-Added new intents to append streams to current player.

-Added long clicks for popup and background player buttons on details fragment for append intents.
-Removed restrictions for preventing UI to show up when player is buffering.
-Fixed icons for all repeat modes.
-Added Progress bar to background activity when player is in not ready state.
-Fixed Track Selection when switching between video and audio only on video players.
-Fixed video player to enable tunnelling only after sdk > 21.
-Fixed activity exception from restarting after service is shutdown on earlier sdk versions.

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

@@ -92,7 +92,7 @@ import io.reactivex.schedulers.Schedulers;
 
 import static org.schabi.newpipe.util.AnimationUtils.animateView;
 
-public class VideoDetailFragment extends BaseStateFragment<StreamInfo> implements BackPressable, SharedPreferences.OnSharedPreferenceChangeListener, View.OnClickListener {
+public class VideoDetailFragment extends BaseStateFragment<StreamInfo> implements BackPressable, SharedPreferences.OnSharedPreferenceChangeListener, View.OnClickListener, View.OnLongClickListener {
     public static final String AUTO_PLAY = "auto_play";
 
     // Amount of videos to show on start
@@ -320,10 +320,10 @@ public class VideoDetailFragment extends BaseStateFragment<StreamInfo> implement
 
         switch (v.getId()) {
             case R.id.detail_controls_background:
-                openBackgroundPlayer();
+                openBackgroundPlayer(false);
                 break;
             case R.id.detail_controls_popup:
-                openPopupPlayer();
+                openPopupPlayer(false);
                 break;
             case R.id.detail_uploader_root_layout:
                 if (currentInfo.uploader_url == null || currentInfo.uploader_url.isEmpty()) {
@@ -344,6 +344,22 @@ public class VideoDetailFragment extends BaseStateFragment<StreamInfo> implement
         }
     }
 
+    @Override
+    public boolean onLongClick(View v) {
+        if (isLoading.get() || currentInfo == null) return false;
+
+        switch (v.getId()) {
+            case R.id.detail_controls_background:
+                openBackgroundPlayer(true);
+                break;
+            case R.id.detail_controls_popup:
+                openPopupPlayer(true);
+                break;
+        }
+
+        return true;
+    }
+
     private void toggleTitleAndDescription() {
         if (videoDescriptionRootLayout.getVisibility() == View.VISIBLE) {
             videoTitleTextView.setMaxLines(1);
@@ -448,6 +464,11 @@ public class VideoDetailFragment extends BaseStateFragment<StreamInfo> implement
         detailControlsBackground.setOnClickListener(this);
         detailControlsPopup.setOnClickListener(this);
         relatedStreamExpandButton.setOnClickListener(this);
+
+        detailControlsBackground.setLongClickable(true);
+        detailControlsPopup.setLongClickable(true);
+        detailControlsBackground.setOnLongClickListener(this);
+        detailControlsPopup.setOnLongClickListener(this);
     }
 
     private void initThumbnailViews(StreamInfo info) {
@@ -716,7 +737,7 @@ public class VideoDetailFragment extends BaseStateFragment<StreamInfo> implement
     // Play Utils
     //////////////////////////////////////////////////////////////////////////*/
 
-    private void openBackgroundPlayer() {
+    private void openBackgroundPlayer(final boolean append) {
         AudioStream audioStream = currentInfo.audio_streams.get(ListHelper.getDefaultAudioFormat(activity, currentInfo.audio_streams));
 
         if (activity instanceof HistoryListener) {
@@ -727,7 +748,7 @@ public class VideoDetailFragment extends BaseStateFragment<StreamInfo> implement
                 .getBoolean(activity.getString(R.string.use_external_audio_player_key), false);
 
         if (!useExternalAudioPlayer && android.os.Build.VERSION.SDK_INT >= 16) {
-            openNormalBackgroundPlayer();
+            openNormalBackgroundPlayer(append);
         } else {
             openExternalBackgroundPlayer(audioStream);
         }
@@ -742,7 +763,7 @@ public class VideoDetailFragment extends BaseStateFragment<StreamInfo> implement
         }
     }
 
