以下是活动代码

public class MainActivity extends Activity implements OnClickListener {

private SurfaceView surfaceView;
private Button btnPlay;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    init();
    addListener();

}

private void init() {
    // TODO Auto-generated method stub
    surfaceView = (SurfaceView) findViewById(R.id.surfaceView1);
    btnPlay = (Button) findViewById(R.id.btnPlay);
}

private void addListener() {
    // TODO Auto-generated method stub

    btnPlay.setOnClickListener(this);
}

MediaPlayer mediaPlayer = null;

@Override
public void onClick(View v) {
    // TODO Auto-generated method stub
    switch (v.getId()) {
    case R.id.btnPlay:
        try{
        if (mediaPlayer != null) {
            mediaPlayer.reset();
            mediaPlayer.release();
        }else{
        getWindow().setFormat(PixelFormat.UNKNOWN);
        MediaPlayer mediaPlayer = MediaPlayer.create(this,R.raw.wildlife);
        SurfaceHolder surfaceHolder = surfaceView.getHolder();

        surfaceHolder.setFixedSize(176,144);
        surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
        mediaPlayer.setDisplay(surfaceHolder);
        mediaPlayer.start();}
        }catch (Exception e) {
            Toast.makeText(getApplicationContext(),e.getMessage(),Toast.LENGTH_LONG).show();
        }
        break;

    default:
        break;
    }
  }
   }

以下是xml的布局代码

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity" >

<SurfaceView
    android:id="@+id/surfaceView1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentBottom="true"
    android:layout_alignParentLeft="true"
    android:layout_alignParentRight="true"
    android:layout_alignParentTop="true" />

<Button
    android:id="@+id/btnPlay"
    style="?android:attr/buttonStyleSmall"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignRight="@+id/surfaceView1"
    android:layout_alignTop="@+id/surfaceView1"
    android:text="@string/play" />

</RelativeLayout>

请告诉我需要做什么？
提前致谢.