MediaPlayer 用法(1)

使用SurfaceView播放视频,其实很简单,但是经常会碰见有声音没图像的问题.

其实使用SurfaceView播放视频只需要主要下面几个地方就可以了

1. surfaceChanged也就是Suface是否创建成功

2. onPrepared 也就是MideoPlayer是否加载并准备完成

3. surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);

类型必须是SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS

package VideoTest.Test;

import java.io.FileDescriptor;

import android.app.Activity;
import android.content.res.AssetFileDescriptor;
import android.media.AudioManager;
import android.media.MediaPlayer;
import android.media.MediaPlayer.OnBufferingUpdateListener;
import android.media.MediaPlayer.OnCompletionListener;
import android.media.MediaPlayer.OnPreparedListener;
import android.os.Bundle;
import android.view.SurfaceHolder;
import android.view.SurfaceView;


public class VideoTest extends Activity implements SurfaceHolder.Callback, 
	OnBufferingUpdateListener, OnCompletionListener, OnPreparedListener{
	
	private SurfaceView surfaceView;
	private SurfaceHolder surfaceHolder;
	private MediaPlayer mediaPlayer;
	
	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		
		this.surfaceView = new SurfaceView(this);
		this.surfaceHolder = this.surfaceView.getHolder();
		this.surfaceHolder.addCallback(this);
		
		//类型必须设置成SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS
		this.surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);	
		setContentView(this.surfaceView);
	}
	
	@Override
	public void onDestroy() {
		super.onDestroy();
		if (this.mediaPlayer != null) {
			this.mediaPlayer.release();
			this.mediaPlayer = null;
		}
	}
	
	public void PlayVideo(){
		
		try {
			//视频文件放在 assert中
			AssetFileDescriptor aFD = this.getAssets().openFd("welcome.3gp");
			FileDescriptor fileDescriptor = aFD.getFileDescriptor();
			this.mediaPlayer = new MediaPlayer();
			this.mediaPlayer.setDataSource(fileDescriptor, aFD.getStartOffset(), aFD.getLength());
			aFD.close();	
			
			//视频放在SDCard中
			//File sdFile = Environment.getExternalStorageDirectory();
			//this.mediaPlayer = new MediaPlayer();
			//this.mediaPlayer.setDataSource(sdFile.getAbsoluteFile() + File.separator + "welcome.3gp");
			
			//视频放在res中
			//this.mediaPlayer = MediaPlayer.create(this, R.raw.welcome);
			
			//网上的视频,没有测试
			//this.mediaPlayer
			//	.setDataSource("http://xy2.163.com/download/down/wukong.mp3");
			
			this.mediaPlayer.setDisplay(this.surfaceHolder);
			this.mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
			//准备完成后才可以播放,另外如果文件特别大或者从网上获得的资源
			//会在这里等待时间过长,造成堵塞,这样的话就得用
			//this.mediaPlayer.prepareAsync(),然后监听是否准备完毕在开始
			
			this.mediaPlayer.prepare();			
			this.mediaPlayer.start();				
				
		} catch (Exception e) {
			// TODO: handle exception
		}
	}
	
	@Override
	public void surfaceChanged(SurfaceHolder holder, int format, int width,
			int height) {
		
	}

	@Override
	public void surfaceCreated(SurfaceHolder holder) {
		//SurfaceCreated 创建成功才可以播放视频
		PlayVideo();
	}

	@Override
	public void surfaceDestroyed(SurfaceHolder holder) {
		
	}
	
	//@Override
	public void onBufferingUpdate(MediaPlayer mp, int percent) {
		// TODO Auto-generated method stub

	}

	//@Override
	public void onCompletion(MediaPlayer mp) {
		// TODO Auto-generated method stub

	}

	//@Override
	public void onPrepared(MediaPlayer mp) {
		//MediaPlayer加载准备完毕才能开始播放
		//mp.start();
	}
	
}

但是,对于一些人可能会产生另一个问题就是

surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);

在设置成SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS类型后,无法画图了

SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS的意思是创建一个"PUSH"surface,这个surface没有自己的缓冲区,没有自己的缓冲Buffer.