-    private void openPopupPlayer() {
+    private void openPopupPlayer(final boolean append) {
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M && !PermissionHelper.checkSystemAlertWindowPermission(activity)) {
             Toast toast = Toast.makeText(activity, R.string.msg_popup_permission, Toast.LENGTH_LONG);
             TextView messageView = toast.getView().findViewById(android.R.id.message);
@@ -759,7 +780,13 @@ public class VideoDetailFragment extends BaseStateFragment<StreamInfo> implement
 
         final PlayQueue playQueue = new SinglePlayQueue(currentInfo);
         final VideoStream candidate = sortedStreamVideosList.get(actionBarHandler.getSelectedVideoStream());
-        final Intent intent = NavigationHelper.getPlayerIntent(activity, PopupVideoPlayer.class, playQueue, resolutionOf(candidate.resolution));
+
+        final Intent intent;
+        if (append) {
+            intent = NavigationHelper.getPlayerIntent(activity, PopupVideoPlayer.class, playQueue, true);
+        } else {
+            intent = NavigationHelper.getPlayerIntent(activity, PopupVideoPlayer.class, playQueue, resolutionOf(candidate.resolution));
+        }
         activity.startService(intent);
     }
 
@@ -778,9 +805,9 @@ public class VideoDetailFragment extends BaseStateFragment<StreamInfo> implement
     }
 
 
-    private void openNormalBackgroundPlayer() {
+    private void openNormalBackgroundPlayer(final boolean append) {
         final PlayQueue playQueue = new SinglePlayQueue(currentInfo);
-        activity.startService(NavigationHelper.getPlayerIntent(activity, BackgroundPlayer.class, playQueue));
+        activity.startService(NavigationHelper.getPlayerIntent(activity, BackgroundPlayer.class, playQueue, append));
         Toast.makeText(activity, R.string.background_player_playing_toast, Toast.LENGTH_SHORT).show();
     }
 

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

@@ -44,14 +44,11 @@ import com.google.android.exoplayer2.Player;
 import com.google.android.exoplayer2.source.MediaSource;
 
 import org.schabi.newpipe.BuildConfig;
-import org.schabi.newpipe.MainActivity;
 import org.schabi.newpipe.R;
 import org.schabi.newpipe.extractor.MediaFormat;
-import org.schabi.newpipe.extractor.StreamingService;
 import org.schabi.newpipe.extractor.stream.AudioStream;
 import org.schabi.newpipe.extractor.stream.StreamInfo;
 import org.schabi.newpipe.playlist.PlayQueueItem;
-import org.schabi.newpipe.util.Constants;
 import org.schabi.newpipe.util.ListHelper;
 import org.schabi.newpipe.util.ThemeHelper;
 
@@ -108,6 +105,7 @@ public final class BackgroundPlayer extends Service {
     private RemoteViews notRemoteView;
     private RemoteViews bigNotRemoteView;
     private final String setAlphaMethodName = (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) ? "setImageAlpha" : "setAlpha";
+    private final String setImageResourceMethodName = "setImageResource";
 
     /*//////////////////////////////////////////////////////////////////////////
     // Service's LifeCycle
@@ -137,12 +135,7 @@ public final class BackgroundPlayer extends Service {
     @Override
     public void onDestroy() {
         if (DEBUG) Log.d(TAG, "destroy() called");
-        releaseWifiAndCpu();
+        onClose();
-        stopForeground(true);
-
-        if (basePlayerImpl != null) basePlayerImpl.destroy();
-        basePlayerImpl = null;
-        mBinder = null;
     }
 
