-Refactored playback resolvers and other persistent player objects to instantiate once only during player creation to enforce non-nullity.

-Fixed background and popup player service staying in foreground when playback is paused or completed.
-Fixed player metadata not updating on new stream.
-Fixed player intent playback quality not applied.
-Fixed player auto-queue not applied after stream transition or swapping.

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

@@ -37,6 +37,7 @@ import android.widget.RemoteViews;
 import com.google.android.exoplayer2.PlaybackParameters;
 import com.google.android.exoplayer2.Player;
 import com.google.android.exoplayer2.source.MediaSource;
+import com.nostra13.universalimageloader.core.assist.FailReason;
 
 import org.schabi.newpipe.BuildConfig;
 import org.schabi.newpipe.R;
@@ -264,16 +265,16 @@ public final class BackgroundPlayer extends Service {
 
     protected class BasePlayerImpl extends BasePlayer {
 
-        @Nullable private AudioPlaybackResolver resolver;
+        @NonNull final private AudioPlaybackResolver resolver;
 
         BasePlayerImpl(Context context) {
             super(context);
+            this.resolver = new AudioPlaybackResolver(context, dataSource);
         }
 
         @Override
         public void initPlayer(boolean playOnReady) {
             super.initPlayer(playOnReady);
-            resolver = new AudioPlaybackResolver(context, dataSource);
         }
 
         @Override
@@ -286,30 +287,65 @@ public final class BackgroundPlayer extends Service {
             startForeground(NOTIFICATION_ID, notBuilder.build());
         }
 
-        @Override
+        /*//////////////////////////////////////////////////////////////////////////
-        public void initThumbnail(final String url) {
+        // Thumbnail Loading
+        //////////////////////////////////////////////////////////////////////////*/
+
+        private void setDummyRemoteViewThumbnail() {
             resetNotification();
-            if (notRemoteView != null) notRemoteView.setImageViewResource(R.id.notificationCover, R.drawable.dummy_thumbnail);
+            if (notRemoteView != null) {
-            if (bigNotRemoteView != null) bigNotRemoteView.setImageViewResource(R.id.notificationCover, R.drawable.dummy_thumbnail);
+                notRemoteView.setImageViewResource(R.id.notificationCover,
+                        R.drawable.dummy_thumbnail);
+            }
+            if (bigNotRemoteView != null) {
+                bigNotRemoteView.setImageViewResource(R.id.notificationCover,
+                        R.drawable.dummy_thumbnail);
+            }
             updateNotification(-1);
-            super.initThumbnail(url);
+        }
+
+        @Override
+        public void onLoadingStarted(String imageUri, View view) {
+            super.onLoadingStarted(imageUri, view);
+            setDummyRemoteViewThumbnail();
         }
 
         @Override
         public void onLoadingComplete(String imageUri, View view, Bitmap loadedImage) {
             super.onLoadingComplete(imageUri, view, loadedImage);
-
+            if (loadedImage == null) {
-            if (loadedImage != null) {
+                setDummyRemoteViewThumbnail();
-                // rebuild notification here since remote view does not release bitmaps, causing memory leaks
+                return;
-                resetNotification();
-
-                if (notRemoteView != null) notRemoteView.setImageViewBitmap(R.id.notificationCover, loadedImage);
-                if (bigNotRemoteView != null) bigNotRemoteView.setImageViewBitmap(R.id.notificationCover, loadedImage);
-
-                updateNotification(-1);
             }
+
+            // rebuild notification here since remote view does not release bitmaps,
+            // causing memory leaks
+            resetNotification();
+            if (notRemoteView != null) {
+                notRemoteView.setImageViewBitmap(R.id.notificationCover, loadedImage);
+            }
+            if (bigNotRemoteView != null) {
+                bigNotRemoteView.setImageViewBitmap(R.id.notificationCover, loadedImage);
+            }
+            updateNotification(-1);
         }
 
