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本文來自http://blog.csdn.net/hellogv/ ，引用必須註明出處！

     以前曾經地介紹過MediaPlayer的基本用法，這裡就深入地講解MediaPlayer的線上播放功能。本文主要實現MediaPlayer線上播放音訊的功能，由於線上視訊播放比線上音訊播放複雜，因此先介紹線上音訊播放的實現，這樣可以幫助大家逐步深入瞭解MediaPlayer的線上播放功能。

先來看看本文程式執行的結果：

main.xml的原始碼如下：

[xhtml] view plain copy print ?

1. <?xml version="1.0" encoding="utf-8"?>  
2. <FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"  
3.     android:layout_height
   ="fill_parent" android:layout_width="fill_parent">  
4.     <LinearLayout android:layout_height="wrap_content"  
5.         android:layout_width="fill_parent" android:orientation="vertical"  
6.         android:layout_gravity="top">  
7.         <LinearLayout android:orientation="horizontal"  
8.             android:layout_gravity="center_horizontal" android:layout_marginTop="4.0dip"  
9.             android:layout_height="wrap_content" android:layout_width="wrap_content">  
10.             <Button android:layout_width="wrap_content"  
11.                 android:layout_height="wrap_content" android:id="@+id/btnPlayUrl"  
12.                 android:text="播放網路音訊"></Button>  
13.             <Button android:layout_height="wrap_content" android:id="@+id/btnPause"  
14.                 android:text="暫停" android:layout_width="80dip"></Button>  
15.             <Button android:layout_height="wrap_content"  
16.                 android:layout_width="80dip" android:text="停止" android:id="@+id/btnStop"></Button>  
17.         </LinearLayout>  
18.         <LinearLayout android:orientation="horizontal"  
19.             android:layout_width="fill_parent" android:layout_height="wrap_content"  
20.             android:layout_marginBottom="20dip">  
21.             <SeekBar android:paddingRight="10dip" android:layout_gravity="center_vertical"  
22.                 android:paddingLeft="10dip" android:layout_weight="1.0"  
23.                 android:layout_height="wrap_content" android:layout_width="wrap_content"  
24.                 android:id="@+id/skbProgress" android:max="100"></SeekBar>  
25.         </LinearLayout>  
26.     </LinearLayout>  
27. </FrameLayout>  

<?xml version="1.0" encoding="utf-8"?><FrameLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_height="fill_parent" android:layout_width="fill_parent"> <LinearLayout android:layout_height="wrap_content"  android:layout_width="fill_parent" android:orientation="vertical"  android:layout_gravity="top">  <LinearLayout android:orientation="horizontal"   android:layout_gravity="center_horizontal" android:layout_marginTop="4.0dip"   android:layout_height="wrap_content" android:layout_width="wrap_content">   <Button android:layout_width="wrap_content"    android:layout_height="wrap_content" android:id="@+id/btnPlayUrl"    android:text="播放網路音訊"></Button>   <Button android:layout_height="wrap_content" android:id="@+id/btnPause"    android:text="暫停" android:layout_width="80dip"></Button>   <Button android:layout_height="wrap_content"    android:layout_width="80dip" android:text="停止" android:id="@+id/btnStop"></Button>  </LinearLayout>  <LinearLayout android:orientation="horizontal"   android:layout_width="fill_parent" android:layout_height="wrap_content"   android:layout_marginBottom="20dip">   <SeekBar android: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實現了“進度條更新”、“資料緩衝”等功能，雖然不是很複雜的功能，但卻是非常有用的功能。Player.java原始碼如下：

[java] view plain copy print ?

