Merge pull request #12337 from Profpatsch/video-detail-fragment-kotlin-conversion

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

@@ -849,7 +849,7 @@ public class MainActivity extends AppCompatActivity {
             return;
         }
 
-        if (PlayerHolder.getInstance().isPlayerOpen()) {
+        if (PlayerHolder.INSTANCE.isPlayerOpen()) {
             // if the player is already open, no need for a broadcast receiver
             openMiniPlayerIfMissing();
         } else {
@@ -859,7 +859,7 @@ public class MainActivity extends AppCompatActivity {
                 public void onReceive(final Context context, final Intent intent) {
                     if (Objects.equals(intent.getAction(),
                             VideoDetailFragment.ACTION_PLAYER_STARTED)
-                            && PlayerHolder.getInstance().isPlayerOpen()) {
+                            && PlayerHolder.INSTANCE.isPlayerOpen()) {
                         openMiniPlayerIfMissing();
                         // At this point the player is added 100%, we can unregister. Other actions
                         // are useless since the fragment will not be removed after that.
@@ -874,7 +874,7 @@ public class MainActivity extends AppCompatActivity {
 
             // If the PlayerHolder is not bound yet, but the service is running, try to bind to it.
             // Once the connection is established, the ACTION_PLAYER_STARTED will be sent.
-            PlayerHolder.getInstance().tryBindIfNeeded(this);
+            PlayerHolder.INSTANCE.tryBindIfNeeded(this);
         }
     }
 

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

@@ -701,7 +701,7 @@ public class RouterActivity extends AppCompatActivity {
         }
 
         // ...the player is not running or in normal Video-mode/type
-        final PlayerType playerType = PlayerHolder.getInstance().getType();
+        final PlayerType playerType = PlayerHolder.INSTANCE.getType();
         return playerType == null || playerType == PlayerType.MAIN;
     }
 

app/src/main/java/org/schabi/newpipe/info_list/dialog/InfoItemDialog.java

@@ -252,7 +252,7 @@ public final class InfoItemDialog {
          * @return the current {@link Builder} instance
          */
         public Builder addEnqueueEntriesIfNeeded() {
-            final PlayerHolder holder = PlayerHolder.getInstance();
+            final PlayerHolder holder = PlayerHolder.INSTANCE;
             if (holder.isPlayQueueReady()) {
                 addEntry(StreamDialogDefaultEntry.ENQUEUE);
 

app/src/main/java/org/schabi/newpipe/player/PlayQueueActivity.java

@@ -97,8 +97,48 @@ public final class PlayQueueActivity extends AppCompatActivity
             getSupportActionBar().setTitle(R.string.title_activity_play_queue);
         }
 
-        serviceConnection = getServiceConnection();
+        serviceConnection = new ServiceConnection() {
-        bind();
+            @Override
+            public void onServiceDisconnected(final ComponentName name) {
+                Log.d(TAG, "Player service is disconnected");
+            }
+
+            @Override
+            public void onServiceConnected(final ComponentName name, final IBinder binder) {
+                Log.d(TAG, "Player service is connected");
+
+                if (binder instanceof PlayerService.LocalBinder) {
+                    @Nullable final PlayerService s =
+                            ((PlayerService.LocalBinder) binder).getService();
+                    if (s == null) {
+                        throw new IllegalArgumentException(
+                                "PlayerService.LocalBinder.getService() must never be"
+                                        + "null after the service connects");
+                    }
+                    player = s.getPlayer();
+                }
+
+                if (player == null || player.getPlayQueue() == null || player.exoPlayerIsNull()) {
+                    unbind();
+                } else {
+                    onQueueUpdate(player.getPlayQueue());
+                    buildComponents();
+                    if (player != null) {
+                        player.setActivityListener(PlayQueueActivity.this);
+                    }
+                }
+            }
+        };
+
+        // Note: this code should not really exist, and PlayerHolder should be used instead, but
+        // it will be rewritten when NewPlayer will replace the current player.
+        final Intent bindIntent = new Intent(this, PlayerService.class);
+        bindIntent.setAction(PlayerService.BIND_PLAYER_HOLDER_ACTION);
+        final boolean success = bindService(bindIntent, serviceConnection, BIND_AUTO_CREATE);
+        if (!success) {
+            unbindService(serviceConnection);
+        }
+        serviceBound = success;
     }
 
     @Override
@@ -180,19 +220,6 @@ public final class PlayQueueActivity extends AppCompatActivity
 
     ////////////////////////////////////////////////////////////////////////////
     // Service Connection
-    ////////////////////////////////////////////////////////////////////////////
-
-    private void bind() {
-        // Note: this code should not really exist, and PlayerHolder should be used instead, but
-        // it will be rewritten when NewPlayer will replace the current player.
-        final Intent bindIntent = new Intent(this, PlayerService.class);
-        bindIntent.setAction(PlayerService.BIND_PLAYER_HOLDER_ACTION);
-        final boolean success = bindService(bindIntent, serviceConnection, BIND_AUTO_CREATE);
-        if (!success) {
-            unbindService(serviceConnection);
-        }
-        serviceBound = success;
-    }
 
     private void unbind() {
         if (serviceBound) {
@@ -212,41 +239,6 @@ public final class PlayQueueActivity extends AppCompatActivity
         }
     }
 
-    private ServiceConnection getServiceConnection() {
-        return new ServiceConnection() {
-            @Override
-            public void onServiceDisconnected(final ComponentName name) {
-                Log.d(TAG, "Player service is disconnected");
-            }
-
-            @Override
-            public void onServiceConnected(final ComponentName name, final IBinder binder) {
-                Log.d(TAG, "Player service is connected");
-
-                if (binder instanceof PlayerService.LocalBinder) {
-                    @Nullable final PlayerService s =
-                            ((PlayerService.LocalBinder) binder).getService();
-                    if (s == null) {
-                        throw new IllegalArgumentException(
-                                "PlayerService.LocalBinder.getService() must never be"
-                                        + "null after the service connects");
-                    }
-                    player = s.getPlayer();
-                }
-
-                if (player == null || player.getPlayQueue() == null || player.exoPlayerIsNull()) {
-                    unbind();
-                } else {
-                    onQueueUpdate(player.getPlayQueue());
-                    buildComponents();
-                    if (player != null) {
-                        player.setActivityListener(PlayQueueActivity.this);
-                    }
-                }
-            }
-        };
-    }
-
     ////////////////////////////////////////////////////////////////////////////
     // Component Building
     ////////////////////////////////////////////////////////////////////////////

app/src/main/java/org/schabi/newpipe/player/Player.java

@@ -133,6 +133,10 @@ import io.reactivex.rxjava3.disposables.CompositeDisposable;
 import io.reactivex.rxjava3.disposables.Disposable;
 import io.reactivex.rxjava3.disposables.SerialDisposable;
 