+        @Override
+        public void onLoadingFailed(String imageUri, View view, FailReason failReason) {
+            super.onLoadingFailed(imageUri, view, failReason);
+            setDummyRemoteViewThumbnail();
+        }
+
+        @Override
+        public void onLoadingCancelled(String imageUri, View view) {
+            super.onLoadingCancelled(imageUri, view);
+            setDummyRemoteViewThumbnail();
+        }
+
+        /*//////////////////////////////////////////////////////////////////////////
+        // States Implementation
+        //////////////////////////////////////////////////////////////////////////*/
+
         @Override
         public void onPrepared(boolean playWhenReady) {
             super.onPrepared(playWhenReady);
@@ -385,17 +421,15 @@ public final class BackgroundPlayer extends Service {
 
         protected void onMetadataChanged(@NonNull final MediaSourceTag tag) {
             super.onMetadataChanged(tag);
-            if (shouldUpdateOnProgress) {
+            resetNotification();
-                resetNotification();
+            updateNotification(-1);
-                updateNotification(-1);
+            updateMetadata();
-                updateMetadata();
-            }
         }
 
         @Override
         @Nullable
         public MediaSource sourceOf(final PlayQueueItem item, final StreamInfo info) {
-            return resolver == null ? null : resolver.resolve(info);
+            return resolver.resolve(info);
         }
 
         @Override
@@ -515,18 +549,40 @@ public final class BackgroundPlayer extends Service {
             updateNotification(-1);
         }
 
+        @Override
+        public void onBlocked() {
+            super.onBlocked();
+            startForeground(NOTIFICATION_ID, notBuilder.build());
+        }
+
+        @Override
+        public void onBuffering() {
+            super.onBuffering();
+            startForeground(NOTIFICATION_ID, notBuilder.build());
+        }
+
+        @Override
+        public void onPausedSeek() {
+            super.onPausedSeek();
+            startForeground(NOTIFICATION_ID, notBuilder.build());
+        }
+
         @Override
         public void onPlaying() {
             super.onPlaying();
             updateNotification(R.drawable.ic_pause_white);
+
             lockManager.acquireWifiAndCpu();
+            startForeground(NOTIFICATION_ID, notBuilder.build());
         }
 
         @Override
         public void onPaused() {
             super.onPaused();
             updateNotification(R.drawable.ic_play_arrow_white);
+
             lockManager.releaseWifiAndCpu();
+            stopForeground(false);
         }
 
         @Override
@@ -539,6 +595,7 @@ public final class BackgroundPlayer extends Service {
             updateNotification(R.drawable.ic_replay_white);
 
             lockManager.releaseWifiAndCpu();
+            stopForeground(false);
         }
     }
 }

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

@@ -68,6 +68,7 @@ import org.schabi.newpipe.player.playqueue.PlayQueue;
 import org.schabi.newpipe.player.playqueue.PlayQueueAdapter;
 import org.schabi.newpipe.player.playqueue.PlayQueueItem;
 import org.schabi.newpipe.player.resolver.MediaSourceTag;
+import org.schabi.newpipe.util.ImageDisplayConstants;
 import org.schabi.newpipe.util.SerializedCache;
 
 import java.io.IOException;
@@ -78,6 +79,7 @@ import io.reactivex.Observable;
 import io.reactivex.android.schedulers.AndroidSchedulers;
 import io.reactivex.disposables.CompositeDisposable;
 import io.reactivex.disposables.Disposable;
+import io.reactivex.disposables.SerialDisposable;
 
 import static com.google.android.exoplayer2.Player.DISCONTINUITY_REASON_INTERNAL;
 import static com.google.android.exoplayer2.Player.DISCONTINUITY_REASON_PERIOD_TRANSITION;
@@ -104,6 +106,14 @@ public abstract class BasePlayer implements
 
     @NonNull final protected HistoryRecordManager recordManager;
 
