Android开发之MediaPlayer和SurfaceView组成视频播放器

SurfaceView 

• 使用双缓冲技术
• 是个重量级的组件
• 只要不可见，就不会创建，可见时，才会创建
• 只要不可见，就会销毁

 SurfaceView一旦不可见，就会被销毁，一旦可见，就会被创建，销毁时停止播放，再次创建时再开始播放

import android.app.Activity;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.view.SurfaceHolder;
import android.view.SurfaceHolder.Callback;
import android.view.SurfaceView;

public class MainActivity extends Activity {
    private MediaPlayer player;
    static int currentPosition;

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

        SurfaceView sv = (SurfaceView) findViewById(R.id.sv);
        // 拿到surfaceview的控制器
        final SurfaceHolder sh = sv.getHolder();
        //给SurfaceHolder设置CallBack，类似于侦听，可以知道SurfaceView的状态
        sh.addCallback(new Callback() {
            // surfaceView销毁时调用
            @Override
            public void surfaceDestroyed(SurfaceHolder holder) {
                // 每次surfaceview销毁时，同时停止播放视频
                if (player != null) {
                    currentPosition = player.getCurrentPosition();
                    player.stop();
                    player.release();
                    player = null;
                }
            }

            // surfaceView创建时调用
            @Override
            public void surfaceCreated(SurfaceHolder holder) {
                // 每次surfaceView创建时才去播放视频
                if (player == null) {
                    player = new MediaPlayer();
                    player.reset();
                    try {
                        player.setDataSource("sdcard/2.3gp");
                        player.setDisplay(sh);
                        player.prepare();
                        player.start();
                        player.seekTo(currentPosition);
                    } catch (Exception e) {
                        e.printStackTrace();
                    }
                }

            }

            // surfaceView结构改变时调用
            @Override
            public void surfaceChanged(SurfaceHolder holder, int format,
                    int width, int height) {
            }
        });
    }
}