+/**
+ * The ExoPlayer wrapper & Player business logic.
+ * Only instantiated once, from {@link PlayerService}.
+ */
 public final class Player implements PlaybackListener, Listener {
     public static final boolean DEBUG = MainActivity.DEBUG;
     public static final String TAG = Player.class.getSimpleName();
@@ -473,22 +477,23 @@ public final class Player implements PlaybackListener, Listener {
     }
 
     private void initUIsForCurrentPlayerType() {
-        if ((UIs.getOpt(MainPlayerUi.class).isPresent() && playerType == PlayerType.MAIN)
+        if ((UIs.get(MainPlayerUi.class) != null && playerType == PlayerType.MAIN)
-                || (UIs.getOpt(PopupPlayerUi.class).isPresent()
+                || (UIs.get(PopupPlayerUi.class) != null
                     && playerType == PlayerType.POPUP)) {
             // correct UI already in place
             return;
         }
 
         // try to reuse binding if possible
-        final PlayerBinding binding = UIs.getOpt(VideoPlayerUi.class).map(VideoPlayerUi::getBinding)
+        @Nullable final VideoPlayerUi ui = UIs.get(VideoPlayerUi.class);
-                .orElseGet(() -> {
+        final PlayerBinding binding;
-                    if (playerType == PlayerType.AUDIO) {
+        if (ui != null) {
-                        return null;
+            binding = ui.getBinding();
-                    } else {
+        } else if (playerType == PlayerType.AUDIO) {
-                        return PlayerBinding.inflate(LayoutInflater.from(context));
+            binding = null;
-                    }
+        } else {
-                });
+            binding = PlayerBinding.inflate(LayoutInflater.from(context));
+        }
 
         switch (playerType) {
             case MAIN:

app/src/main/java/org/schabi/newpipe/player/PlayerService.kt

@@ -37,7 +37,6 @@ import org.schabi.newpipe.player.notification.NotificationPlayerUi
 import org.schabi.newpipe.util.Localization
 import org.schabi.newpipe.util.ThemeHelper
 import java.lang.ref.WeakReference
-import java.util.function.BiConsumer
 import java.util.function.Consumer
 
 /**
@@ -47,13 +46,13 @@ class PlayerService : MediaBrowserServiceCompat() {
     // These objects are used to cleanly separate the Service implementation (in this file) and the
     // media browser and playback preparer implementations. At the moment the playback preparer is
     // only used in conjunction with the media browser.
-    private var mediaBrowserImpl: MediaBrowserImpl? = null
+    private lateinit var mediaBrowserImpl: MediaBrowserImpl
-    private var mediaBrowserPlaybackPreparer: MediaBrowserPlaybackPreparer? = null
+    private lateinit var mediaBrowserPlaybackPreparer: MediaBrowserPlaybackPreparer
 
     // these are instantiated in onCreate() as per
     // https://developer.android.com/training/cars/media#browser_workflow
-    private var mediaSession: MediaSessionCompat? = null
+    private lateinit var mediaSession: MediaSessionCompat
-    private var sessionConnector: MediaSessionConnector? = null
+    private lateinit var sessionConnector: MediaSessionConnector
 
     /**
      * @return the current active player instance. May be null, since the player service can outlive
@@ -68,7 +67,7 @@ class PlayerService : MediaBrowserServiceCompat() {
      * The parameter taken by this [Consumer] can be null to indicate the player is being
      * stopped.
      */
-    private var onPlayerStartedOrStopped: Consumer<Player?>? = null
+    private var onPlayerStartedOrStopped: ((player: Player?) -> Unit)? = null
 
     //region Service lifecycle
     override fun onCreate() {
@@ -80,14 +79,7 @@ class PlayerService : MediaBrowserServiceCompat() {
         Localization.assureCorrectAppLanguage(this)
         ThemeHelper.setTheme(this)
 
-        mediaBrowserImpl = MediaBrowserImpl(
+        mediaBrowserImpl = MediaBrowserImpl(this, this::notifyChildrenChanged)
-            this,
-            Consumer { parentId: String ->
-                this.notifyChildrenChanged(
-                    parentId
-                )
-            }
-        )
 
         // see https://developer.android.com/training/cars/media#browser_workflow
         val session = MediaSessionCompat(this, "MediaSessionPlayerServ")
@@ -98,17 +90,10 @@ class PlayerService : MediaBrowserServiceCompat() {
         connector.setMetadataDeduplicationEnabled(true)
 
         mediaBrowserPlaybackPreparer = MediaBrowserPlaybackPreparer(
-            this,
+            context = this,
-            BiConsumer { message: String, code: Int ->
+            setMediaSessionError = connector::setCustomErrorMessage,
-                connector.setCustomErrorMessage(
+            clearMediaSessionError = { connector.setCustomErrorMessage(null) },
-                    message,
+            onPrepare = { player?.onPrepare() }
-                    code
-                )
-            },
-            Runnable { connector.setCustomErrorMessage(null) },
-            Consumer { playWhenReady: Boolean? ->
-                player?.onPrepare()
-            }
         )
         connector.setPlaybackPreparer(mediaBrowserPlaybackPreparer)
 
@@ -125,11 +110,8 @@ class PlayerService : MediaBrowserServiceCompat() {
         if (DEBUG) {
             Log.d(
                 TAG,
-                (
+                "onStartCommand() called with: intent = [$intent], extras = [${
-                    "onStartCommand() called with: intent = [" + intent +
+                intent.extras.toDebugString()}], flags = [$flags], startId = [$startId]"
-                        "], extras = [" + intent.extras.toDebugString() +
-                        "], flags = [" + flags + "], startId = [" + startId + "]"
-                    )
             )
         }
 
@@ -140,7 +122,7 @@ class PlayerService : MediaBrowserServiceCompat() {
             val playerWasNull = (player == null)
             if (playerWasNull) {
                 // make sure the player exists, in case the service was resumed
-                player = Player(this, mediaSession!!, sessionConnector!!)
+                player = Player(this, mediaSession, sessionConnector)
             }
 
             // Be sure that the player notification is set and the service is started in foreground,
@@ -150,35 +132,29 @@ class PlayerService : MediaBrowserServiceCompat() {
             // no one already and starting the service in foreground should not create any issues.
             // If the service is already started in foreground, requesting it to be started
             // shouldn't do anything.
-            player!!.UIs().get(NotificationPlayerUi::class.java)
+            player?.UIs()?.get(NotificationPlayerUi::class)?.createNotificationAndStartForeground()
-                ?.createNotificationAndStartForeground()
 
