android 调用系统的音乐和视频播放器

package com.eboy.testsystemaudiovideo;

import android.app.Activity;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class MainActivity extends Activity {

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        Button btnAudio = (Button) this.findViewById(R.id.button1);        
        
        btnAudio.setOnClickListener(new OnClickListener() {
            
            @Override
            public void onClick(View v) {
                Intent it = new Intent(Intent.ACTION_VIEW);
                it.setDataAndType(Uri.parse("file://" + Environment.getExternalStorageDirectory() + "/a.MP3"), "audio/MP3");
                startActivity(it);            
            }
        });
        
        Button btnVideo = (Button) this.findViewById(R.id.button2);
        
        btnVideo.setOnClickListener(new OnClickListener() {
            
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(Intent.ACTION_VIEW);
                intent.setDataAndType(Uri.parse(Environment.getExternalStorageDirectory() + "/3.mp4"), "video/mp4");
                startActivity(intent);
            }
        });
    }
}