     @Override
@@ -156,18 +149,22 @@ public final class BackgroundPlayer extends Service {
 
     public void openControl(final Context context) {
         final Intent intent = new Intent(context, BackgroundPlayerActivity.class);
+        intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
         context.startActivity(intent);
         context.sendBroadcast(new Intent(Intent.ACTION_CLOSE_SYSTEM_DIALOGS));
     }
 
     private void onClose() {
-        if (basePlayerImpl != null) {
-            basePlayerImpl.stopActivityBinding();
-            basePlayerImpl.destroyPlayer();
-        }
-
         stopForeground(true);
         releaseWifiAndCpu();
+
+        if (basePlayerImpl != null) {
+            basePlayerImpl.stopActivityBinding();
+            basePlayerImpl.destroy();
+        }
+
+        basePlayerImpl = null;
+        mBinder = null;
         stopSelf();
     }
 
@@ -222,18 +219,7 @@ public final class BackgroundPlayer extends Service {
         remoteViews.setOnClickPendingIntent(R.id.notificationFForward,
                 PendingIntent.getBroadcast(this, NOTIFICATION_ID, new Intent(ACTION_FAST_FORWARD), PendingIntent.FLAG_UPDATE_CURRENT));
 
-        switch (basePlayerImpl.simpleExoPlayer.getRepeatMode()) {
+        setRepeatModeIcon(remoteViews, basePlayerImpl.simpleExoPlayer.getRepeatMode());
-            case Player.REPEAT_MODE_OFF:
-                remoteViews.setInt(R.id.notificationRepeat, setAlphaMethodName, 77);
-                break;
-            case Player.REPEAT_MODE_ONE:
-                // todo change image
-                remoteViews.setInt(R.id.notificationRepeat, setAlphaMethodName, 168);
-                break;
-            case Player.REPEAT_MODE_ALL:
-                remoteViews.setInt(R.id.notificationRepeat, setAlphaMethodName, 255);
-                break;
-        }
     }
 
     /**
@@ -285,6 +271,19 @@ public final class BackgroundPlayer extends Service {
         wifiLock = null;
     }
 
+    private void setRepeatModeIcon(final RemoteViews remoteViews, final int repeatMode) {
+        switch (repeatMode) {
+            case Player.REPEAT_MODE_OFF:
+                remoteViews.setInt(R.id.notificationRepeat, setImageResourceMethodName, R.drawable.exo_controls_repeat_off);
+                break;
+            case Player.REPEAT_MODE_ONE:
+                remoteViews.setInt(R.id.notificationRepeat, setImageResourceMethodName, R.drawable.exo_controls_repeat_one);
+                break;
+            case Player.REPEAT_MODE_ALL:
+                remoteViews.setInt(R.id.notificationRepeat, setImageResourceMethodName, R.drawable.exo_controls_repeat_all);
+                break;
+        }
+    }
     //////////////////////////////////////////////////////////////////////////
 
     protected class BasePlayerImpl extends BasePlayer {
@@ -424,21 +423,8 @@ public final class BackgroundPlayer extends Service {
 
         @Override
         public void onRepeatModeChanged(int i) {
-            int opacity = 255;
+            setRepeatModeIcon(notRemoteView, i);
-            switch (simpleExoPlayer.getRepeatMode()) {
+            setRepeatModeIcon(bigNotRemoteView, i);
-                case Player.REPEAT_MODE_OFF:
-                    opacity = 77;
-                    break;
-                case Player.REPEAT_MODE_ONE:
-                    // todo change image
-                    opacity = 168;
-                    break;
-                case Player.REPEAT_MODE_ALL:
-                    opacity = 255;
-                    break;
-            }
-            if (notRemoteView != null) notRemoteView.setInt(R.id.notificationRepeat, setAlphaMethodName, opacity);
-            if (bigNotRemoteView != null) bigNotRemoteView.setInt(R.id.notificationRepeat, setAlphaMethodName, opacity);
             updateNotification(-1);
             updatePlayback();
         }

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

@@ -18,6 +18,7 @@ import android.view.MenuItem;
 import android.view.View;
 import android.widget.ImageButton;
 import android.widget.PopupMenu;
+import android.widget.ProgressBar;
 import android.widget.SeekBar;
 import android.widget.TextView;
 