-            val startedOrStopped = onPlayerStartedOrStopped
+            if (playerWasNull) {
-            if (playerWasNull && startedOrStopped != null) {
                 // notify that a new player was created (but do it after creating the foreground
                 // notification just to make sure we don't incur, due to slowness, in
                 // "Context.startForegroundService() did not then call Service.startForeground()")
-                startedOrStopped.accept(player)
+                onPlayerStartedOrStopped?.invoke(player)
             }
         }
 
         val p = player
-        if (Intent.ACTION_MEDIA_BUTTON == intent.action &&
+        if (Intent.ACTION_MEDIA_BUTTON == intent.action && p?.playQueue == null) {
-            (p == null || p.playQueue == null)
+            // No need to process media button's actions if the player is not working, otherwise
-        ) {
+            // the player service would strangely start with nothing to play
-            /*
+            // Stop the service in this case, which will be removed from the foreground and its
-            No need to process media button's actions if the player is not working, otherwise
+            // notification cancelled in its destruction
-            the player service would strangely start with nothing to play
-            Stop the service in this case, which will be removed from the foreground and its
-            notification cancelled in its destruction
-             */
             destroyPlayerAndStopService()
             return START_NOT_STICKY
         }
 
         if (p != null) {
             p.handleIntent(intent)
-            p.UIs().get(MediaSessionPlayerUi::class.java)
+            p.UIs().get(MediaSessionPlayerUi::class)
                 ?.handleMediaButtonIntent(intent)
         }
 
@@ -218,22 +194,22 @@ class PlayerService : MediaBrowserServiceCompat() {
 
         cleanup()
 
-        mediaBrowserPlaybackPreparer?.dispose()
+        mediaBrowserPlaybackPreparer.dispose()
-        mediaSession?.release()
+        mediaSession.release()
-        mediaBrowserImpl?.dispose()
+        mediaBrowserImpl.dispose()
     }
 
     private fun cleanup() {
         val p = player
         if (p != null) {
             // notify that the player is being destroyed
-            onPlayerStartedOrStopped?.accept(null)
+            onPlayerStartedOrStopped?.invoke(null)
             p.saveAndShutdown()
             player = null
         }
 
         // Should already be handled by MediaSessionPlayerUi, but just to be sure.
-        mediaSession?.setActive(false)
+        mediaSession.setActive(false)
 
         // Should already be handled by NotificationUtil.cancelNotificationAndStopForeground() in
         // NotificationPlayerUi, but let's make sure that the foreground service is stopped.
@@ -273,29 +249,27 @@ class PlayerService : MediaBrowserServiceCompat() {
         if (DEBUG) {
             Log.d(
                 TAG,
-                (
+                "onBind() called with: intent = [$intent], extras = [${
-                    "onBind() called with: intent = [" + intent +
+                intent.extras.toDebugString()}]"
-                        "], extras = [" + intent.extras.toDebugString() + "]"
-                    )
             )
         }
 
-        if (BIND_PLAYER_HOLDER_ACTION == intent.action) {
+        return if (BIND_PLAYER_HOLDER_ACTION == intent.action) {
             // Note that this binder might be reused multiple times while the service is alive, even
             // after unbind() has been called: https://stackoverflow.com/a/8794930 .
-            return mBinder
+            mBinder
         } else if (SERVICE_INTERFACE == intent.action) {
             // MediaBrowserService also uses its own binder, so for actions related to the media
             // browser service, pass the onBind to the superclass.
-            return super.onBind(intent)
+            super.onBind(intent)
         } else {
             // This is an unknown request, avoid returning any binder to not leak objects.
-            return null
+            null
         }
     }
 
     class LocalBinder internal constructor(playerService: PlayerService) : Binder() {
-        private val playerService = WeakReference<PlayerService?>(playerService)
+        private val playerService = WeakReference(playerService)
 
         val service: PlayerService?
             get() = playerService.get()
@@ -307,9 +281,9 @@ class PlayerService : MediaBrowserServiceCompat() {
      * by the [Consumer] can be null to indicate that the player is stopping.
      * @param listener the listener to set or unset
      */
-    fun setPlayerListener(listener: Consumer<Player?>?) {
+    fun setPlayerListener(listener: ((player: Player?) -> Unit)?) {
         this.onPlayerStartedOrStopped = listener
-        listener?.accept(player)
+        listener?.invoke(player)
     }
 
     //endregion
@@ -320,14 +294,14 @@ class PlayerService : MediaBrowserServiceCompat() {
         rootHints: Bundle?
     ): BrowserRoot? {
         // TODO check if the accessing package has permission to view data
-        return mediaBrowserImpl?.onGetRoot(clientPackageName, clientUid, rootHints)
+        return mediaBrowserImpl.onGetRoot(clientPackageName, clientUid, rootHints)
     }
 
     override fun onLoadChildren(
         parentId: String,
         result: Result<List<MediaBrowserCompat.MediaItem>>
     ) {
-        mediaBrowserImpl?.onLoadChildren(parentId, result)
+        mediaBrowserImpl.onLoadChildren(parentId, result)
     }
 
     override fun onSearch(
@@ -335,7 +309,7 @@ class PlayerService : MediaBrowserServiceCompat() {
         extras: Bundle?,
         result: Result<List<MediaBrowserCompat.MediaItem>>
     ) {
-        mediaBrowserImpl?.onSearch(query, result)
+        mediaBrowserImpl.onSearch(query, result)
     } //endregion
 