+    @NonNull final protected CustomTrackSelector trackSelector;
+    @NonNull final protected PlayerDataSource dataSource;
+
+    @NonNull final private LoadControl loadControl;
+    @NonNull final private RenderersFactory renderFactory;
+
+    @NonNull final private SerialDisposable progressUpdateReactor;
+    @NonNull final private CompositeDisposable databaseUpdateReactor;
     /*//////////////////////////////////////////////////////////////////////////
     // Intent
     //////////////////////////////////////////////////////////////////////////*/
@@ -142,9 +152,6 @@ public abstract class BasePlayer implements
     protected final static int PROGRESS_LOOP_INTERVAL_MILLIS = 500;
     protected final static int RECOVERY_SKIP_THRESHOLD_MILLIS = 3000; // 3 seconds
 
-    protected CustomTrackSelector trackSelector;
-    protected PlayerDataSource dataSource;
-
     protected SimpleExoPlayer simpleExoPlayer;
     protected AudioReactor audioReactor;
     protected MediaSessionManager mediaSessionManager;
@@ -152,9 +159,6 @@ public abstract class BasePlayer implements
     private boolean isPrepared = false;
     private boolean isSynchronizing = false;
 
-    protected Disposable progressUpdateReactor;
-    protected CompositeDisposable databaseUpdateReactor;
-
     //////////////////////////////////////////////////////////////////////////*/
 
     public BasePlayer(@NonNull final Context context) {
@@ -171,29 +175,32 @@ public abstract class BasePlayer implements
         context.registerReceiver(broadcastReceiver, intentFilter);
 
         this.recordManager = new HistoryRecordManager(context);
+
+        this.progressUpdateReactor = new SerialDisposable();
+        this.databaseUpdateReactor = new CompositeDisposable();
+
+        final String userAgent = Downloader.USER_AGENT;
+        final DefaultBandwidthMeter bandwidthMeter = new DefaultBandwidthMeter();
+        this.dataSource = new PlayerDataSource(context, userAgent, bandwidthMeter);
+
+        final TrackSelection.Factory trackSelectionFactory =
+                PlayerHelper.getQualitySelector(context, bandwidthMeter);
+        this.trackSelector = new CustomTrackSelector(trackSelectionFactory);
+
+        this.loadControl = new LoadController(context);
+        this.renderFactory = new DefaultRenderersFactory(context);
     }
 
     public void setup() {
-        if (simpleExoPlayer == null) initPlayer(/*playOnInit=*/true);
+        if (simpleExoPlayer == null) {
+            initPlayer(/*playOnInit=*/true);
+        }
         initListeners();
     }
 
     public void initPlayer(final boolean playOnReady) {
         if (DEBUG) Log.d(TAG, "initPlayer() called with: context = [" + context + "]");
 
-        if (databaseUpdateReactor != null) databaseUpdateReactor.dispose();
-        databaseUpdateReactor = new CompositeDisposable();
-
-        final String userAgent = Downloader.USER_AGENT;
-        final DefaultBandwidthMeter bandwidthMeter = new DefaultBandwidthMeter();
-        dataSource = new PlayerDataSource(context, userAgent, bandwidthMeter);
-
-        final TrackSelection.Factory trackSelectionFactory =
-                PlayerHelper.getQualitySelector(context, bandwidthMeter);
-        trackSelector = new CustomTrackSelector(trackSelectionFactory);
-
-        final LoadControl loadControl = new LoadController(context);
-        final RenderersFactory renderFactory = new DefaultRenderersFactory(context);
         simpleExoPlayer = ExoPlayerFactory.newSimpleInstance(renderFactory, trackSelector, loadControl);
         simpleExoPlayer.addListener(this);
         simpleExoPlayer.setPlayWhenReady(playOnReady);
@@ -287,7 +294,6 @@ public abstract class BasePlayer implements
 
         if (mediaSessionManager != null) mediaSessionManager.dispose();
 
-        trackSelector = null;
         mediaSessionManager = null;
         simpleExoPlayer = null;
     }
@@ -296,11 +302,12 @@ public abstract class BasePlayer implements
     // Thumbnail Loading
     //////////////////////////////////////////////////////////////////////////*/
 
