谁能解释这个媒体控制器的代码?
videoview = (VideoView) findViewById(R.id.player);
videoview.setVideoURI(Uri.parse("android.resource://"+ getPackageName()+ "/" +R.raw.sample));
videoview.start();
MediaController controller = new MediaController(this);
controller.setMediaPlayer(videoview);
videoview.setMediaController(controller);