     companion object {

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

@@ -1,385 +0,0 @@
-package org.schabi.newpipe.player.helper;
-
-import android.content.ComponentName;
-import android.content.Context;
-import android.content.Intent;
-import android.content.ServiceConnection;
-import android.os.IBinder;
-import android.util.Log;
-
-import androidx.annotation.Nullable;
-import androidx.core.content.ContextCompat;
-
-import com.google.android.exoplayer2.PlaybackException;
-import com.google.android.exoplayer2.PlaybackParameters;
-
-import org.schabi.newpipe.App;
-import org.schabi.newpipe.MainActivity;
-import org.schabi.newpipe.extractor.stream.StreamInfo;
-import org.schabi.newpipe.player.PlayerService;
-import org.schabi.newpipe.player.Player;
-import org.schabi.newpipe.player.PlayerType;
-import org.schabi.newpipe.player.event.PlayerServiceEventListener;
-import org.schabi.newpipe.player.event.PlayerServiceExtendedEventListener;
-import org.schabi.newpipe.player.playqueue.PlayQueue;
-import org.schabi.newpipe.util.NavigationHelper;
-
-import java.util.Optional;
-import java.util.function.Consumer;
-
-public final class PlayerHolder {
-
-    private PlayerHolder() {
-    }
-
-    private static PlayerHolder instance;
-    public static synchronized PlayerHolder getInstance() {
-        if (PlayerHolder.instance == null) {
-            PlayerHolder.instance = new PlayerHolder();
-        }
-        return PlayerHolder.instance;
-    }
-
-    private static final boolean DEBUG = MainActivity.DEBUG;
-    private static final String TAG = PlayerHolder.class.getSimpleName();
-
-    @Nullable private PlayerServiceExtendedEventListener listener;
-
-    private final PlayerServiceConnection serviceConnection = new PlayerServiceConnection();
-    private boolean bound;
-    @Nullable private PlayerService playerService;
-
-    private Optional<Player> getPlayer() {
-        return Optional.ofNullable(playerService)
-                .flatMap(s -> Optional.ofNullable(s.getPlayer()));
-    }
-
-    private Optional<PlayQueue> getPlayQueue() {
-        // player play queue might be null e.g. while player is starting
-        return getPlayer().flatMap(p -> Optional.ofNullable(p.getPlayQueue()));
-    }
-
-    /**
-     * Returns the current {@link PlayerType} of the {@link PlayerService} service,
-     * otherwise `null` if no service is running.
-     *
-     * @return Current PlayerType
-     */
-    @Nullable
-    public PlayerType getType() {
-        return getPlayer().map(Player::getPlayerType).orElse(null);
-    }
-
-    public boolean isPlaying() {
-        return getPlayer().map(Player::isPlaying).orElse(false);
-    }
-
-    public boolean isPlayerOpen() {
-        return getPlayer().isPresent();
-    }
-
-    /**
-     * Use this method to only allow the user to manipulate the play queue (e.g. by enqueueing via
-     * the stream long press menu) when there actually is a play queue to manipulate.
-     * @return true only if the player is open and its play queue is ready (i.e. it is not null)
-     */
-    public boolean isPlayQueueReady() {
-        return getPlayQueue().isPresent();
-    }
-
-    public boolean isBound() {
-        return bound;
-    }
-
-    public int getQueueSize() {
-        return getPlayQueue().map(PlayQueue::size).orElse(0);
-    }
-
-    public int getQueuePosition() {
-        return getPlayQueue().map(PlayQueue::getIndex).orElse(0);
-    }
-
-    public void setListener(@Nullable final PlayerServiceExtendedEventListener newListener) {
-        listener = newListener;
-
-        if (listener == null) {
-            return;
-        }
-
-        // Force reload data from service
-        if (playerService != null) {
-            listener.onServiceConnected(playerService);
-            startPlayerListener();
-            // ^ will call listener.onPlayerConnected() down the line if there is an active player
-        }
-    }
-
-    // helper to handle context in common place as using the same
-    // context to bind/unbind a service is crucial
-    private Context getCommonContext() {
-        return App.getInstance();
-    }
-
-    /**
-     * Connect to (and if needed start) the {@link PlayerService}
-     * and bind {@link PlayerServiceConnection} to it.
-     * If the service is already started, only set the listener.
-     * @param playAfterConnect If this holder’s service was already started,
-     *                         start playing immediately
-     * @param newListener set this listener
-     * */
-    public void startService(final boolean playAfterConnect,
-                             final PlayerServiceExtendedEventListener newListener) {
-        if (DEBUG) {
-            Log.d(TAG, "startService() called with playAfterConnect=" + playAfterConnect);
-        }
-        final Context context = getCommonContext();
-        setListener(newListener);
-        if (bound) {
-            return;
-        }
-        // startService() can be called concurrently and it will give a random crashes
-        // and NullPointerExceptions inside the service because the service will be
-        // bound twice. Prevent it with unbinding first
-        unbind(context);
-        final Intent intent = new Intent(context, PlayerService.class);
-        intent.putExtra(PlayerService.SHOULD_START_FOREGROUND_EXTRA, true);
-        ContextCompat.startForegroundService(context, intent);
-        serviceConnection.doPlayAfterConnect(playAfterConnect);
-        bind(context);
-    }
-
-    public void stopService() {
-        if (DEBUG) {
-            Log.d(TAG, "stopService() called");
-        }
-        if (playerService != null) {
-            playerService.destroyPlayerAndStopService();
-        }
-        final Context context = getCommonContext();
-        unbind(context);
-        // destroyPlayerAndStopService() already runs the next line of code, but run it again just
-        // to make sure to stop the service even if playerService is null by any chance.
-        context.stopService(new Intent(context, PlayerService.class));
-    }
-
-    class PlayerServiceConnection implements ServiceConnection {
-
-        private boolean playAfterConnect = false;
-
-        /**
-         * @param playAfterConnection Sets the value of `playAfterConnect` to pass to the {@link
-         * PlayerServiceExtendedEventListener#onPlayerConnected(Player, boolean)} the next time it
-         * is called. The value of `playAfterConnect` will be reset to false after that.
-         */
-        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");
-            }
-
-            final Context context = getCommonContext();
-            unbind(context);
-        }
-
-        @Override
-        public void onServiceConnected(final ComponentName compName, final IBinder service) {
-            if (DEBUG) {
-                Log.d(TAG, "Player service is connected");
-            }
-            final PlayerService.LocalBinder localBinder = (PlayerService.LocalBinder) service;
-
-            @Nullable final PlayerService s = localBinder.getService();
-            if (s == null) {
-                throw new IllegalArgumentException(
-                        "PlayerService.LocalBinder.getService() must never be"
-                                + "null after the service connects");
-            }
