Android播放视频

package cn.c;
import java.io.File;
import java.io.IOException;
import android.app.Activity;
import android.media.MediaPlayer;
import android.media.MediaPlayer.OnCompletionListener;
import android.media.MediaPlayer.OnErrorListener;
import android.media.MediaPlayer.OnInfoListener;
import android.media.MediaPlayer.OnPreparedListener;
import android.media.MediaPlayer.OnSeekCompleteListener;
import android.media.MediaPlayer.OnVideoSizeChangedListener;
import android.os.Bundle;
import android.os.Environment;
import android.view.Display;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.widget.LinearLayout;

public class MainActivity extends Activity implements
OnCompletionListener,OnErrorListener,OnInfoListener,OnPreparedListener,
OnSeekCompleteListener,OnVideoSizeChangedListener,SurfaceHolder.Callback{
private SurfaceView mSurfaceView;
private SurfaceHolder mSurfaceHolder;
private Display mDisplay;
private MediaPlayer mMediaPlayer;
int videoWidth=0;
int videoHeight=0;

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
mDisplay=getWindowManager().getDefaultDisplay();
mSurfaceView=(SurfaceView) findViewById(R.id.surfaceView);
mSurfaceHolder=mSurfaceView.getHolder();
//SurfaceHolder是用于管理SurfaceView对象
//那它是怎么做到管理的呢?即用mSurfaceHolder
//添加回调即addCallback.
//该类实现了SurfaceHolder.Callback接口,所以addCallback(this)
//在SurfaceHolder.Callback接口中一共有三个方法来实现对于
//SurfaceView对象的管理,即:
//surfaceCreated()
//surfaceChanged()
//surfaceDestroyed()
//概况:SurfaceHolder主要作用是监控底层的情况
mSurfaceHolder.addCallback(this);
mSurfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);

mMediaPlayer=new MediaPlayer();
mMediaPlayer.setOnCompletionListener(this);
mMediaPlayer.setOnErrorListener(this);
mMediaPlayer.setOnInfoListener(this);
mMediaPlayer.setOnPreparedListener(this);
mMediaPlayer.setOnSeekCompleteListener(this);
mMediaPlayer.setOnVideoSizeChangedListener(this);
String path=Environment.getExternalStorageDirectory().getPath()
+File.separator+"Test_Movie.m4v";
try {
//设置MediaPlayer将要播放的视频
mMediaPlayer.setDataSource(path);
} catch (IllegalArgumentException e) {
e.printStackTrace();
finish();
} catch (IllegalStateException e) {
e.printStackTrace();
finish();
} catch (IOException e) {
e.printStackTrace();
finish();
}
}
//来自于SurfaceHolder.Callback接口
//创建SurfaceView完成时,会调用该方法
public void surfaceCreated(SurfaceHolder holder) {
//设置MediaPlayer的视频输出界面
//只显示音频而不显示视频时可不调用这个方法
mMediaPlayer.setDisplay(mSurfaceHolder);
try {
//准备播放,调用mMediaPlayer.prepareAsync();
//方法后会执行覆写后的
//public void onPrepared(MediaPlayer mp)
//注意:
//也可调用prepare()解码,但为一个同步的操作
mMediaPlayer.prepareAsync();
} catch (Exception e) {
e.printStackTrace();
finish();
}
}
//来自于SurfaceHolder.Callback接口
//当SurfaceView的宽度,高度或其他参数发生变化时,会调用该方法
public void surfaceChanged(SurfaceHolder holder,
int format, int width,int height) {

}
//来自于SurfaceHolder.Callback接口
//当SurfaceView摧毁时,会调用该方法
public void surfaceDestroyed(SurfaceHolder holder) {

}
//来自于MediaPlayer.OnVideoSizeChangedListener接口
//当视频的宽度或高度发生变化时调用该方法
public void onVideoSizeChanged(MediaPlayer mp, int width, int height) {

}
//来自于MediaPlayer.OnSeekCompleteListener接口
public void onSeekComplete(MediaPlayer mp) {

}
//来自于MediaPlayer.OnPreparedListener接口
//一旦调用该方法,MediaPlayer就进入了"准备就绪"
//状态,准备开始播放.
//此处可用于动态设置SurfaceView的宽和高!!!
public void onPrepared(MediaPlayer mediaPlayer) {
videoWidth=mediaPlayer.getVideoWidth();
videoHeight=mediaPlayer.getVideoHeight();
if (videoWidth > mDisplay.getWidth()|| videoHeight > mDisplay.getHeight()) {
float heightRatio = (float) videoHeight/ (float) mDisplay.getHeight();
float widthRatio = (float) videoWidth/ (float) mDisplay.getWidth();
if (heightRatio > 1 || widthRatio > 1) {
if (heightRatio > widthRatio) {
videoHeight = (int) Math.ceil((float) videoHeight/ (float) heightRatio);
videoWidth = (int) Math.ceil((float) videoWidth/ (float) heightRatio);
} else {
videoHeight = (int) Math.ceil((float) videoHeight/ (float) widthRatio);
videoWidth = (int) Math.ceil((float) videoWidth/ (float) widthRatio);
}
}
}
//设置SurfaceView的宽和高
mSurfaceView.setLayoutParams
(new LinearLayout.LayoutParams(videoWidth,videoHeight));
//MediaPlayer开始播放
mediaPlayer.start();
}
//来自于MediaPlayer.OnInfoListener接口
//当出现关于播放媒体的特定信息或者需要发出警告的时候
//将调用该方法
//比如开始缓冲、缓冲结束、下载速度变化(该行待验证)
//小结:这些Info都是以MediaPlayer.MEDIA_INFO_开头的
public boolean onInfo(MediaPlayer mp, int what, int extra) {
if (what==MediaPlayer.MEDIA_INFO_BAD_INTERLEAVING) {
//音频和视频数据不正确地交错时将出现该提示信息.在一个
//正确交错的媒体文件中,音频和视频样本将依序排列,从而
//使得播放可以有效和平稳地进行
}
if (what==MediaPlayer.MEDIA_INFO_NOT_SEEKABLE) {
//当媒体不能正确定位时将出现该提示信息.
//此时意味着它可能是一个在线流
}
if (what==MediaPlayer.MEDIA_INFO_VIDEO_TRACK_LAGGING) {
//当设备无法播放视频时将出现该提示信息
//比如视频太复杂或者码率过高
}
if (what==MediaPlayer.MEDIA_INFO_METADATA_UPDATE) {
//当新的元数据可用时将出现该提示信息
}
if (what==MediaPlayer.MEDIA_INFO_UNKNOWN) {
//其余不可知提示信息
}
return false;
}
//来自于MediaPlayer.OnErrorListener接口
//MediaPlayer发生错误时会调用该方法
//只有如下这三种错误.
//小结:这些错误都是以MediaPlayer.MEDIA_ERROR.开头的
public boolean onError(MediaPlayer mp, int what, int extra) {
if (what==MediaPlayer.MEDIA_ERROR_NOT_VALID_FOR_PROGRESSIVE_PLAYBACK) {
System.out.println("第一种错误");
}
if (what==MediaPlayer.MEDIA_ERROR_SERVER_DIED) {
System.out.println("第二种错误");
}
if (what==MediaPlayer.MEDIA_ERROR_UNKNOWN) {
System.out.println("第三种错误");
}
return false;
}
//来自于MediaPlayer.OnCompletionListener接口
//当MediaPlayer播放完文件时,会调用该方法.
//此时可以进行一些其他的操作比如:播放下一个视频
public void onCompletion(MediaPlayer mp) {
finish();
}
}