Android提高第二十篇之MediaPlayer播放网络音频

本文来自http://blog.csdn.net/hellogv/，引用必须注明出处！

以前曾经地介绍过MediaPlayer的基本用法，这里就深入地讲解MediaPlayer的在线播放功能。本文主要实现MediaPlayer在线播放音频的功能，由于在线视频播放比在线音频播放复杂，因此先介绍在线音频播放的实现，这样可以帮助大家逐步深入了解MediaPlayer的在线播放功能。先来看看本文程序运行的结果：

main.xml的源码如下：

 <?xmlversion="1.0"encoding="utf-8"?>
 <FrameLayoutxmlns:android="http://schemas.android.com/apk/res/android"
 android:layout_height="fill_parent"android:layout_width="fill_parent">
 <LinearLayoutandroid:layout_height="wrap_content"
 android:layout_width="fill_parent"android:orientation="vertical"
 android:layout_gravity="top">
 <LinearLayoutandroid:orientation="horizontal"
 android:layout_gravity="center_horizontal"android:layout_marginTop="4.0dip"
 android:layout_height="wrap_content"android:layout_width="wrap_content">
 <Buttonandroid:layout_width="wrap_content"
 android:layout_height="wrap_content"android:id="@+id/btnPlayUrl"
 android:text="播放网络音频"></Button>
 <Buttonandroid:layout_height="wrap_content"android:id="@+id/btnPause"
 android:text="暂停"android:layout_width="80dip"></Button>
 <Buttonandroid:layout_height="wrap_content"
 android:layout_width="80dip"android:text="停止"android:id="@+id/btnStop"></Button>
 </LinearLayout>
 <LinearLayoutandroid:orientation="horizontal"
 android:layout_width="fill_parent"android:layout_height="wrap_content"
 android:layout_marginBottom="20dip">
 <SeekBarandroid:paddingRight="10dip"android:layout_gravity="center_vertical"
 android:paddingLeft="10dip"android:layout_weight="1.0"
 android:layout_height="wrap_content"android:layout_width="wrap_content"
 android:id="@+id/skbProgress"android:max="100"></SeekBar>
 </LinearLayout>
 </LinearLayout>
 </FrameLayout>

Player.java是本文的核心，Player.java实现了“进度条更新”、“数据缓冲”等功能，虽然不是很复杂的功能，但却是非常有用的功能。Player.java源码如下：

 packagecom.musicplayer;


 importjava.io.IOException;
 importjava.util.Timer;
 importjava.util.TimerTask;
 importandroid.media.AudioManager;
 importandroid.media.MediaPlayer;
 importandroid.media.MediaPlayer.OnBufferingUpdateListener;
 importandroid.media.MediaPlayer.OnCompletionListener;
 importandroid.os.Handler;
 importandroid.os.Message;
 importandroid.util.Log;
 importandroid.widget.SeekBar;

 publicclassPlayerimplementsOnBufferingUpdateListener,
 OnCompletionListener,MediaPlayer.OnPreparedListener{
 publicMediaPlayermediaPlayer;
 privateSeekBarskbProgress;
 privateTimermTimer=newTimer();
 publicPlayer(SeekBarskbProgress)
 {
 this.skbProgress=skbProgress;

 try{
 mediaPlayer=newMediaPlayer();
 mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
 mediaPlayer.setOnBufferingUpdateListener(this);
 mediaPlayer.setOnPreparedListener(this);
 }catch(Exceptione){
 Log.e("mediaPlayer","error",e);
 }

 mTimer.schedule(mTimerTask,0,1000);
 }

 /*******************************************************
 *通过定时器和Handler来更新进度条
 ******************************************************/
 TimerTaskmTimerTask=newTimerTask(){
 @Override
 publicvoidrun(){
 if(mediaPlayer==null)
 return;
 if(mediaPlayer.isPlaying()&&skbProgress.isPressed()==false){
 handleProgress.sendEmptyMessage(0);
 }
 }
 };