-            playerService = s;
-            if (listener != null) {
-                listener.onServiceConnected(s);
-                getPlayer().ifPresent(p -> listener.onPlayerConnected(p, playAfterConnect));
-            }
-            startPlayerListener();
-            // ^ will call listener.onPlayerConnected() down the line if there is an active player
-
-            // notify the main activity that binding the service has completed, so that it can
-            // open the bottom mini-player
-            NavigationHelper.sendPlayerStartedEvent(s);
-        }
-    }
-
-    private void bind(final Context context) {
-        if (DEBUG) {
-            Log.d(TAG, "bind() called");
-        }
-        // BIND_AUTO_CREATE starts the service if it's not already running
-        bound = bind(context, Context.BIND_AUTO_CREATE);
-        if (!bound) {
-            context.unbindService(serviceConnection);
-        }
-    }
-
-    public void tryBindIfNeeded(final Context context) {
-        if (!bound) {
-            // flags=0 means the service will not be started if it does not already exist. In this
-            // case the return value is not useful, as a value of "true" does not really indicate
-            // that the service is going to be bound.
-            bind(context, 0);
-        }
-    }
-
-    private boolean bind(final Context context, final int flags) {
-        final Intent serviceIntent = new Intent(context, PlayerService.class);
-        serviceIntent.setAction(PlayerService.BIND_PLAYER_HOLDER_ACTION);
-        return context.bindService(serviceIntent, serviceConnection, flags);
-    }
-
-    private void unbind(final Context context) {
-        if (DEBUG) {
-            Log.d(TAG, "unbind() called");
-        }
-
-        if (bound) {
-            context.unbindService(serviceConnection);
-            bound = false;
-            stopPlayerListener();
-            playerService = null;
-            if (listener != null) {
-                listener.onPlayerDisconnected();
-                listener.onServiceDisconnected();
-            }
-        }
-    }
-
-    private void startPlayerListener() {
-        if (playerService != null) {
-            // setting the player listener will take care of calling relevant callbacks if the
-            // player in the service is (not) already active, also see playerStateListener below
-            playerService.setPlayerListener(playerStateListener);
-        }
-        getPlayer().ifPresent(p -> p.setFragmentListener(internalListener));
-    }
-
-    private void stopPlayerListener() {
-        if (playerService != null) {
-            playerService.setPlayerListener(null);
-        }
-        getPlayer().ifPresent(p -> p.removeFragmentListener(internalListener));
-    }
-
-    /**
-     * This listener will be held by the players created by {@link PlayerService}.
-     */
-    private final PlayerServiceEventListener internalListener =
-            new PlayerServiceEventListener() {
-                @Override
-                public void onViewCreated() {
-                    if (listener != null) {
-                        listener.onViewCreated();
-                    }
-                }
-
-                @Override
-                public void onFullscreenStateChanged(final boolean fullscreen) {
-                    if (listener != null) {
-                        listener.onFullscreenStateChanged(fullscreen);
-                    }
-                }
-
-                @Override
-                public void onScreenRotationButtonClicked() {
-                    if (listener != null) {
-                        listener.onScreenRotationButtonClicked();
-                    }
-                }
-
-                @Override
-                public void onMoreOptionsLongClicked() {
-                    if (listener != null) {
-                        listener.onMoreOptionsLongClicked();
-                    }
-                }
-
-                @Override
-                public void onPlayerError(final PlaybackException error,
-                                          final boolean isCatchableException) {
-                    if (listener != null) {
-                        listener.onPlayerError(error, isCatchableException);
-                    }
-                }
-
-                @Override
-                public void hideSystemUiIfNeeded() {
-                    if (listener != null) {
-                        listener.hideSystemUiIfNeeded();
-                    }
-                }
-
-                @Override
-                public void onQueueUpdate(final PlayQueue queue) {
-                    if (listener != null) {
-                        listener.onQueueUpdate(queue);
-                    }
-                }
-
-                @Override
-                public void onPlaybackUpdate(final int state,
-                                             final int repeatMode,
-                                             final boolean shuffled,
-                                             final PlaybackParameters parameters) {
-                    if (listener != null) {
-                        listener.onPlaybackUpdate(state, repeatMode, shuffled, parameters);
-                    }
-                }
-
-                @Override
-                public void onProgressUpdate(final int currentProgress,
-                                             final int duration,
-                                             final int bufferPercent) {
-                    if (listener != null) {
-                        listener.onProgressUpdate(currentProgress, duration, bufferPercent);
-                    }
-                }
-
-                @Override
-                public void onMetadataUpdate(final StreamInfo info, final PlayQueue queue) {
-                    if (listener != null) {
-                        listener.onMetadataUpdate(info, queue);
-                    }
-                }
-
-                @Override
-                public void onServiceStopped() {
-                    if (listener != null) {
-                        listener.onServiceStopped();
-                    }
-                    unbind(getCommonContext());
-                }
-            };
-
-    /**
-     * This listener will be held by bound {@link PlayerService}s to notify of the player starting
-     * or stopping. This is necessary since the service outlives the player e.g. to answer Android
-     * Auto media browser queries.
-     */
-    private final Consumer<Player> playerStateListener = (@Nullable final Player player) -> {
-        if (listener != null) {
-            if (player == null) {
-                // player.fragmentListener=null is already done by player.stopActivityBinding(),
-                // which is called by player.destroy(), which is in turn called by PlayerService
-                // before setting its player to null
-                listener.onPlayerDisconnected();
-            } else {
-                listener.onPlayerConnected(player, serviceConnection.playAfterConnect);
-                // reset the value of playAfterConnect: if it was true before, it is now "consumed"
-                serviceConnection.playAfterConnect = false;
-                player.setFragmentListener(internalListener);
-            }
-        }
-    };
-}