@@ -70,6 +71,7 @@ public class BackgroundPlayerActivity extends AppCompatActivity
     private ImageButton playPauseButton;
     private ImageButton forwardButton;
     private ImageButton shuffleButton;
+    private ProgressBar progressBar;
 
     private TextView playbackSpeedButton;
     private PopupMenu playbackSpeedPopupMenu;
@@ -164,7 +166,7 @@ public class BackgroundPlayerActivity extends AppCompatActivity
                 Log.d(TAG, "Background player service is connected");
                 final BackgroundPlayer.LocalBinder mLocalBinder = (BackgroundPlayer.LocalBinder) service;
                 player = mLocalBinder.getBackgroundPlayerInstance();
-                if (player == null) {
+                if (player == null || player.playQueue == null || player.playQueueAdapter == null || player.simpleExoPlayer == null) {
                     unbind();
                 } else {
                     buildComponents();
@@ -219,6 +221,7 @@ public class BackgroundPlayerActivity extends AppCompatActivity
         shuffleButton = rootView.findViewById(R.id.control_shuffle);
         playbackSpeedButton = rootView.findViewById(R.id.control_playback_speed);
         playbackPitchButton = rootView.findViewById(R.id.control_playback_pitch);
+        progressBar = rootView.findViewById(R.id.control_progress_bar);
 
         repeatButton.setOnClickListener(this);
         backwardButton.setOnClickListener(this);
@@ -431,52 +434,9 @@ public class BackgroundPlayerActivity extends AppCompatActivity
 
     @Override
     public void onPlaybackUpdate(int state, int repeatMode, boolean shuffled, PlaybackParameters parameters) {
-        switch (state) {
+        onStateChanged(state);
-            case BasePlayer.STATE_PAUSED:
+        onPlayModeChanged(repeatMode, shuffled);
-                playPauseButton.setImageResource(R.drawable.ic_play_arrow_white);
+        onPlaybackParameterChanged(parameters);
-                break;
-            case BasePlayer.STATE_PLAYING:
-                playPauseButton.setImageResource(R.drawable.ic_pause_white);
-                break;
-            case BasePlayer.STATE_COMPLETED:
-                playPauseButton.setImageResource(R.drawable.ic_replay_white);
-                break;
-            default:
-                break;
-        }
-
-        int repeatAlpha = 255;
-        switch (repeatMode) {
-            case Player.REPEAT_MODE_OFF:
-                repeatAlpha = 77;
-                break;
-            case Player.REPEAT_MODE_ONE:
-                // todo change image
-                repeatAlpha = 168;
-                break;
-            case Player.REPEAT_MODE_ALL:
-                repeatAlpha = 255;
-                break;
-        }
-
-        int shuffleAlpha = 255;
-        if (!shuffled) {
-            shuffleAlpha = 77;
-        }
-
-        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
-            repeatButton.setImageAlpha(repeatAlpha);
-            shuffleButton.setImageAlpha(shuffleAlpha);
-        } else {
-            repeatButton.setAlpha(repeatAlpha);
-            shuffleButton.setAlpha(shuffleAlpha);
-        }
-
-        if (parameters != null) {
-            playbackSpeedButton.setText(player.formatSpeed(parameters.speed));
-            playbackPitchButton.setText(player.formatPitch(parameters.pitch));
-        }
-
         scrollToSelected();
     }
 
