-Fixed audio focus not working with timeline changes.

-Changed circular loading to boundary loading.

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

@@ -440,12 +440,16 @@ public abstract class BasePlayer implements Player.EventListener,
         if (simpleExoPlayer != null) simpleExoPlayer.setVolume(DUCK_AUDIO_TO);
         animateAudio(DUCK_AUDIO_TO, 1f, DUCK_DURATION);
 
-        if (isResumeAfterAudioFocusGain()) simpleExoPlayer.setPlayWhenReady(true);
+        if (isResumeAfterAudioFocusGain()) {
+            simpleExoPlayer.setPlayWhenReady(true);
+            wasPlaying = true;
+        }
     }
 
     protected void onAudioFocusLoss() {
         if (DEBUG) Log.d(TAG, "onAudioFocusLoss() called");
         simpleExoPlayer.setPlayWhenReady(false);
+        wasPlaying = false;
     }
 
     protected void onAudioFocusLossCanDuck() {
@@ -758,6 +762,7 @@ public abstract class BasePlayer implements Player.EventListener,
             else playQueue.setIndex(0);
         }
         simpleExoPlayer.setPlayWhenReady(!isPlaying());
+        wasPlaying = simpleExoPlayer.getPlayWhenReady();
     }
 
     public void onFastRewind() {
@@ -774,10 +779,12 @@ public abstract class BasePlayer implements Player.EventListener,
         if (simpleExoPlayer == null || playQueue == null || currentInfo == null) return;
         if (DEBUG) Log.d(TAG, "onPlayPrevious() called");
 
-        if (simpleExoPlayer.getCurrentPosition() <= PLAY_PREV_ACTIVATION_LIMIT) {
+        /* If current playback has run for PLAY_PREV_ACTIVATION_LIMIT milliseconds, restart current track.
-            playQueue.offsetIndex(-1);
+        * Also restart the track if the current track is the first in a queue.*/
-        } else {
+        if (simpleExoPlayer.getCurrentPosition() > PLAY_PREV_ACTIVATION_LIMIT || playQueue.getIndex() == 0) {
             simpleExoPlayer.seekTo(currentInfo.start_position);
+        } else {
+            playQueue.offsetIndex(-1);
         }
     }
 

app/src/main/java/org/schabi/newpipe/player/playback/PlaybackManager.java

@@ -211,18 +211,18 @@ public class PlaybackManager {
         // The current item has higher priority
         final int currentIndex = playQueue.getIndex();
         final PlayQueueItem currentItem = playQueue.get(currentIndex);
-        if (currentItem != null) load(currentItem);
+        if (currentItem == null) return;
-        else return;
+        load(currentItem);
+
+        // Load boundaries to ensure correct looping
+        if (sourceToQueueIndex.indexOf(0) == -1) load(playQueue.get(0));
+        if (sourceToQueueIndex.indexOf(playQueue.size() - 1) == -1) load(playQueue.get(playQueue.size() - 1));
 
         // The rest are just for seamless playback
         final int leftBound = Math.max(0, currentIndex - WINDOW_SIZE);
-        final int rightLimit = currentIndex + WINDOW_SIZE + 1;
+        final int rightBound = Math.min(playQueue.size(), currentIndex + WINDOW_SIZE + 1);
-        final int rightBound = Math.min(playQueue.size(), rightLimit);
         final List<PlayQueueItem> items = new ArrayList<>(playQueue.getStreams().subList(leftBound, rightBound));
 
-        final int excess = rightLimit - playQueue.size();
-        if (excess >= 0) items.addAll(playQueue.getStreams().subList(0, excess));
-
         for (final PlayQueueItem item: items) load(item);
     }
 
@@ -245,7 +245,7 @@ public class PlaybackManager {
                 final MediaSource source = playbackListener.sourceOf(streamInfo, item.getSortedQualityIndex());
                 final int itemIndex = playQueue.indexOf(item);
                 // replace all except the currently playing
-                insert(itemIndex, source, false);
+                insert(itemIndex, source, itemIndex != playQueue.getIndex());
                 if (tryUnblock()) sync();
             }