Update PlayQueueActivity.java

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

@@ -97,7 +97,10 @@ public final class PlayQueueActivity extends AppCompatActivity
         getMenuInflater().inflate(R.menu.menu_play_queue, m);
         getMenuInflater().inflate(R.menu.menu_play_queue_bg, m);
         onMaybeMuteChanged();
+        // to avoid null reference
+        if (player != null) {
             onPlaybackParameterChanged(player.getPlaybackParameters());
+        }
         return true;
     }