@@ -509,4 +469,67 @@ public class BackgroundPlayerActivity extends AppCompatActivity
     public void onServiceStopped() {
         unbind();
     }
+
+    ////////////////////////////////////////////////////////////////////////////
+    // Binding Service Helper
+    ////////////////////////////////////////////////////////////////////////////
+
+    private void onStateChanged(final int state) {
+        switch (state) {
+            case BasePlayer.STATE_PAUSED:
+                playPauseButton.setImageResource(R.drawable.ic_play_arrow_white);
+                break;
+            case BasePlayer.STATE_PLAYING:
+                playPauseButton.setImageResource(R.drawable.ic_pause_white);
+                break;
+            case BasePlayer.STATE_COMPLETED:
+                playPauseButton.setImageResource(R.drawable.ic_replay_white);
+                break;
+            default:
+                break;
+        }
+
+        switch (state) {
+            case BasePlayer.STATE_PAUSED:
+            case BasePlayer.STATE_PLAYING:
+            case BasePlayer.STATE_COMPLETED:
+                playPauseButton.setClickable(true);
+                playPauseButton.setVisibility(View.VISIBLE);
+                progressBar.setVisibility(View.GONE);
+                break;
+            default:
+                playPauseButton.setClickable(false);
+                playPauseButton.setVisibility(View.INVISIBLE);
+                progressBar.setVisibility(View.VISIBLE);
+                break;
+        }
+    }
+
+    private void onPlayModeChanged(final int repeatMode, final boolean shuffled) {
+        switch (repeatMode) {
+            case Player.REPEAT_MODE_OFF:
+                repeatButton.setImageResource(R.drawable.exo_controls_repeat_off);
+                break;
+            case Player.REPEAT_MODE_ONE:
+                repeatButton.setImageResource(R.drawable.exo_controls_repeat_one);
+                break;
+            case Player.REPEAT_MODE_ALL:
+                repeatButton.setImageResource(R.drawable.exo_controls_repeat_all);
+                break;
+        }
+
+        final int shuffleAlpha = shuffled ? 255 : 77;
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
+            shuffleButton.setImageAlpha(shuffleAlpha);
+        } else {
+            shuffleButton.setAlpha(shuffleAlpha);
+        }
+    }
+
+    private void onPlaybackParameterChanged(final PlaybackParameters parameters) {
+        if (parameters != null) {
+            playbackSpeedButton.setText(player.formatSpeed(parameters.speed));
+            playbackPitchButton.setText(player.formatPitch(parameters.pitch));
+        }
+    }
 }

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

@@ -137,6 +137,7 @@ public abstract class BasePlayer implements Player.EventListener,
     public static final String PLAY_QUEUE = "play_queue";
     public static final String RESTORE_QUEUE_INDEX = "restore_queue_index";
     public static final String RESTORE_WINDOW_POS = "restore_window_pos";
+    public static final String APPEND_ONLY = "append_only";
 
     /*//////////////////////////////////////////////////////////////////////////
     // Playback
@@ -260,6 +261,12 @@ public abstract class BasePlayer implements Player.EventListener,
         if (!(playQueueCandidate instanceof PlayQueue)) return;
         final PlayQueue queue = (PlayQueue) playQueueCandidate;
 
+        // Resolve append intents
+        if (intent.getBooleanExtra(APPEND_ONLY, false) && playQueue != null) {
+            playQueue.append(queue.getStreams());
+            return;
+        }
+
         // Resolve playback details
         if (intent.hasExtra(RESTORE_QUEUE_INDEX) && intent.hasExtra(START_POSITION)) {
             setRecovery(
@@ -310,6 +317,7 @@ public abstract class BasePlayer implements Player.EventListener,
     public void destroyPlayer() {
         if (DEBUG) Log.d(TAG, "destroyPlayer() called");
         if (simpleExoPlayer != null) {
+            simpleExoPlayer.removeListener(this);
             simpleExoPlayer.stop();
             simpleExoPlayer.release();
         }

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

@@ -189,6 +189,20 @@ public final class MainVideoPlayer extends Activity {
                 : ActivityInfo.SCREEN_ORIENTATION_SENSOR_PORTRAIT);
     }
 
+    protected void setRepeatModeButton(final ImageButton imageButton, final int repeatMode) {
+        switch (repeatMode) {
+            case Player.REPEAT_MODE_OFF:
+                imageButton.setImageResource(R.drawable.exo_controls_repeat_off);
+                break;
+            case Player.REPEAT_MODE_ONE:
+                imageButton.setImageResource(R.drawable.exo_controls_repeat_one);
+                break;
+            case Player.REPEAT_MODE_ALL:
+                imageButton.setImageResource(R.drawable.exo_controls_repeat_all);
+                break;
+        }
+    }
+
     ///////////////////////////////////////////////////////////////////////////
 