1. package com.musicplayer;  
2.   
3.   
4. import java.io.IOException;  
5. import java.util.Timer;  
6. import java.util.TimerTask;  
7. import android.media.AudioManager;  
8. import android.media.MediaPlayer;  
9. import android.media.MediaPlayer.OnBufferingUpdateListener;  
10. import android.media.MediaPlayer.OnCompletionListener;  
11. import android.os.Handler;  
12. import android.os.Message;  
13. import android.util.Log;  
14. import android.widget.SeekBar;  
15.   
16. public class Player implements OnBufferingUpdateListener,  
17.         OnCompletionListener, MediaPlayer.OnPreparedListener{  
18.     public MediaPlayer mediaPlayer;  
19.     private SeekBar skbProgress;  
20.     private Timer mTimer=new Timer();  
21.     public Player(SeekBar skbProgress)  
22.     {  
23.         this.skbProgress=skbProgress;  
24.           
25.         try {  
26.             mediaPlayer = new MediaPlayer();  
27.             mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);  
28.             mediaPlayer.setOnBufferingUpdateListener(this);  
29.             mediaPlayer.setOnPreparedListener(this);  
30.         } catch (Exception e) {  
31.             Log.e("mediaPlayer", "error", e);  
32.         }  
33.           
34.         mTimer.schedule(mTimerTask, 0, 1000);  
35.     }  
36.       
37.     /******************************************************* 
38.      * 通過定時器和Handler來更新進度條 
39.      ******************************************************/  
40.     TimerTask mTimerTask = new TimerTask() {  
41.         @Override  
42.         public void run() {  
43.             if(mediaPlayer==null)  
44.                 return;  
45.             if (mediaPlayer.isPlaying() && skbProgress.isPressed() == false) {  
46.                 handleProgress.sendEmptyMessage(0);  
47.             }  
48.         }  
49.     };  
50.       
51.     Handler handleProgress = new Handler() {  
52.         public void handleMessage(Message msg) {  
53.   
54.             int position = mediaPlayer.getCurrentPosition();  
55.             int duration = mediaPlayer.getDuration();  
56.               
57.             if (duration > 0) {  
58.                 long pos = skbProgress.getMax() * position / duration;  
59.                 skbProgress.setProgress((int) pos);  
60.             }  
61.         };  
62.     };  
63.     //*****************************************************  
64.       
65.     public void play()  
66.     {  
67.         mediaPlayer.start();  
68.     }  
69.       
70.     public void playUrl(String videoUrl)  
71.     {  
72.         try {  
73.             mediaPlayer.reset();  
74.             mediaPlayer.setDataSource(videoUrl);  
75.             mediaPlayer.prepare();//prepare之後自動播放  
76.             //mediaPlayer.start();  
77.         } catch (IllegalArgumentException e) {  
78.             // TODO Auto-generated catch block  
79.             e.printStackTrace();  
80.         } catch (IllegalStateException e) {  
81.             // TODO Auto-generated catch block  
82.             e.printStackTrace();  
83.         } catch (IOException e) {  
84.             // TODO Auto-generated catch block  
85.             e.printStackTrace();  
86.         }  
87.     }  
88.   
89.       
90.     public void pause()  
91.     {  
92.         mediaPlayer.pause();  
93.     }  
94.       
95.     public void stop()  
96.     {  
97.         if (mediaPlayer != null) {   
98.             mediaPlayer.stop();  
99.             mediaPlayer.release();   
100.             mediaPlayer = null;   
101.         }   
102.     }  
103.   
104.     @Override  
105.     /**  
106.      * 通過onPrepared播放  
107.      */  
108.     public void onPrepared(MediaPlayer arg0) {  
109.         arg0.start();  
110.         Log.e("mediaPlayer", "onPrepared");  
111.     }  
112.   
113.     @Override  
114.     public void onCompletion(MediaPlayer arg0) {  
115.         Log.e("mediaPlayer", "onCompletion");  
116.     }  
117.   
118.     @Override  
119.     public void onBufferingUpdate(MediaPlayer arg0, int bufferingProgress) {  
120.         skbProgress.setSecondaryProgress(bufferingProgress);  
121.         int currentProgress=skbProgress.getMax()*mediaPlayer.getCurrentPosition()/mediaPlayer.getDuration();  
122.         Log.e(currentProgress+"% play", bufferingProgress + "% buffer");  
123.     }  
124.   
125. }  

