Initialize MediaSessionCompat as part of PlayerService

It is needed for the media browser service, so it must continue living
even if the player is closed.

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

@@ -276,7 +276,7 @@ public Player(@NonNull final PlayerService service) {
         // notification ui in the UIs list, since the notification depends on the media session in
         // PlayerUi#initPlayer(), and UIs.call() guarantees UI order is preserved.
         UIs = new PlayerUiList(
-                new MediaSessionPlayerUi(this),
+                new MediaSessionPlayerUi(this, service.getMediaSession()),
                 new NotificationPlayerUi(this)
         );
     }

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

@@ -27,6 +27,7 @@
 import android.os.Bundle;
 import android.os.IBinder;
 import android.support.v4.media.MediaBrowserCompat.MediaItem;
+import android.support.v4.media.session.MediaSessionCompat;
 import android.util.Log;
 
 import androidx.annotation.NonNull;
@@ -37,7 +38,6 @@
 import org.schabi.newpipe.player.mediasession.MediaSessionPlayerUi;
 import org.schabi.newpipe.util.ThemeHelper;
 
-import java.util.ArrayList;
 import java.util.List;
 
 /**
@@ -49,8 +49,9 @@ public final class PlayerService extends MediaBrowserServiceCompat {
 
     private Player player;
 
-    private final IBinder mBinder = new PlayerService.LocalBinder();
+    private final IBinder mBinder = new LocalBinder();
     private MediaBrowserConnector mediaBrowserConnector;
+    private MediaSessionCompat mediaSession;
 
 
     /*//////////////////////////////////////////////////////////////////////////
@@ -67,10 +68,17 @@ public void onCreate() {
         assureCorrectAppLanguage(this);
         ThemeHelper.setTheme(this);
 
-        player = new Player(this);
+        mediaSession = new MediaSessionCompat(this, TAG);
+        initializePlayer();
         mediaBrowserConnector = new MediaBrowserConnector(this);
     }
 
+    private void initializePlayer() {
+        if (player == null) {
+            player = new Player(this);
+        }
+    }
+
     @Override
     public int onStartCommand(final Intent intent, final int flags, final int startId) {
         if (DEBUG) {
@@ -85,6 +93,7 @@ public int onStartCommand(final Intent intent, final int flags, final int startI
             return START_NOT_STICKY;
         }
 
+        initializePlayer();
         player.handleIntent(intent);
         player.UIs().get(MediaSessionPlayerUi.class)
                 .ifPresent(ui -> ui.handleMediaButtonIntent(intent));
@@ -124,6 +133,10 @@ public void onDestroy() {
             Log.d(TAG, "destroy() called");
         }
         cleanup();
+        if (mediaSession != null) {
+            mediaSession.release();
+            mediaSession = null;
+        }
     }
 
     private void cleanup() {
@@ -151,6 +164,10 @@ public IBinder onBind(final Intent intent) {
         return mBinder;
     }
 
+    public MediaSessionCompat getMediaSession() {
+        return mediaSession;
+    }
+
     public class LocalBinder extends Binder {
 
         public PlayerService getService() {

app/src/main/java/org/schabi/newpipe/player/mediabrowser/MediaBrowserConnector.java

@@ -20,6 +20,7 @@ public class MediaBrowserConnector {
 
     public MediaBrowserConnector(@NonNull final PlayerService playerService) {
         this.playerService = playerService;
+        playerService.setSessionToken(playerService.getMediaSession().getSessionToken());
     }
 
     @NonNull

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

@@ -26,21 +26,21 @@
 public class MediaSessionPlayerUi extends PlayerUi {
     private static final String TAG = "MediaSessUi";
 
-    private MediaSessionCompat mediaSession;
+    private final @NonNull MediaSessionCompat mediaSession;
     private MediaSessionConnector sessionConnector;
 
-    public MediaSessionPlayerUi(@NonNull final Player player) {
+    public MediaSessionPlayerUi(@NonNull final Player player,
+                                @NonNull final MediaSessionCompat mediaSession) {
         super(player);
+        this.mediaSession = mediaSession;
     }
 
     @Override
     public void initPlayer() {
         super.initPlayer();
         destroyPlayer(); // release previously used resources
 
-        mediaSession = new MediaSessionCompat(context, TAG);
         mediaSession.setActive(true);
-        player.getService().setSessionToken(mediaSession.getSessionToken());
 
         sessionConnector = new MediaSessionConnector(mediaSession);
         sessionConnector.setQueueNavigator(new PlayQueueNavigator(mediaSession, player));
@@ -58,11 +58,7 @@ public void destroyPlayer() {
             sessionConnector.setQueueNavigator(null);
             sessionConnector = null;
         }
-        if (mediaSession != null) {
-            mediaSession.setActive(false);
-            mediaSession.release();
-            mediaSession = null;
-        }
+        mediaSession.setActive(false);
     }
 
     @Override
@@ -80,7 +76,7 @@ public void handleMediaButtonIntent(final Intent intent) {
     }
 
     public Optional<MediaSessionCompat.Token> getSessionToken() {
-        return Optional.ofNullable(mediaSession).map(MediaSessionCompat::getSessionToken);
+        return Optional.of(mediaSession.getSessionToken());
     }