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

@@ -0,0 +1,316 @@
+package org.schabi.newpipe.player.helper
+
+import android.content.ComponentName
+import android.content.Context
+import android.content.Intent
+import android.content.ServiceConnection
+import android.os.IBinder
+import android.util.Log
+import androidx.core.content.ContextCompat
+import com.google.android.exoplayer2.PlaybackException
+import com.google.android.exoplayer2.PlaybackParameters
+import org.schabi.newpipe.App
+import org.schabi.newpipe.MainActivity
+import org.schabi.newpipe.extractor.stream.StreamInfo
+import org.schabi.newpipe.player.Player
+import org.schabi.newpipe.player.PlayerService
+import org.schabi.newpipe.player.PlayerService.LocalBinder
+import org.schabi.newpipe.player.PlayerType
+import org.schabi.newpipe.player.event.PlayerServiceEventListener
+import org.schabi.newpipe.player.event.PlayerServiceExtendedEventListener
+import org.schabi.newpipe.player.playqueue.PlayQueue
+import org.schabi.newpipe.util.NavigationHelper
+
+private val DEBUG = MainActivity.DEBUG
+private val TAG: String = PlayerHolder::class.java.getSimpleName()
+
+/**
+ * Singleton that manages a `PlayerService`
+ * and can be used to control the player instance through the service.
+ */
+object PlayerHolder {
+    private var listener: PlayerServiceExtendedEventListener? = null
+
+    var isBound: Boolean = false
+        private set
+
+    private var playerService: PlayerService? = null
+
+    private val player: Player?
+        get() = playerService?.player
+
+    // player play queue might be null e.g. while player is starting
+    private val playQueue: PlayQueue?
+        get() = this.player?.playQueue
+
+    val type: PlayerType?
+        /**
+         * Returns the current [PlayerType] of the [PlayerService] service,
+         * otherwise `null` if no service is running.
+         *
+         * @return Current PlayerType
+         */
+        get() = this.player?.playerType
+
+    val isPlaying: Boolean
+        get() = this.player?.isPlaying == true
+
+    val isPlayerOpen: Boolean
+        get() = this.player != null
+
+    val isPlayQueueReady: Boolean
+        /**
+         * Use this method to only allow the user to manipulate the play queue (e.g. by enqueueing via
+         * the stream long press menu) when there actually is a play queue to manipulate.
+         * @return true only if the player is open and its play queue is ready (i.e. it is not null)
+         */
+        get() = this.playQueue != null
+
+    val queueSize: Int
+        get() = this.playQueue?.size() ?: 0
+
+    val queuePosition: Int
+        get() = this.playQueue?.index ?: 0
+
+    fun setListener(newListener: PlayerServiceExtendedEventListener?) {
+        listener = newListener
+
+        // Force reload data from service
+        newListener?.let { listener ->
+            playerService?.let { service ->
+                listener.onServiceConnected(service)
+                startPlayerListener()
+                // ^ will call listener.onPlayerConnected() down the line if there is an active player
+            }
+        }
+    }
+
+    private val commonContext: Context
+        // helper to handle context in common place as using the same
+        get() = App.instance
+
+    /**
+     * Connect to (and if needed start) the [PlayerService]
+     * and bind [PlayerServiceConnection] to it.
+     * If the service is already started, only set the listener.
+     * @param playAfterConnect If this holder’s service was already started,
+     * start playing immediately
+     * @param newListener set this listener
+     */
+    fun startService(
+        playAfterConnect: Boolean,
+        newListener: PlayerServiceExtendedEventListener?
+    ) {
+        if (DEBUG) {
+            Log.d(TAG, "startService() called with playAfterConnect=$playAfterConnect")
+        }
+        val context = this.commonContext
+        setListener(newListener)
+        if (this.isBound) {
+            return
+        }
+        // startService() can be called concurrently and it will give a random crashes
+        // and NullPointerExceptions inside the service because the service will be
+        // bound twice. Prevent it with unbinding first
+        unbind(context)
+        val intent = Intent(context, PlayerService::class.java)
+        intent.putExtra(PlayerService.SHOULD_START_FOREGROUND_EXTRA, true)
+        ContextCompat.startForegroundService(context, intent)
+        PlayerServiceConnection.doPlayAfterConnect(playAfterConnect)
+        bind(context)
+    }
+
+    fun stopService() {
+        if (DEBUG) {
+            Log.d(TAG, "stopService() called")
+        }
+        playerService?.destroyPlayerAndStopService()
+        val context = this.commonContext
+        unbind(context)
+        // destroyPlayerAndStopService() already runs the next line of code, but run it again just
+        // to make sure to stop the service even if playerService is null by any chance.
+        context.stopService(Intent(context, PlayerService::class.java))
+    }
+
+    internal object PlayerServiceConnection : ServiceConnection {
+        internal var playAfterConnect = false
+
+        /**
+         * @param playAfterConnection Sets the value of [playAfterConnect] to pass to the
+         * [PlayerServiceExtendedEventListener.onPlayerConnected] the next time it
+         * is called. The value of [playAfterConnect] will be reset to false after that.
+         */
+        fun doPlayAfterConnect(playAfterConnection: Boolean) {
+            this.playAfterConnect = playAfterConnection
+        }
+
+        override fun onServiceDisconnected(compName: ComponentName?) {
+            if (DEBUG) {
+                Log.d(TAG, "Player service is disconnected")
+            }
+
+            val context: Context = this@PlayerHolder.commonContext
+            unbind(context)
+        }
+
+        override fun onServiceConnected(compName: ComponentName?, service: IBinder?) {
+            if (DEBUG) {
+                Log.d(TAG, "Player service is connected")
+            }
+            val localBinder = service as LocalBinder
+
+            val s = localBinder.service
+            requireNotNull(s) {
+                "PlayerService.LocalBinder.getService() must never be" +
+                    "null after the service connects"
+            }
+            playerService = s
+            listener?.let { l ->
+                l.onServiceConnected(s)
+                player?.let { l.onPlayerConnected(it, playAfterConnect) }
+            }
+            startPlayerListener()
+            // ^ will call listener.onPlayerConnected() down the line if there is an active player
+
+            // notify the main activity that binding the service has completed, so that it can
+            // open the bottom mini-player
+            NavigationHelper.sendPlayerStartedEvent(s)
+        }
+    }
+
+    private fun bind(context: Context) {
+        if (DEBUG) {
+            Log.d(TAG, "bind() called")
+        }
+        // BIND_AUTO_CREATE starts the service if it's not already running
+        this.isBound = bind(context, Context.BIND_AUTO_CREATE)
+        if (!this.isBound) {
+            context.unbindService(PlayerServiceConnection)
+        }
+    }
+
+    fun tryBindIfNeeded(context: Context) {
+        if (!this.isBound) {
+            // flags=0 means the service will not be started if it does not already exist. In this
+            // case the return value is not useful, as a value of "true" does not really indicate
+            // that the service is going to be bound.
+            bind(context, 0)
+        }
+    }
+
+    private fun bind(context: Context, flags: Int): Boolean {
+        val serviceIntent = Intent(context, PlayerService::class.java)
+        serviceIntent.setAction(PlayerService.BIND_PLAYER_HOLDER_ACTION)
+        return context.bindService(serviceIntent, PlayerServiceConnection, flags)
+    }
+
+    private fun unbind(context: Context) {
+        if (DEBUG) {
+            Log.d(TAG, "unbind() called")
+        }
+
+        if (this.isBound) {
+            context.unbindService(PlayerServiceConnection)
+            this.isBound = false
+            stopPlayerListener()
+            playerService = null
+            listener?.onPlayerDisconnected()
+            listener?.onServiceDisconnected()
+        }
+    }
+
+    private fun startPlayerListener() {
+        // setting the player listener will take care of calling relevant callbacks if the
+        // player in the service is (not) already active, also see playerStateListener below
+        playerService?.setPlayerListener(playerStateListener)
+        this.player?.setFragmentListener(HolderPlayerServiceEventListener)
+    }
+
+    private fun stopPlayerListener() {
+        playerService?.setPlayerListener(null)
+        this.player?.removeFragmentListener(HolderPlayerServiceEventListener)
+    }
+
+    /**
+     * This listener will be held by the players created by [PlayerService].
+     */
+    private object HolderPlayerServiceEventListener : PlayerServiceEventListener {
+        override fun onViewCreated() {
+            listener?.onViewCreated()
+        }
+
+        override fun onFullscreenStateChanged(fullscreen: Boolean) {
+            listener?.onFullscreenStateChanged(fullscreen)
+        }
+
+        override fun onScreenRotationButtonClicked() {
+            listener?.onScreenRotationButtonClicked()
+        }
+
+        override fun onMoreOptionsLongClicked() {
+            listener?.onMoreOptionsLongClicked()
+        }
+
+        override fun onPlayerError(
+            error: PlaybackException?,
+            isCatchableException: Boolean
+        ) {
+            listener?.onPlayerError(error, isCatchableException)
+        }
+
+        override fun hideSystemUiIfNeeded() {
+            listener?.hideSystemUiIfNeeded()
+        }
+
+        override fun onQueueUpdate(queue: PlayQueue?) {
+            listener?.onQueueUpdate(queue)
+        }
+
+        override fun onPlaybackUpdate(
+            state: Int,
+            repeatMode: Int,
+            shuffled: Boolean,
+            parameters: PlaybackParameters?
+        ) {
+            listener?.onPlaybackUpdate(state, repeatMode, shuffled, parameters)
+        }
+
+        override fun onProgressUpdate(
+            currentProgress: Int,
+            duration: Int,
+            bufferPercent: Int
+        ) {
+            listener?.onProgressUpdate(currentProgress, duration, bufferPercent)
+        }
+
+        override fun onMetadataUpdate(info: StreamInfo?, queue: PlayQueue?) {
+            listener?.onMetadataUpdate(info, queue)
+        }
+
+        override fun onServiceStopped() {
+            listener?.onServiceStopped()
+            unbind(this@PlayerHolder.commonContext)
+        }
+    }
+
+    /**
+     * This listener will be held by bound [PlayerService]s to notify of the player starting
+     * or stopping. This is necessary since the service outlives the player e.g. to answer Android
+     * Auto media browser queries.
+     */
+    private val playerStateListener: (Player?) -> Unit = { player: Player? ->
+        listener?.let { l ->
+            if (player == null) {
+                // player.fragmentListener=null is already done by player.stopActivityBinding(),
+                // which is called by player.destroy(), which is in turn called by PlayerService
+                // before setting its player to null
+                l.onPlayerDisconnected()
+            } else {
+                l.onPlayerConnected(player, PlayerServiceConnection.playAfterConnect)
+                // reset the value of playAfterConnect: if it was true before, it is now "consumed"
+                PlayerServiceConnection.playAfterConnect = false
+                player.setFragmentListener(HolderPlayerServiceEventListener)
+            }
+        }
+    }
+}