     @SuppressWarnings({"unused", "WeakerAccess"})
@@ -218,12 +232,6 @@ public final class MainVideoPlayer extends Activity {
             this.screenRotationButton = rootView.findViewById(R.id.screenRotationButton);
             this.playPauseButton = rootView.findViewById(R.id.playPauseButton);
 
-            // Due to a bug on lower API, lets set the alpha instead of using a drawable
-            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) repeatButton.setImageAlpha(77);
-            else { //noinspection deprecation
-                repeatButton.setAlpha(77);
-            }
-
             getRootView().setKeepScreenOn(true);
         }
 
@@ -241,6 +249,16 @@ public final class MainVideoPlayer extends Activity {
             screenRotationButton.setOnClickListener(this);
         }
 
+        /*//////////////////////////////////////////////////////////////////////////
+        // ExoPlayer Video Listener
+        //////////////////////////////////////////////////////////////////////////*/
+
+        @Override
+        public void onRepeatModeChanged(int i) {
+            super.onRepeatModeChanged(i);
+            setRepeatModeButton(repeatButton, simpleExoPlayer.getRepeatMode());
+        }
+
         /*//////////////////////////////////////////////////////////////////////////
         // Playback Listener
         //////////////////////////////////////////////////////////////////////////*/
@@ -289,31 +307,6 @@ public final class MainVideoPlayer extends Activity {
             finish();
         }
 
-        @Override
-        @SuppressWarnings("deprecation")
-        public void onRepeatClicked() {
-            super.onRepeatClicked();
-            if (DEBUG) Log.d(TAG, "onRepeatClicked() called");
-            switch (simpleExoPlayer.getRepeatMode()) {
-                case Player.REPEAT_MODE_OFF:
-                    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) repeatButton.setImageAlpha(77);
-                    else repeatButton.setAlpha(77);
-
-                    break;
-                case Player.REPEAT_MODE_ONE:
-                    // todo change image
-                    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) repeatButton.setImageAlpha(168);
-                    else repeatButton.setAlpha(168);
-
-                    break;
-                case Player.REPEAT_MODE_ALL:
-                    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) repeatButton.setImageAlpha(255);
-                    else repeatButton.setAlpha(255);
-
-                    break;
-            }
-        }
-
         @Override
         public void onClick(View v) {
             super.onClick(v);
@@ -509,7 +502,7 @@ public final class MainVideoPlayer extends Activity {
         @Override
         public boolean onSingleTapConfirmed(MotionEvent e) {
             if (DEBUG) Log.d(TAG, "onSingleTapConfirmed() called with: e = [" + e + "]");
-            if (playerImpl.getCurrentState() != BasePlayer.STATE_PLAYING) return true;
+            if (playerImpl.getCurrentState() == BasePlayer.STATE_BLOCKED) return true;
 
             if (playerImpl.isControlsVisible()) playerImpl.hideControls(150, 0);
             else {

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

@@ -111,7 +111,8 @@ public final class PopupVideoPlayer extends Service {
     private float minimumWidth, minimumHeight;
     private float maximumWidth, maximumHeight;
 
-    private final String setAlphaMethodName = (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) ? "setImageAlpha" : "setAlpha";
+    private final String setImageResourceMethodName = "setImageResource";
+
     private NotificationManager notificationManager;
     private NotificationCompat.Builder notBuilder;
     private RemoteViews notRemoteView;
@@ -255,18 +256,7 @@ public final class PopupVideoPlayer extends Service {
         notRemoteView.setOnClickPendingIntent(R.id.notificationRepeat,
                 PendingIntent.getBroadcast(this, NOTIFICATION_ID, new Intent(ACTION_REPEAT), PendingIntent.FLAG_UPDATE_CURRENT));
 