-    public void initThumbnail(final String url) {
+    private void initThumbnail(final String url) {
         if (DEBUG) Log.d(TAG, "Thumbnail - initThumbnail() called");
         if (url == null || url.isEmpty()) return;
         ImageLoader.getInstance().resume();
-        ImageLoader.getInstance().loadImage(url, this);
+        ImageLoader.getInstance().loadImage(url, ImageDisplayConstants.DISPLAY_THUMBNAIL_OPTIONS,
+                this);
     }
 
     @Override
@@ -461,13 +468,11 @@ public abstract class BasePlayer implements
     public abstract void onUpdateProgress(int currentProgress, int duration, int bufferPercent);
 
     protected void startProgressLoop() {
-        if (progressUpdateReactor != null) progressUpdateReactor.dispose();
+        progressUpdateReactor.set(getProgressReactor());
-        progressUpdateReactor = getProgressReactor();
     }
 
     protected void stopProgressLoop() {
-        if (progressUpdateReactor != null) progressUpdateReactor.dispose();
+        progressUpdateReactor.set(null);
-        progressUpdateReactor = null;
     }
 
     public void triggerProgressUpdate() {
@@ -482,7 +487,8 @@ public abstract class BasePlayer implements
     private Disposable getProgressReactor() {
         return Observable.interval(PROGRESS_LOOP_INTERVAL_MILLIS, TimeUnit.MILLISECONDS)
                 .observeOn(AndroidSchedulers.mainThread())
-                .subscribe(ignored -> triggerProgressUpdate());
+                .subscribe(ignored -> triggerProgressUpdate(),
+                        error -> Log.e(TAG, "Progress update failure: ", error));
     }
 
     /*//////////////////////////////////////////////////////////////////////////
@@ -496,12 +502,16 @@ public abstract class BasePlayer implements
                 (manifest == null ? "no manifest" : "available manifest") + ", " +
                 "timeline size = [" + timeline.getWindowCount() + "], " +
                 "reason = [" + reason + "]");
+
+        maybeUpdateCurrentMetadata();
     }
 
     @Override
     public void onTracksChanged(TrackGroupArray trackGroups, TrackSelectionArray trackSelections) {
         if (DEBUG) Log.d(TAG, "ExoPlayer - onTracksChanged(), " +
                 "track group size = " + trackGroups.length);
+
+        maybeUpdateCurrentMetadata();
     }
 
     @Override
@@ -521,6 +531,8 @@ public abstract class BasePlayer implements
         } else if (isLoading && !isProgressLoopRunning()) {
             startProgressLoop();
         }
+
+        maybeUpdateCurrentMetadata();
     }
 
     @Override
@@ -665,24 +677,22 @@ public abstract class BasePlayer implements
         if (DEBUG) Log.d(TAG, "ExoPlayer - onPositionDiscontinuity() called with " +
                 "reason = [" + reason + "]");
 
-        maybeUpdateCurrentMetadata();
-
         // Refresh the playback if there is a transition to the next video
         final int newPeriodIndex = simpleExoPlayer.getCurrentPeriodIndex();
-
-        /* Discontinuity reasons!! Thank you ExoPlayer lords */
         switch (reason) {
             case DISCONTINUITY_REASON_PERIOD_TRANSITION:
                 if (newPeriodIndex == playQueue.getIndex()) {
                     registerView();
                 } else {
-                    playQueue.offsetIndex(+1);
+                    playQueue.setIndex(newPeriodIndex);
                 }
             case DISCONTINUITY_REASON_SEEK:
             case DISCONTINUITY_REASON_SEEK_ADJUSTMENT:
             case DISCONTINUITY_REASON_INTERNAL:
                 break;
         }
+
+        maybeUpdateCurrentMetadata();
     }
 
     @Override
@@ -794,14 +804,6 @@ public abstract class BasePlayer implements
 
         initThumbnail(info.getThumbnailUrl());
         registerView();
-
-        // when starting playback on the last item when not repeating, maybe auto queue
-        if (playQueue.getIndex() == playQueue.size() - 1 &&
-                getRepeatMode() == Player.REPEAT_MODE_OFF &&
-                PlayerHelper.isAutoQueueEnabled(context)) {
-            final PlayQueue autoQueue = PlayerHelper.autoQueueOf(info, playQueue.getStreams());
-            if (autoQueue != null) playQueue.append(autoQueue.getStreams());
-        }
     }
 