app/src/main/java/org/schabi/newpipe/player/mediabrowser/MediaBrowserImpl.kt

@@ -9,6 +9,7 @@ import android.support.v4.media.MediaDescriptionCompat
 import android.util.Log
 import androidx.annotation.DrawableRes
 import androidx.core.net.toUri
+import androidx.core.os.bundleOf
 import androidx.media.MediaBrowserServiceCompat
 import androidx.media.MediaBrowserServiceCompat.Result
 import androidx.media.utils.MediaConstants
@@ -36,7 +37,6 @@ import org.schabi.newpipe.local.playlist.RemotePlaylistManager
 import org.schabi.newpipe.util.ExtractorHelper
 import org.schabi.newpipe.util.ServiceHelper
 import org.schabi.newpipe.util.image.ImageStrategy
-import java.util.function.Consumer
 
 /**
  * This class is used to cleanly separate the Service implementation (in
@@ -46,16 +46,14 @@ import java.util.function.Consumer
  */
 class MediaBrowserImpl(
     private val context: Context,
-    notifyChildrenChanged: Consumer<String>, // parentId
+    notifyChildrenChanged: (parentId: String) -> Unit,
 ) {
     private val database = NewPipeDatabase.getInstance(context)
     private var disposables = CompositeDisposable()
 
     init {
         // this will listen to changes in the bookmarks until this MediaBrowserImpl is dispose()d
-        disposables.add(
+        disposables.add(getMergedPlaylists().subscribe { notifyChildrenChanged(ID_BOOKMARKS) })
-            getMergedPlaylists().subscribe { notifyChildrenChanged.accept(ID_BOOKMARKS) }
-        )
     }
 
     //region Cleanup
@@ -183,17 +181,16 @@ class MediaBrowserImpl(
 
     private fun createPlaylistMediaItem(playlist: PlaylistLocalItem): MediaBrowserCompat.MediaItem {
         val builder = MediaDescriptionCompat.Builder()
-        builder
             .setMediaId(createMediaIdForInfoItem(playlist is PlaylistRemoteEntity, playlist.uid))
             .setTitle(playlist.orderingName)
             .setIconUri(imageUriOrNullIfDisabled(playlist.thumbnailUrl))
+            .setExtras(
+                bundleOf(
+                    MediaConstants.DESCRIPTION_EXTRAS_KEY_CONTENT_STYLE_GROUP_TITLE
+                        to context.resources.getString(R.string.tab_bookmarks)
+                )
+            )
 
-        val extras = Bundle()
-        extras.putString(
-            MediaConstants.DESCRIPTION_EXTRAS_KEY_CONTENT_STYLE_GROUP_TITLE,
-            context.resources.getString(R.string.tab_bookmarks),
-        )
-        builder.setExtras(extras)
         return MediaBrowserCompat.MediaItem(
             builder.build(),
             MediaBrowserCompat.MediaItem.FLAG_BROWSABLE,
@@ -202,8 +199,9 @@ class MediaBrowserImpl(
 
     private fun createInfoItemMediaItem(item: InfoItem): MediaBrowserCompat.MediaItem? {
         val builder = MediaDescriptionCompat.Builder()
-        builder.setMediaId(createMediaIdForInfoItem(item))
+            .setMediaId(createMediaIdForInfoItem(item))
             .setTitle(item.name)
+            .setIconUri(ImageStrategy.choosePreferredImage(item.thumbnails)?.toUri())
 
         when (item.infoType) {
             InfoType.STREAM -> builder.setSubtitle((item as StreamInfoItem).uploaderName)
@@ -212,10 +210,6 @@ class MediaBrowserImpl(
             else -> return null
         }
 
-        ImageStrategy.choosePreferredImage(item.thumbnails)?.let {
-            builder.setIconUri(imageUriOrNullIfDisabled(it))
-        }
-
         return MediaBrowserCompat.MediaItem(
             builder.build(),
             MediaBrowserCompat.MediaItem.FLAG_PLAYABLE
@@ -256,7 +250,7 @@ class MediaBrowserImpl(
         index: Int,
     ): MediaBrowserCompat.MediaItem {
         val builder = MediaDescriptionCompat.Builder()
-        builder.setMediaId(createMediaIdForPlaylistIndex(false, playlistId, index))
+            .setMediaId(createMediaIdForPlaylistIndex(false, playlistId, index))
             .setTitle(item.streamEntity.title)
             .setSubtitle(item.streamEntity.uploader)
             .setIconUri(imageUriOrNullIfDisabled(item.streamEntity.thumbnailUrl))
@@ -276,10 +270,7 @@ class MediaBrowserImpl(
         builder.setMediaId(createMediaIdForPlaylistIndex(true, playlistId, index))
             .setTitle(item.name)
             .setSubtitle(item.uploaderName)
-
+            .setIconUri(ImageStrategy.choosePreferredImage(item.thumbnails)?.toUri())
-        ImageStrategy.choosePreferredImage(item.thumbnails)?.let {
-            builder.setIconUri(imageUriOrNullIfDisabled(it))
-        }
 
         return MediaBrowserCompat.MediaItem(
             builder.build(),

app/src/main/java/org/schabi/newpipe/player/mediasession/MediaSessionPlayerUi.java

@@ -124,8 +124,10 @@ public class MediaSessionPlayerUi extends PlayerUi
         MediaButtonReceiver.handleIntent(mediaSession, intent);
     }
 
-    public Optional<MediaSessionCompat.Token> getSessionToken() {
+
-        return Optional.ofNullable(mediaSession).map(MediaSessionCompat::getSessionToken);
+    @NonNull
+    public MediaSessionCompat.Token getSessionToken() {
+        return mediaSession.getSessionToken();
     }
 
 
@@ -138,7 +140,10 @@ public class MediaSessionPlayerUi extends PlayerUi
             public void play() {
                 player.play();
                 // hide the player controls even if the play command came from the media session
-                player.UIs().getOpt(VideoPlayerUi.class).ifPresent(ui -> ui.hideControls(0, 0));
+                final VideoPlayerUi ui = player.UIs().get(VideoPlayerUi.class);
+                if (ui != null) {
+                    ui.hideControls(0, 0);
+                }
             }
 
