判断了mediaPlayer!=null，调用seekTo()方法后依然抛NullpointException

[Beseting]

//looping->false SurfaceView
if (this.mediaPlayer != null) {// OnCompletionListener回调中执行
this.mediaPlayer.seekTo(0);
this.mediaPlayer.start();
}

java.lang.NullPointerException
Attempt to invoke virtual method 'void com.qiniu.qplayer.mediaEngine.MediaPlayer.seekTo(int)' on a null object reference