     @Override
@@ -960,7 +962,7 @@ public abstract class BasePlayer implements
     //////////////////////////////////////////////////////////////////////////*/
 
     private void registerView() {
-        if (databaseUpdateReactor == null || currentMetadata == null) return;
+        if (currentMetadata == null) return;
         final StreamInfo currentInfo = currentMetadata.getMetadata();
         databaseUpdateReactor.add(recordManager.onViewed(currentInfo).onErrorComplete()
                 .subscribe(
@@ -980,7 +982,7 @@ public abstract class BasePlayer implements
     }
 
     protected void savePlaybackState(final StreamInfo info, final long progress) {
-        if (info == null || databaseUpdateReactor == null) return;
+        if (info == null) return;
         final Disposable stateSaver = recordManager.saveStreamState(info, progress)
                 .observeOn(AndroidSchedulers.mainThread())
                 .onErrorComplete()
@@ -1012,12 +1014,23 @@ public abstract class BasePlayer implements
             return;
         }
 
-        if (metadata == null || currentMetadata == metadata) return;
+        if (metadata == null) return;
+        maybeAutoQueueNextStream(metadata);
 
+        if (currentMetadata == metadata) return;
         currentMetadata = metadata;
         onMetadataChanged(metadata);
     }
 
+    private void maybeAutoQueueNextStream(@NonNull final MediaSourceTag currentMetadata) {
+        if (playQueue == null || playQueue.getIndex() != playQueue.size() - 1 ||
+                getRepeatMode() != Player.REPEAT_MODE_OFF ||
+                !PlayerHelper.isAutoQueueEnabled(context)) return;
+        // auto queue when starting playback on the last item when not repeating
+        final PlayQueue autoQueue = PlayerHelper.autoQueueOf(currentMetadata.getMetadata(),
+                playQueue.getStreams());
+        if (autoQueue != null) playQueue.append(autoQueue.getStreams());
+    }
     /*//////////////////////////////////////////////////////////////////////////
     // Getters and Setters
     //////////////////////////////////////////////////////////////////////////*/
@@ -1135,7 +1148,7 @@ public abstract class BasePlayer implements
     }
 
     public boolean isProgressLoopRunning() {
-        return progressUpdateReactor != null && !progressUpdateReactor.isDisposed();
+        return progressUpdateReactor.get() != null;
     }
 
     public void setRecovery() {

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

@@ -127,7 +127,7 @@ public final class MainVideoPlayer extends AppCompatActivity
 
         hideSystemUi();
         setContentView(R.layout.activity_main_player);
-        playerImpl = new VideoPlayerImpl(this);
+        playerImpl = new  VideoPlayerImpl(this);
         playerImpl.setup(findViewById(android.R.id.content));
 
         if (savedInstanceState != null && savedInstanceState.get(KEY_SAVED_STATE) != null) {
@@ -498,11 +498,11 @@ public final class MainVideoPlayer extends AppCompatActivity
         // Playback Listener
         //////////////////////////////////////////////////////////////////////////*/
 
-        protected void onMetadataChanged(@Nullable final MediaSourceTag tag) {
+        protected void onMetadataChanged(@NonNull final MediaSourceTag tag) {
             super.onMetadataChanged(tag);
 
-            titleTextView.setText(getVideoTitle());
+            titleTextView.setText(tag.getMetadata().getName());
-            channelTextView.setText(getUploaderName());
+            channelTextView.setText(tag.getMetadata().getUploaderName());
         }
 
         @Override

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

@@ -56,6 +56,7 @@ import com.google.android.exoplayer2.Player;
 import com.google.android.exoplayer2.text.CaptionStyleCompat;
 import com.google.android.exoplayer2.ui.AspectRatioFrameLayout;
 import com.google.android.exoplayer2.ui.SubtitleView;
+import com.nostra13.universalimageloader.core.assist.FailReason;
 
 import org.schabi.newpipe.BuildConfig;
 import org.schabi.newpipe.R;
@@ -428,21 +429,6 @@ public final class PopupVideoPlayer extends Service {
             super.destroy();
         }
 
