Android播放本地视频

主程序
public class MainActivity extends AppCompatActivity implements View.OnClickListener {

private MediaPlayer mediaPlayer = new MediaPlayer();

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

    Button btnPlay = (Button) findViewById(R.id.btnPlay);
    Button btnPause = (Button) findViewById(R.id.btnPause);
    Button btnStop = (Button) findViewById(R.id.btnStop);

    btnPlay.setOnClickListener(this);
    btnPause.setOnClickListener(this);
    btnStop.setOnClickListener(this);


    //权限判断，如果没有权限就请求权限
    if (ContextCompat.checkSelfPermission(MainActivity.this, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
        ActivityCompat.requestPermissions(MainActivity.this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, 1);
    } else {
        initMediaPlayer();//初始化播放器 MediaPlayer
    }


}

private void initMediaPlayer() {
    try {
        File file = new File(Environment.getExternalStorageDirectory(), "music.mp3");
        mediaPlayer.setDataSource(file.getPath()+"/"+R.raw.a);//指定音频文件路径
        mediaPlayer.setLooping(true);//设置为循环播放
        mediaPlayer.prepare();//初始化播放器MediaPlayer

    } catch (Exception e) {
        e.printStackTrace();
    }
}

@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
    switch (requestCode){
        case 1:
            if(grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED){
                initMediaPlayer();
            }else{
                Toast.makeText(this, "拒绝权限，将无法使用程序。", Toast.LENGTH_LONG).show();
                finish();
            }
            break;
        default:
    }

}

@Override
public void onClick(View v) {
    switch (v.getId()){
        case R.id.btnPlay:

            //如果没在播放中，立刻开始播放。
            if(!mediaPlayer.isPlaying()){
                mediaPlayer.start();
            }
            break;
        case R.id.btnPause:
            //如果在播放中，立刻暂停。
            if(mediaPlayer.isPlaying()){
                mediaPlayer.pause();
            }
            break;
        case R.id.btnStop:
            //如果在播放中，立刻停止。
            if(mediaPlayer.isPlaying()){
                mediaPlayer.reset();
                initMediaPlayer();//初始化播放器 MediaPlayer
            }
            break;
        default:
            break;
    }
}

@Override
protected void onDestroy() {
    super.onDestroy();
    if(mediaPlayer != null){
        mediaPlayer.stop();
        mediaPlayer.release();
    }
}

}

main布局文件

<?xml version="1.0" encoding="utf-8"?>

<Button
    android:id="@+id/btnPlay"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:textAllCaps="false"
    android:text="Play"/>
<Button
    android:id="@+id/btnPause"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:textAllCaps="false"
    android:text="Pause"/>
<Button
    android:id="@+id/btnStop"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:textAllCaps="false"
    android:text="Stop"/>