Android视频播放-SurfaceView和Mediaplayer
好几天没写博客了,处理了一点个人私事加上平时加班,基本上时间不充裕,上篇文章讲了一下用Mediaplayer来播放音乐,这次就讲讲使用Mediaplayer来和SurfaceView配合播放一个视频流媒体。MediaPlayer不仅可以播放视频,还可以与SurfaceView的配合,SurfaceView主要用于显示MediaPlayer播放的视频流媒体的画面渲染,两者可以一起协同播放视频。
基础维护
先来看下要实现的界面:
如果你看过上篇文章,就发现其实很简单的就是多了一个进度条,还有一个就是SurfaceView,就是下面那块黑色区域;
布局文件代码:
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<LinearLayout xmlns:android= "http://schemas.android.com/apk/res/android"
xmlns:tools= "http://schemas.android.com/tools"
android:layout_width= "match_parent"
android:layout_height= "match_parent"
android:orientation= "vertical"
tools:context= "com.example.googlevideo.MainActivity" >
<EditText
android:id= "@+id/edit_musicPath"
android:layout_width= "match_parent"
android:layout_height= "wrap_content"
android:hint= "输入MV的路径" />
<SeekBar
android:id= "@+id/seekBar_video"
android:layout_width= "match_parent"
android:layout_height= "wrap_content" />
<LinearLayout
android:layout_width= "match_parent"
android:layout_height= "wrap_content"
android:orientation= "horizontal" >
<Button
android:id= "@+id/btn_Play"
android:layout_width= "wrap_content"
android:layout_height= "wrap_content"
android:onClick= "playEvent"
android:text= "播放" />
<Button
android:id= "@+id/btn_Pause"
android:layout_width= "wrap_content"
android:layout_height= "wrap_content"
android:onClick= "pauseEvent"
android:text= "暂停" />
<Button
android:id= "@+id/btn_Stop"
android:layout_width= "wrap_content"
android:layout_height= "wrap_content"
android:onClick= "stopEvent"
android:text= "停止" />
<Button
android:id= "@+id/btn_Replay"
android:layout_width= "wrap_content"
android:layout_height= "wrap_content"
android:onClick= "replayEvent"
android:text= "重播" />
</LinearLayout>
<SurfaceView
android:id= "@+id/surface_video"
android:layout_width= "match_parent"
android:layout_height= "match_parent" />
</LinearLayout> |
Demo实现
实现Demo之前应该讲讲视频播放的原理,先确定视频的格式,这个和解码相关,不同的格式视频编码不同,然后通过编码格式进行解码,最后得到一帧一帧的图像,并把这些图像快速的显示在界面上,即为播放一段视频。SurfaceView在Android中就是完成这个功能的。SurfaceView是配合MediaPlayer使用的,MediaPlayer也提供了相应的方法设置SurfaceView显示图片,只需要为MediaPlayer指定SurfaceView显示图像即可。它的完整签名:void setDisplay(SurfaceHolder sh)。它需要传递一个SurfaceHolder对象,SurfaceHolder可以理解为SurfaceView装载需要显示的一帧帧图像的容器,它可以通过SurfaceHolder.getHolder()方法获得。使用MediaPlayer配合SurfaceView播放视频的步骤与播放使用MediaPlayer播放MP3大体一致,只需要额外设置显示的SurfaceView即可。
先准备一段能播放的视频:
播放视频效果图:
代码如下:
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editText = (EditText) findViewById(R.id.edit_musicPath); pathString = editText.getText().toString().trim();
File file = new File(pathString);
if (file.exists()) {
try {
mediaPlayer = new MediaPlayer();
mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
mediaPlayer.setDataSource(pathString);
//通过SurfaceView获取的Holder
mediaPlayer.setDisplay(holder);
mediaPlayer.prepare();
mediaPlayer.start();
btn_PlayButton.setEnabled( false );
//设置Bar的最大值
int max=mediaPlayer.getDuration();
seekBarVideo.setMax(max);
//定时器更新进度条
timer= new Timer();
timeTask= new TimerTask() {
@Override
public void run() {
// TODO Auto-generated method stub
seekBarVideo.setProgress(mediaPlayer.getCurrentPosition());
}
};
timer.schedule(timeTask, 0 , 500 );
//视频播放完之后重新设置显示
mediaPlayer.setOnCompletionListener( new OnCompletionListener() {
@Override
public void onCompletion(MediaPlayer mp) {
// TODO Auto-generated method stub
btn_PlayButton.setEnabled( true );
}
});
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
} else {
Toast.makeText( this , "Sorry,你输入的路径有问题,请仔细检查" , Toast.LENGTH_SHORT)
.show();
}
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SeekBar的使用:
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//设置Bar的最大值 int max=mediaPlayer.getDuration();
seekBarVideo.setMax(max);
//定时器更新进度条
timer= new Timer();
timeTask= new TimerTask() {
@Override
public void run() {
// TODO Auto-generated method stub