-        @Override
-        public void onLoadingComplete(String imageUri, View view, Bitmap loadedImage) {
-            super.onLoadingComplete(imageUri, view, loadedImage);
-            if (loadedImage != null) {
-                // rebuild notification here since remote view does not release bitmaps, causing memory leaks
-                notBuilder = createNotification();
-
-                if (notRemoteView != null) {
-                    notRemoteView.setImageViewBitmap(R.id.notificationCover, loadedImage);
-                }
-
-                updateNotification(-1);
-            }
-        }
-
         @Override
         public void onFullScreenButtonClicked() {
             super.onFullScreenButtonClicked();
@@ -527,6 +513,54 @@ public final class PopupVideoPlayer extends Service {
             };
         }
 
+        /*//////////////////////////////////////////////////////////////////////////
+        // Thumbnail Loading
+        //////////////////////////////////////////////////////////////////////////*/
+
+        private void setDummyRemoteViewThumbnail() {
+            resetNotification();
+            if (notRemoteView != null) {
+                notRemoteView.setImageViewResource(R.id.notificationCover,
+                        R.drawable.dummy_thumbnail);
+            }
+            updateNotification(-1);
+        }
+
+        @Override
+        public void onLoadingStarted(String imageUri, View view) {
+            super.onLoadingStarted(imageUri, view);
+            setDummyRemoteViewThumbnail();
+        }
+
+        @Override
+        public void onLoadingComplete(String imageUri, View view, Bitmap loadedImage) {
+            super.onLoadingComplete(imageUri, view, loadedImage);
+            if (loadedImage == null) {
+                setDummyRemoteViewThumbnail();
+                return;
+            }
+
+            // rebuild notification here since remote view does not release bitmaps,
+            // causing memory leaks
+            resetNotification();
+            if (notRemoteView != null) {
+                notRemoteView.setImageViewBitmap(R.id.notificationCover, loadedImage);
+            }
+            updateNotification(-1);
+        }
+
+        @Override
+        public void onLoadingFailed(String imageUri, View view, FailReason failReason) {
+            super.onLoadingFailed(imageUri, view, failReason);
+            setDummyRemoteViewThumbnail();
+        }
+
+        @Override
+        public void onLoadingCancelled(String imageUri, View view) {
+            super.onLoadingCancelled(imageUri, view);
+            setDummyRemoteViewThumbnail();
+        }
+
         /*//////////////////////////////////////////////////////////////////////////
         // Activity Event Listener
         //////////////////////////////////////////////////////////////////////////*/
@@ -578,8 +612,8 @@ public final class PopupVideoPlayer extends Service {
         public void onRepeatModeChanged(int i) {
             super.onRepeatModeChanged(i);
             setRepeatModeRemote(notRemoteView, i);
-            updateNotification(-1);
             updatePlayback();
+            updateNotification(-1);
         }
 
         @Override
@@ -592,7 +626,7 @@ public final class PopupVideoPlayer extends Service {
         // Playback Listener
         //////////////////////////////////////////////////////////////////////////*/
 
-        protected void onMetadataChanged(@Nullable final MediaSourceTag tag) {
+        protected void onMetadataChanged(@NonNull final MediaSourceTag tag) {
             super.onMetadataChanged(tag);
             updateMetadata();
         }
@@ -651,12 +685,14 @@ public final class PopupVideoPlayer extends Service {
         public void changeState(int state) {
             super.changeState(state);
             updatePlayback();
+            updateNotification(-1);
         }
 
         @Override
         public void onBlocked() {
             super.onBlocked();
             updateNotification(R.drawable.ic_play_arrow_white);
+            startForeground(NOTIFICATION_ID, notBuilder.build());
         }
 
