Android写一个视频播放器

Android中实现视频播放器可以通过以下步骤：

1. 在布局文件中添加一个SurfaceView用来展示视频：

<SurfaceView
    android:id="@+id/surface_view"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />

2. 在Activity中获取SurfaceView并设置MediaPlayer：

public class VideoPlayerActivity extends AppCompatActivity implements SurfaceHolder.Callback {
    private MediaPlayer mediaPlayer;
    private SurfaceView surfaceView;
    private SurfaceHolder surfaceHolder;

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

        surfaceView = findViewById(R.id.surface_view);
        surfaceHolder = surfaceView.getHolder();
        surfaceHolder.addCallback(this);

        mediaPlayer = new MediaPlayer();
        mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
    }

    @Override
    public void surfaceCreated(SurfaceHolder holder) {
        mediaPlayer.setDisplay(holder);
        try {
            mediaPlayer.setDataSource("video_path");
            mediaPlayer.prepare();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    @Override
    public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
    }

    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {
        mediaPlayer.release();
    }
}

3. 添加控制按钮来控制视频播放：

public void play(View view) {
    mediaPlayer.start();
}

public void pause(View view) {
    mediaPlayer.pause();
}

public void stop(View view) {
    mediaPlayer.stop();
    mediaPlayer.prepareAsync();
}

需要注意的是，视频播放器的具体实现可能因应用场景不同而有所差异，例如添加进度条、全屏播放等功能。