-        switch (playerImpl.simpleExoPlayer.getRepeatMode()) {
+        setRepeatModeRemote(notRemoteView, playerImpl.simpleExoPlayer.getRepeatMode());
-            case Player.REPEAT_MODE_OFF:
-                notRemoteView.setInt(R.id.notificationRepeat, setAlphaMethodName, 77);
-                break;
-            case Player.REPEAT_MODE_ONE:
-                //todo change image
-                notRemoteView.setInt(R.id.notificationRepeat, setAlphaMethodName, 168);
-                break;
-            case Player.REPEAT_MODE_ALL:
-                notRemoteView.setInt(R.id.notificationRepeat, setAlphaMethodName, 255);
-                break;
-        }
 
         return new NotificationCompat.Builder(this, getString(R.string.notification_channel_id))
                 .setOngoing(true)
@@ -370,6 +360,20 @@ public final class PopupVideoPlayer extends Service {
         windowManager.updateViewLayout(playerImpl.getRootView(), windowLayoutParams);
     }
 
+    protected void setRepeatModeRemote(final RemoteViews remoteViews, final int repeatMode) {
+        switch (repeatMode) {
+            case Player.REPEAT_MODE_OFF:
+                remoteViews.setInt(R.id.notificationRepeat, setImageResourceMethodName, R.drawable.exo_controls_repeat_off);
+                break;
+            case Player.REPEAT_MODE_ONE:
+                remoteViews.setInt(R.id.notificationRepeat, setImageResourceMethodName, R.drawable.exo_controls_repeat_one);
+                break;
+            case Player.REPEAT_MODE_ALL:
+                remoteViews.setInt(R.id.notificationRepeat, setImageResourceMethodName, R.drawable.exo_controls_repeat_all);
+                break;
+        }
+    }
+
     ///////////////////////////////////////////////////////////////////////////
 
     private class VideoPlayerImpl extends VideoPlayer {
@@ -435,27 +439,6 @@ public final class PopupVideoPlayer extends Service {
             stopSelf();
         }
 
-        @Override
-        public void onRepeatClicked() {
-            super.onRepeatClicked();
-            switch (simpleExoPlayer.getRepeatMode()) {
-                case Player.REPEAT_MODE_OFF:
-                    // Drawable didn't work on low API :/
-                    //notRemoteView.setImageViewResource(R.id.notificationRepeat, R.drawable.ic_repeat_disabled_white);
-                    // Set the icon to 30% opacity - 255 (max) * .3
-                    notRemoteView.setInt(R.id.notificationRepeat, setAlphaMethodName, 77);
-                    break;
-                case Player.REPEAT_MODE_ONE:
-                    // todo change image
-                    notRemoteView.setInt(R.id.notificationRepeat, setAlphaMethodName, 168);
-                    break;
-                case Player.REPEAT_MODE_ALL:
-                    notRemoteView.setInt(R.id.notificationRepeat, setAlphaMethodName, 255);
-                    break;
-            }
-            updateNotification(-1);
-        }
-
         @Override
         public void onDismiss(PopupMenu menu) {
             super.onDismiss(menu);
@@ -482,6 +465,16 @@ public final class PopupVideoPlayer extends Service {
                 hideControls(100, 0);
             }
         }
+        /*//////////////////////////////////////////////////////////////////////////
+        // ExoPlayer Video Listener
+        //////////////////////////////////////////////////////////////////////////*/
+
+        @Override
+        public void onRepeatModeChanged(int i) {
+            super.onRepeatModeChanged(i);
+            setRepeatModeRemote(notRemoteView, i);
+            updateNotification(-1);
+        }
 
         /*//////////////////////////////////////////////////////////////////////////
         // Playback Listener

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

@@ -211,7 +211,9 @@ public abstract class VideoPlayer extends BasePlayer implements SimpleExoPlayer.
         simpleExoPlayer.setVideoSurfaceView(surfaceView);
         simpleExoPlayer.addVideoListener(this);
 
-        trackSelector.setTunnelingAudioSessionId(C.generateAudioSessionIdV21(context));
+        if (Build.VERSION.SDK_INT >= 21) {
+            trackSelector.setTunnelingAudioSessionId(C.generateAudioSessionIdV21(context));
+        }
     }
 