         @Override
@@ -664,19 +700,21 @@ public final class PopupVideoPlayer extends Service {
             super.onPlaying();
             updateNotification(R.drawable.ic_pause_white);
             videoPlayPause.setBackgroundResource(R.drawable.ic_pause_white);
-            lockManager.acquireWifiAndCpu();
-
             hideControls(DEFAULT_CONTROLS_DURATION, DEFAULT_CONTROLS_HIDE_TIME);
 
             windowLayoutParams.flags = WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON
                     | WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE;
             windowManager.updateViewLayout(playerImpl.getRootView(), windowLayoutParams);
+
+            startForeground(NOTIFICATION_ID, notBuilder.build());
+            lockManager.acquireWifiAndCpu();
         }
 
         @Override
         public void onBuffering() {
             super.onBuffering();
             updateNotification(R.drawable.ic_play_arrow_white);
+            startForeground(NOTIFICATION_ID, notBuilder.build());
         }
 
         @Override
@@ -684,10 +722,13 @@ public final class PopupVideoPlayer extends Service {
             super.onPaused();
             updateNotification(R.drawable.ic_play_arrow_white);
             videoPlayPause.setBackgroundResource(R.drawable.ic_play_arrow_white);
+
             lockManager.releaseWifiAndCpu();
 
             windowLayoutParams.flags = WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE;
             windowManager.updateViewLayout(playerImpl.getRootView(), windowLayoutParams);
+
+            stopForeground(false);
         }
 
         @Override
@@ -695,6 +736,7 @@ public final class PopupVideoPlayer extends Service {
             super.onPausedSeek();
             videoPlayPause.setBackgroundResource(R.drawable.ic_pause_white);
             updateNotification(R.drawable.ic_play_arrow_white);
+            startForeground(NOTIFICATION_ID, notBuilder.build());
         }
 
         @Override
@@ -702,10 +744,13 @@ public final class PopupVideoPlayer extends Service {
             super.onCompleted();
             updateNotification(R.drawable.ic_replay_white);
             videoPlayPause.setBackgroundResource(R.drawable.ic_replay_white);
+
             lockManager.releaseWifiAndCpu();
 
             windowLayoutParams.flags = WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE;
             windowManager.updateViewLayout(playerImpl.getRootView(), windowLayoutParams);
+
+            stopForeground(false);
         }
 
         @Override
@@ -731,7 +776,7 @@ public final class PopupVideoPlayer extends Service {
 
         /*package-private*/ void enableVideoRenderer(final boolean enable) {
             final int videoRendererIndex = getRendererIndex(C.TRACK_TYPE_VIDEO);
-            if (trackSelector != null && videoRendererIndex != RENDERER_UNAVAILABLE) {
+            if (videoRendererIndex != RENDERER_UNAVAILABLE) {
                 trackSelector.setParameters(trackSelector.buildUponParameters()
                         .setRendererDisabled(videoRendererIndex, !enable));
             }

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

@@ -103,7 +103,7 @@ public abstract class VideoPlayer extends BasePlayer
 
     protected boolean wasPlaying = false;
 
-    @Nullable private VideoPlaybackResolver resolver;
+    @NonNull final private VideoPlaybackResolver resolver;
     /*//////////////////////////////////////////////////////////////////////////
     // Views
     //////////////////////////////////////////////////////////////////////////*/
@@ -154,6 +154,7 @@ public abstract class VideoPlayer extends BasePlayer
     public VideoPlayer(String debugTag, Context context) {
         super(context);
         this.TAG = debugTag;
+        this.resolver = new VideoPlaybackResolver(context, dataSource, getQualityResolver());
     }
 
     public void setup(View rootView) {
@@ -236,8 +237,6 @@ public abstract class VideoPlayer extends BasePlayer
             trackSelector.setParameters(trackSelector.buildUponParameters()
                     .setTunnelingAudioSessionId(C.generateAudioSessionIdV21(context)));
         }
-
-        resolver = new VideoPlaybackResolver(context, dataSource, getQualityResolver());
     }
 