seekBarVideo.setProgress(mediaPlayer.getCurrentPosition());
}
};
timer.schedule(timeTask, 0 , 500 );
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其中holder是SurfaceHolder,在onCreate中获取:
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surfaceView = (SurfaceView) findViewById(R.id.surface_video); holder = surfaceView.getHolder();
//兼容4.0以后的手机版本,本身是不维护的
holder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
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如果正在播放视频,最小化的时候是会有声音的,需要在回调函数中处理一下:
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holder.addCallback( new Callback() {
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
// TODO Auto-generated method stub
Log.i(tag, "销毁了Holder" );
if (mediaPlayer!= null &&mediaPlayer.isPlaying()) {
currentPosition=mediaPlayer.getCurrentPosition();
mediaPlayer.stop();
mediaPlayer.release();
mediaPlayer= null ;
timer.cancel();
timeTask.cancel();
timer= null ;
timeTask= null ;
}
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
// TODO Auto-generated method stub
Log.i(tag, "创建了Holder" );
if (currentPosition> 0 ) {
try {
mediaPlayer = new MediaPlayer();
mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
mediaPlayer.setDataSource(pathString);
//通过SurfaceView获取的Holder
mediaPlayer.setDisplay(holder);
mediaPlayer.prepare();
mediaPlayer.start();
mediaPlayer.seekTo(currentPosition);
btn_PlayButton.setEnabled( false );
//视频播放完之后重新设置显示
mediaPlayer.setOnCompletionListener( new OnCompletionListener() {
@Override
public void onCompletion(MediaPlayer mp) {
// TODO Auto-generated method stub
btn_PlayButton.setEnabled( true );
}
});
int max=mediaPlayer.getDuration();
seekBarVideo.setMax(max);
//定时器更新进度条
timer= new Timer();
timeTask= new TimerTask() {
@Override
public void run() {
// TODO Auto-generated method stub
seekBarVideo.setProgress(mediaPlayer.getCurrentPosition());
}
};
timer.schedule(timeTask, 0 , 500 );
} catch (Exception e) {
// TODO: handle exception
}
}
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width,
int height) {
// TODO Auto-generated method stub
Log.i(tag, "改变了Holder" );
}
}); |
进度条是SeekBar,如果需要快进或者后退的时候是需要将焦点赋值给mediaPlayer的:
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seekBarVideo=(SeekBar) findViewById(R.id.seekBar_video); seekBarVideo.setOnSeekBarChangeListener( new OnSeekBarChangeListener() {
@Override
public void onStopTrackingTouch(SeekBar seekBar) {
// TODO Auto-generated method stub
int position=seekBar.getProgress();
if (mediaPlayer!= null &&mediaPlayer.isPlaying()) {
mediaPlayer.seekTo(position);
}
}
@Override
public void onStartTrackingTouch(SeekBar seekBar) {
// TODO Auto-generated method stub
}
@Override
public void onProgressChanged(SeekBar seekBar, int progress,
boolean fromUser) {
// TODO Auto-generated method stub
}
});
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暂停事件:
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public void pauseEvent(View view) {
if (btn_PauseButton.getText().equals( "继续" )) {
mediaPlayer.start();
btn_PauseButton.setText( "暂停" );
return ;
}
if (mediaPlayer != null && mediaPlayer.isPlaying()) {
mediaPlayer.pause();
btn_PauseButton.setText( "继续" );
}
} |
停止事件:
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public void stopEvent(View view) {
if (mediaPlayer != null && mediaPlayer.isPlaying()) {
btn_PlayButton.setEnabled( true );
mediaPlayer.stop();
// 释放mediaplayer否则的话会占用内存
mediaPlayer.release();
mediaPlayer = null ;
}
btn_PauseButton.setText( "暂停" );
btn_PlayButton.setEnabled( true );
} |
重播事件:
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public void replayEvent(View view) {
surfaceView.setVisibility(View.VISIBLE);
if (mediaPlayer != null && mediaPlayer.isPlaying()) {
mediaPlayer.seekTo( 0 );
} else {
playEvent(view);
}
// 重播的时候应该设置播放的状态
btn_PlayButton.setEnabled( true );
} |