Crashes when closing the App while audio is playing

[iRahulGaur]

Steps to reproduce

1. Play audio
2. Close App from task menu

Error Log

java.lang.NullPointerException: Attempt to invoke virtual method 'long com.google.android.exoplayer2.SimpleExoPlayer.getContentPosition()' on a null object reference
    at com.thealien.myaudioplayer.player.MediaPlayerAdapter$1.run(MediaPlayerAdapter.java:188)

Fix

//the getDuration method returns a negative one when the audio is stopped
// add this condition at line 188 in MediaPlayerAdapter.java
if (exoPlayer != null && exoPlayer.getContentPosition() >= exoPlayer.getDuration() && exoPlayer.getDuration() > 0) {
    playbackInfoListener.onPlaybackComplete();
}