     @Override
@@ -292,7 +291,7 @@ public abstract class VideoPlayer extends BasePlayer
                 0, Menu.NONE, R.string.caption_none);
         captionOffItem.setOnMenuItemClickListener(menuItem -> {
             final int textRendererIndex = getRendererIndex(C.TRACK_TYPE_TEXT);
-            if (trackSelector != null && textRendererIndex != RENDERER_UNAVAILABLE) {
+            if (textRendererIndex != RENDERER_UNAVAILABLE) {
                 trackSelector.setParameters(trackSelector.buildUponParameters()
                         .setRendererDisabled(textRendererIndex, true));
             }
@@ -306,7 +305,7 @@ public abstract class VideoPlayer extends BasePlayer
                     i + 1, Menu.NONE, captionLanguage);
             captionItem.setOnMenuItemClickListener(menuItem -> {
                 final int textRendererIndex = getRendererIndex(C.TRACK_TYPE_TEXT);
-                if (trackSelector != null && textRendererIndex != RENDERER_UNAVAILABLE) {
+                if (textRendererIndex != RENDERER_UNAVAILABLE) {
                     trackSelector.setPreferredTextLanguage(captionLanguage);
                     trackSelector.setParameters(trackSelector.buildUponParameters()
                             .setRendererDisabled(textRendererIndex, false));
@@ -369,7 +368,7 @@ public abstract class VideoPlayer extends BasePlayer
     @Override
     @Nullable
     public MediaSource sourceOf(final PlayQueueItem item, final StreamInfo info) {
-        return resolver == null ? null : resolver.resolve(info);
+        return resolver.resolve(info);
     }
 
     /*//////////////////////////////////////////////////////////////////////////
@@ -480,8 +479,7 @@ public abstract class VideoPlayer extends BasePlayer
         final int textRenderer = getRendererIndex(C.TRACK_TYPE_TEXT);
 
         if (captionTextView == null) return;
-        if (trackSelector == null || trackSelector.getCurrentMappedTrackInfo() == null ||
+        if (trackSelector.getCurrentMappedTrackInfo() == null || textRenderer == RENDERER_UNAVAILABLE) {
-                textRenderer == RENDERER_UNAVAILABLE) {
             captionTextView.setVisibility(View.GONE);
             return;
         }
@@ -833,12 +831,12 @@ public abstract class VideoPlayer extends BasePlayer
     //////////////////////////////////////////////////////////////////////////*/
 
     public void setPlaybackQuality(final String quality) {
-        if (resolver != null) resolver.setPlaybackQuality(quality);
+        this.resolver.setPlaybackQuality(quality);
     }
 
     @Nullable
     public String getPlaybackQuality() {
-        return resolver == null ? null : resolver.getPlaybackQuality();
+        return resolver.getPlaybackQuality();
     }
 
     public AspectRatioFrameLayout getAspectRatioFrameLayout() {

app/src/main/java/org/schabi/newpipe/player/resolver/AudioPlaybackResolver.java

@@ -2,6 +2,7 @@ package org.schabi.newpipe.player.resolver;
 
 import android.content.Context;
 import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
 
 import com.google.android.exoplayer2.source.MediaSource;
 
@@ -24,6 +25,7 @@ public class AudioPlaybackResolver implements PlaybackResolver {
     }
 
     @Override
+    @Nullable
     public MediaSource resolve(@NonNull StreamInfo info) {
         final MediaSource liveSource = maybeBuildLiveMediaSource(dataSource, info);
         if (liveSource != null) return liveSource;

app/src/main/java/org/schabi/newpipe/player/resolver/Resolver.java

@@ -1,7 +1,8 @@
 package org.schabi.newpipe.player.resolver;
 
 import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
 
 public interface Resolver<Source, Product> {
-    Product resolve(@NonNull Source source);
+    @Nullable Product resolve(@NonNull Source source);
 }

app/src/main/java/org/schabi/newpipe/player/resolver/VideoPlaybackResolver.java

@@ -47,6 +47,7 @@ public class VideoPlaybackResolver implements PlaybackResolver {
     }
 
     @Override
+    @Nullable
     public MediaSource resolve(@NonNull StreamInfo info) {
         final MediaSource liveSource = maybeBuildLiveMediaSource(dataSource, info);
         if (liveSource != null) return liveSource;