             @Override

app/src/main/java/org/schabi/newpipe/player/notification/NotificationUtil.java

@@ -101,10 +101,10 @@ public final class NotificationUtil {
             final int[] compactSlots = initializeNotificationSlots();
             mediaStyle.setShowActionsInCompactView(compactSlots);
         }
-        player.UIs()
+        @Nullable final MediaSessionPlayerUi ui = player.UIs().get(MediaSessionPlayerUi.class);
-                .getOpt(MediaSessionPlayerUi.class)
+        if (ui != null) {
-                .flatMap(MediaSessionPlayerUi::getSessionToken)
+            mediaStyle.setMediaSession(ui.getSessionToken());
-                .ifPresent(mediaStyle::setMediaSession);
+        }
 
         // setup notification builder
         builder.setStyle(mediaStyle)

app/src/main/java/org/schabi/newpipe/player/ui/PlayerUiList.kt

@@ -1,25 +1,20 @@
 package org.schabi.newpipe.player.ui
 
 import org.schabi.newpipe.util.GuardedByMutex
-import java.util.Optional
+import kotlin.reflect.KClass
+import kotlin.reflect.safeCast
 
+/**
+ * Creates a [PlayerUiList] starting with the provided player uis. The provided player uis
+ * will not be prepared like those passed to [.addAndPrepare], because when
+ * the [PlayerUiList] constructor is called, the player is still not running and it
+ * wouldn't make sense to initialize uis then. Instead the player will initialize them by doing
+ * proper calls to [.call].
+ *
+ * @param initialPlayerUis the player uis this list should start with; the order will be kept
+ */
 class PlayerUiList(vararg initialPlayerUis: PlayerUi) {
-    private val playerUis = GuardedByMutex(mutableListOf<PlayerUi>())
+    private val playerUis = GuardedByMutex(mutableListOf(*initialPlayerUis))
-
-    /**
-     * Creates a [PlayerUiList] starting with the provided player uis. The provided player uis
-     * will not be prepared like those passed to [.addAndPrepare], because when
-     * the [PlayerUiList] constructor is called, the player is still not running and it
-     * wouldn't make sense to initialize uis then. Instead the player will initialize them by doing
-     * proper calls to [.call].
-     *
-     * @param initialPlayerUis the player uis this list should start with; the order will be kept
-     */
-    init {
-        playerUis.runWithLockSync {
-            lockData.addAll(listOf(*initialPlayerUis))
-        }
-    }
 
     /**
      * Adds the provided player ui to the list and calls on it the initialization functions that
@@ -83,30 +78,22 @@ class PlayerUiList(vararg initialPlayerUis: PlayerUi) {
      * @param T the class type parameter
      * @return the first player UI of the required type found in the list, or null
      </T> */
-    fun <T : PlayerUi> get(playerUiType: Class<T>): T? =
+    fun <T : PlayerUi> get(playerUiType: KClass<T>): T? =
         playerUis.runWithLockSync {
             for (ui in lockData) {
                 if (playerUiType.isInstance(ui)) {
-                    when (val r = playerUiType.cast(ui)) {
+                    // try all UIs before returning null
-                        // try all UIs before returning null
+                    playerUiType.safeCast(ui)?.let { return@runWithLockSync it }
-                        null -> continue
-                        else -> return@runWithLockSync r
-                    }
                 }
             }
             return@runWithLockSync null
         }
 
     /**
-     * @param playerUiType the class of the player UI to return;
+     * See [get] above
-     * the [Class.isInstance] method will be used, so even subclasses could be returned
+     */
-     * @param T the class type parameter
+    fun <T : PlayerUi> get(playerUiType: Class<T>): T? =
-     * @return the first player UI of the required type found in the list, or an empty
+        get(playerUiType.kotlin)
-     * [Optional] otherwise
-     </T> */
-    @Deprecated("use get", ReplaceWith("get(playerUiType)"))
-    fun <T : PlayerUi> getOpt(playerUiType: Class<T>): Optional<T> =
-        Optional.ofNullable(get(playerUiType))
 
     /**
      * Calls the provided consumer on all player UIs in the list, in order of addition.

app/src/main/java/org/schabi/newpipe/ui/components/items/stream/StreamMenu.kt

@@ -28,10 +28,9 @@ fun StreamMenu(
 ) {
     val context = LocalContext.current
     val streamViewModel = viewModel<StreamViewModel>()
-    val playerHolder = PlayerHolder.getInstance()
 
     DropdownMenu(expanded = expanded, onDismissRequest = onDismissRequest) {
-        if (playerHolder.isPlayQueueReady) {
+        if (PlayerHolder.isPlayQueueReady) {
             DropdownMenuItem(
                 text = { Text(text = stringResource(R.string.enqueue_stream)) },
                 onClick = {
@@ -42,7 +41,7 @@ fun StreamMenu(
                 }
             )
 
-            if (playerHolder.queuePosition < playerHolder.queueSize - 1) {
+            if (PlayerHolder.queuePosition < PlayerHolder.queueSize - 1) {
                 DropdownMenuItem(
                     text = { Text(text = stringResource(R.string.enqueue_next_stream)) },
                     onClick = {

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

@@ -200,7 +200,7 @@ public final class NavigationHelper {
     }
 
     public static void enqueueOnPlayer(final Context context, final PlayQueue queue) {
-        PlayerType playerType = PlayerHolder.getInstance().getType();
+        PlayerType playerType = PlayerHolder.INSTANCE.getType();
         if (playerType == null) {
             Log.e(TAG, "Enqueueing but no player is open; defaulting to background player");
             playerType = PlayerType.AUDIO;
@@ -211,7 +211,7 @@ public final class NavigationHelper {
 
     /* ENQUEUE NEXT */
     public static void enqueueNextOnPlayer(final Context context, final PlayQueue queue) {
-        PlayerType playerType = PlayerHolder.getInstance().getType();
+        PlayerType playerType = PlayerHolder.INSTANCE.getType();
         if (playerType == null) {
             Log.e(TAG, "Enqueueing next but no player is open; defaulting to background player");
             playerType = PlayerType.AUDIO;
@@ -421,13 +421,13 @@ public final class NavigationHelper {
                                                final boolean switchingPlayers) {
 
         final boolean autoPlay;
-        @Nullable final PlayerType playerType = PlayerHolder.getInstance().getType();
+        @Nullable final PlayerType playerType = PlayerHolder.INSTANCE.getType();
         if (playerType == null) {
             // no player open
             autoPlay = PlayerHelper.isAutoplayAllowedByUser(context);
         } else if (switchingPlayers) {
             // switching player to main player
-            autoPlay = PlayerHolder.getInstance().isPlaying(); // keep play/pause state
+            autoPlay = PlayerHolder.INSTANCE.isPlaying(); // keep play/pause state
         } else if (playerType == PlayerType.MAIN) {
             // opening new stream while already playing in main player
             autoPlay = PlayerHelper.isAutoplayAllowedByUser(context);