
             // no player open
             autoPlay = PlayerHelper.isAutoplayAllowedByUser(context);
         } else if (switchingPlayers) {
             // switching player to main player
-            autoPlay = PlayerHolder.isPlaying(); // keep play/pause state
+            autoPlay = PlayerHolder.getInstance().isPlaying(); // keep play/pause state
         } else if (playerType == MainPlayer.PlayerType.VIDEO) {
             // opening new stream while already playing in main player
             autoPlay = PlayerHelper.isAutoplayAllowedByUser(context);

app/src/main/java/org/schabi/newpipe/util/StreamDialogEntry.java

@@ -39,7 +39,7 @@ public enum StreamDialogEntry {
      * Info: Add this entry within showStreamDialog.
      */
     enqueue(R.string.enqueue_stream, (fragment, item) -> {
-        final MainPlayer.PlayerType type = PlayerHolder.getType();
+        final MainPlayer.PlayerType type = PlayerHolder.getInstance().getType();
 
         if (type == AUDIO) {
             NavigationHelper.enqueueOnBackgroundPlayer(fragment.getContext(),