Android SurfaceView视频播放器黑屏

Question

我是android的新手，我正在尝试使用surfaceView创建一个简单的视频播放器。

我的xml：

    <?xml version="1.0" encoding="utf-8"?>
    <AbsoluteLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="800dp"
    android:layout_height="800dp"
    android:orientation="vertical" >

    <SurfaceView
        android:id="@+id/surfaceview"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
         />

</AbsoluteLayout>

我的代码：

public class MainActivity extends Activity 
implements SurfaceHolder.Callback {

MediaPlayer mediaPlayer;
SurfaceView surfaceView;
SurfaceHolder surfaceHolder;


@Override
protected void onCreate(Bundle savedInstanceState) 
{
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    getWindow().setFormat(PixelFormat.UNKNOWN);
    surfaceView = (SurfaceView)findViewById(R.id.surfaceview);
    surfaceHolder = surfaceView.getHolder();
    surfaceHolder.addCallback(this);
    surfaceHolder.setFixedSize(176, 144);

    surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
    mediaPlayer = new MediaPlayer();


}


@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width,
        int height) {
    // TODO Auto-generated method stub

}


@Override
public void surfaceCreated(SurfaceHolder holder) {
    // TODO Auto-generated method stub

    mediaPlayer.setDisplay(holder);
    play();
}


@Override
public void surfaceDestroyed(SurfaceHolder holder) {
    // TODO Auto-generated method stub

}

void play(){
    try {
    mediaPlayer.setDataSource("android.resource://"+getPackageName()+"/"+R.raw.video);

        mediaPlayer.prepare(); 

    } catch (IllegalArgumentException e) {
        e.printStackTrace();
    } catch (IllegalStateException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }
    mediaPlayer.start();
}   

我的问题是，视频不会启动只会出现黑屏，没有视频或声音。我做错了什么？有任何想法吗？谢谢你的帮助。

FIX：

File pathz = android.os.Environment.getExternalStorageDirectory();
mediaPlayer.setDataSource(pathz + "/Samsung/Video/Billiard_Domino.mp4");