     @Override
@@ -286,6 +288,7 @@ public abstract class VideoPlayer extends BasePlayer implements SimpleExoPlayer.
 
         qualityPopupMenu.setOnMenuItemClickListener(this);
         qualityPopupMenu.setOnDismissListener(this);
+        qualityTextView.setVisibility(View.VISIBLE);
     }
 
     private void buildPlaybackSpeedMenu() {
@@ -409,12 +412,8 @@ public abstract class VideoPlayer extends BasePlayer implements SimpleExoPlayer.
     public void onTracksChanged(TrackGroupArray trackGroups, TrackSelectionArray trackSelections) {
         super.onTracksChanged(trackGroups, trackSelections);
 
-        if (trackSelector.getCurrentMappedTrackInfo() == null) {
+        if (trackSelector.getCurrentMappedTrackInfo() == null) return;
-            qualityTextView.setVisibility(View.GONE);
+        qualityTextView.setVisibility(View.GONE);
-            return;
-        } else {
-            qualityTextView.setVisibility(View.VISIBLE);
-        }
 
         for (int t = 0; t < simpleExoPlayer.getRendererCount(); t++) {
             if (simpleExoPlayer.getRendererType(t) == C.TRACK_TYPE_VIDEO) {
@@ -422,9 +421,11 @@ public abstract class VideoPlayer extends BasePlayer implements SimpleExoPlayer.
             }
         }
         videoTrackGroups = trackSelector.getCurrentMappedTrackInfo().getTrackGroups(videoRendererIndex);
-        selectedVideoTrackGroup = trackSelections.get(videoRendererIndex).getTrackGroup();
+        final TrackSelection trackSelection = trackSelections.get(videoRendererIndex);
-
+        if (trackSelection != null) {
-        buildQualityMenu();
+            selectedVideoTrackGroup = trackSelection.getTrackGroup();
+            buildQualityMenu();
+        }
     }
 
     @Override

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

@@ -57,6 +57,14 @@ public class NavigationHelper {
                 .putExtra(VideoPlayer.PLAY_QUEUE, playQueue);
     }
 
+    public static Intent getPlayerIntent(final Context context,
+                                         final Class targetClazz,
+                                         final PlayQueue playQueue,
+                                         final boolean isAppending) {
+        return getPlayerIntent(context, targetClazz, playQueue)
+                .putExtra(BasePlayer.APPEND_ONLY, isAppending);
+    }
+
     public static Intent getPlayerIntent(final Context context,
                                          final Class targetClazz,
                                          final PlayQueue playQueue,

app/src/main/res/layout/activity_background_player.xml

@@ -183,6 +183,23 @@
             android:src="@drawable/ic_pause_white"
             tools:ignore="ContentDescription"/>
 
+        <ProgressBar
+            android:id="@+id/control_progress_bar"
+            style="?android:attr/progressBarStyleLargeInverse"
+            android:layout_width="50dp"
+            android:layout_height="match_parent"
+            android:layout_centerVertical="true"
+            android:layout_centerHorizontal="true"
+            android:layout_centerInParent="true"
+            android:layout_marginLeft="5dp"
+            android:layout_marginRight="5dp"
+            android:background="#00000000"
+            android:padding="2dp"
+            android:clickable="false"
+            android:scaleType="fitCenter"
+            android:indeterminate="true"
+            android:visibility="invisible"/>
+
         <ImageButton
             android:id="@+id/control_forward"
             android:layout_width="40dp"

app/src/main/res/layout/activity_main_player.xml

@@ -155,7 +155,7 @@
                     android:clickable="true"
                     android:padding="5dp"
                     android:scaleType="fitXY"
-                    android:src="@drawable/ic_repeat_white"
+                    android:src="@drawable/exo_controls_repeat_off"
                     tools:ignore="ContentDescription,RtlHardcoded"/>
 
                 <ImageButton