 HandlerhandleProgress=newHandler(){
 publicvoidhandleMessage(Messagemsg){

 intposition=mediaPlayer.getCurrentPosition();
 intduration=mediaPlayer.getDuration();

 if(duration>0){
 longpos=skbProgress.getMax()*position/duration;
 skbProgress.setProgress((int)pos);
 }
 };
 };
 //*****************************************************

 publicvoidplay()
 {
 mediaPlayer.start();
 }

 publicvoidplayUrl(StringvideoUrl)
 {
 try{
 mediaPlayer.reset();
 mediaPlayer.setDataSource(videoUrl);
 mediaPlayer.prepare();//prepare之后自动播放
 //mediaPlayer.start();
 }catch(IllegalArgumentExceptione){
 //TODOAuto-generatedcatchblock
 e.printStackTrace();
 }catch(IllegalStateExceptione){
 //TODOAuto-generatedcatchblock
 e.printStackTrace();
 }catch(IOExceptione){
 //TODOAuto-generatedcatchblock
 e.printStackTrace();
 }
 }


 publicvoidpause()
 {
 mediaPlayer.pause();
 }

 publicvoidstop()
 {
 if(mediaPlayer!=null){
 mediaPlayer.stop();
 mediaPlayer.release();
 mediaPlayer=null;
 }
 }

 @Override
 /**
 *通过onPrepared播放
 */
 publicvoidonPrepared(MediaPlayerarg0){
 arg0.start();
 Log.e("mediaPlayer","onPrepared");
 }

 @Override
 publicvoidonCompletion(MediaPlayerarg0){
 Log.e("mediaPlayer","onCompletion");
 }

 @Override
 publicvoidonBufferingUpdate(MediaPlayerarg0,intbufferingProgress){
 skbProgress.setSecondaryProgress(bufferingProgress);
 intcurrentProgress=skbProgress.getMax()*mediaPlayer.getCurrentPosition()/mediaPlayer.getDuration();
 Log.e(currentProgress+"%play",bufferingProgress+"%buffer");
 }

 }

test_musicplayer.java是主程序，负责调用Player类，其中关键部分是SeekBarChangeEvent这个SeekBar拖动的事件：SeekBar的Progress是0~SeekBar.getMax()之内的数，而MediaPlayer.seekTo()的参数是0~MediaPlayer.getDuration()之内数，所以MediaPlayer.seekTo()的参数是(progress/seekBar.getMax())*player.mediaPlayer.getDuration()。

test_musicplayer.java源码如下：

 packagecom.musicplayer;

 importandroid.app.Activity;
 importandroid.os.Bundle;
 importandroid.view.View;
 importandroid.view.View.OnClickListener;
 importandroid.widget.Button;
 importandroid.widget.SeekBar;

 publicclasstest_musicplayerextendsActivity{
 privateButtonbtnPause,btnPlayUrl,btnStop;
 privateSeekBarskbProgress;
 privatePlayerplayer;

 /**Calledwhentheactivityisfirstcreated.*/
 @Override
 publicvoidonCreate(BundlesavedInstanceState){
 super.onCreate(savedInstanceState);
 setContentView(R.layout.main);

 this.setTitle("在线音乐播放---hellogv编写");

 btnPlayUrl=(Button)this.findViewById(R.id.btnPlayUrl);
 btnPlayUrl.setOnClickListener(newClickEvent());

 btnPause=(Button)this.findViewById(R.id.btnPause);
 btnPause.setOnClickListener(newClickEvent());

 btnStop=(Button)this.findViewById(R.id.btnStop);
 btnStop.setOnClickListener(newClickEvent());

 skbProgress=(SeekBar)this.findViewById(R.id.skbProgress);
 skbProgress.setOnSeekBarChangeListener(newSeekBarChangeEvent());
 player=newPlayer(skbProgress);

 }

 classClickEventimplementsOnClickListener{

 @Override
 publicvoidonClick(Viewarg0){
 if(arg0==btnPause){
 player.pause();
 }elseif(arg0==btnPlayUrl){
 //在百度MP3里随便搜索到的,大家可以试试别的链接
 Stringurl="http://219.138.125.22/myweb/mp3/CMP3/JH19.MP3";
 player.playUrl(url);
 }elseif(arg0==btnStop){
 player.stop();
 }
 }
 }

 classSeekBarChangeEventimplementsSeekBar.OnSeekBarChangeListener{
 intprogress;

 @Override
 publicvoidonProgressChanged(SeekBarseekBar,intprogress,
 booleanfromUser){
 //原本是(progress/seekBar.getMax())*player.mediaPlayer.getDuration()
 this.progress=progress*player.mediaPlayer.getDuration()
 /seekBar.getMax();
 }

 @Override
 publicvoidonStartTrackingTouch(SeekBarseekBar){

 }

 @Override
 publicvoidonStopTrackingTouch(SeekBarseekBar){
 //seekTo()的参数是相对与影片时间的数字，而不是与seekBar.getMax()相对的数字
 player.mediaPlayer.seekTo(progress);
 }
 }

 }