问无法在android中使用videoview播放rtsp

EN

package com.ashley.work;

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.MenuItem;
import android.support.v4.app.NavUtils;
import android.app.Activity;  
import android.net.Uri;  
import android.os.Bundle;  
import android.view.View;  
import android.widget.Button;  
import android.widget.EditText;  
import android.widget.VideoView;  


public class TestPlayRTSP extends Activity {

Button playButton ;  
VideoView videoView ;  

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_test_play_rtsp);

    videoView = (VideoView)this.findViewById(R.id.myvideoview);  

    playButton = (Button)this.findViewById(R.id.button1);  
    playButton.setOnClickListener(new Button.OnClickListener(){  
    public void onClick(View v) {  
    PlayRtspStream("rtsp://140.xxx.xxx.xxx:8554/");  
    }  
    });  


}

private void PlayRtspStream(String rtspUrl){  
    videoView.setVideoURI(Uri.parse(rtspUrl));  
    videoView.requestFocus();  
    videoView.start();  
}  

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.activity_test_play_rtsp, menu);
    return true;
}