package com.musicplayer;import java.io.IOException;import java.util.Timer;import java.util.TimerTask;import android.media.AudioManager;import android.media.MediaPlayer;import android.media.MediaPlayer.OnBufferingUpdateListener;import android.media.MediaPlayer.OnCompletionListener;import android.os.Handler;import android.os.Message;import android.util.Log;import android.widget.SeekBar;public class Player implements OnBufferingUpdateListener,  OnCompletionListener, MediaPlayer.OnPreparedListener{ public MediaPlayer mediaPlayer; private SeekBar skbProgress; private Timer mTimer=new Timer(); public Player(SeekBar skbProgress) {  this.skbProgress=skbProgress;    try {   mediaPlayer = new MediaPlayer();   mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);   mediaPlayer.setOnBufferingUpdateListener(this);   mediaPlayer.setOnPreparedListener(this);  } catch (Exception e) {   Log.e("mediaPlayer", "error", e);  }    mTimer.schedule(mTimerTask, 0, 1000); }  /*******************************************************  * 通過定時器和Handler來更新進度條  ******************************************************/ TimerTask mTimerTask = new TimerTask() {  @Override  public void run() {   if(mediaPlayer==null)    return;   if (mediaPlayer.isPlaying() && skbProgress.isPressed() == false) {    handleProgress.sendEmptyMessage(0);   }  } };  Handler handleProgress = new Handler() {  public void handleMessage(Message msg) {   int position = mediaPlayer.getCurrentPosition();   int duration = mediaPlayer.getDuration();      if (duration > 0) {    long pos = skbProgress.getMax() * position / duration;    skbProgress.setProgress((int) pos);   }  }; }; //*****************************************************  public void play() {  mediaPlayer.start(); }  public void playUrl(String videoUrl) {  try {   mediaPlayer.reset();   mediaPlayer.setDataSource(videoUrl);   mediaPlayer.prepare();//prepare之後自動播放   //mediaPlayer.start();  } catch (IllegalArgumentException e) {   // TODO Auto-generated catch block   e.printStackTrace();  } catch (IllegalStateException e) {   // TODO Auto-generated catch block   e.printStackTrace();  } catch (IOException e) {   // TODO Auto-generated catch block   e.printStackTrace();  } }  public void pause() {  mediaPlayer.pause(); }  public void stop() {  if (mediaPlayer != null) {    mediaPlayer.stop();            mediaPlayer.release();             mediaPlayer = null;         }  } @Override /**  * 通過onPrepared播放  */ public void onPrepared(MediaPlayer arg0) {  arg0.start();  Log.e("mediaPlayer", "onPrepared"); } @Override public void onCompletion(MediaPlayer arg0) {  Log.e("mediaPlayer", "onCompletion"); } @Override public void onBufferingUpdate(MediaPlayer arg0, int bufferingProgress) {  skbProgress.setSecondaryProgress(bufferingProgress);  int currentProgress=skbProgress.getMax()*mediaPlayer.getCurrentPosition()/mediaPlayer.getDuration();  Log.e(currentProgress+"% play", bufferingProgress + "% buffer"); }}

test_musicplayer.java是主程式，負責呼叫Player類，其中關鍵部分是SeekBarChangeEvent這個SeekBar拖動的事件：SeekBar的Progress是0~SeekBar.getMax()之內的數，而MediaPlayer.seekTo()的引數是0~MediaPlayer.getDuration()之內數，所以MediaPlayer.seekTo()的引數是(progress/seekBar.getMax())*player.mediaPlayer.getDuration()。

test_musicplayer.java原始碼如下：

[java] view plain copy print ?

1. package com.musicplayer;  
2.   
3. import android.app.Activity;  
4. import android.os.Bundle;  
5. import android.view.View;  
6. import android.view.View.OnClickListener;  
7. import android.widget.Button;  
8. import android.widget.SeekBar;  
9.   
10. public class test_musicplayer extends Activity {  
11.     private Button btnPause, btnPlayUrl, btnStop;  
12.     private SeekBar skbProgress;  
13.     private Player player;  
14.   
15.     /** Called when the activity is first created. */  
16.     @Override  
17.     public void onCreate(Bundle savedInstanceState) {  
18.         super.onCreate(savedInstanceState);  
19.         setContentView(R.layout.main);  
20.       
21.         this.setTitle("線上音樂播放---hellogv編寫");  
22.   
23.         btnPlayUrl = (Button) this.findViewById(R.id.btnPlayUrl);  
24.         btnPlayUrl.setOnClickListener(new ClickEvent());  
25.   
26.         btnPause = (Button) this.findViewById(R.id.btnPause);  
27.         btnPause.setOnClickListener(new ClickEvent());  
28.   
29.         btnStop = (Button) this.findViewById(R.id.btnStop);  
30.         btnStop.setOnClickListener(new ClickEvent());  
31.   
32.         skbProgress = (SeekBar) this.findViewById(R.id.skbProgress);  
33.         skbProgress.setOnSeekBarChangeListener(new SeekBarChangeEvent());  
34.         player = new Player(skbProgress);  
35.   
36.     }  
37.   
38.     class ClickEvent implements OnClickListener {  
39.   
40.         @Override  
41.         public void onClick(View arg0) {  
42.             if (arg0 == btnPause) {  
43.                 player.pause();  
44.             } else if (arg0 == btnPlayUrl) {  
45.                 //在百度MP3裡隨便搜尋到的,大家可以試試別的連結  
46.                 String url="http://219.138.125.22/myweb/mp3/CMP3/JH19.MP3";  
47.                 player.playUrl(url);  
48.             } else if (arg0 == btnStop) {  
49.                 player.stop();  
50.             }  
51.         }  
52.     }  
53.   
54.     class SeekBarChangeEvent implements SeekBar.OnSeekBarChangeListener {  
55.         int progress;  
56.   
57.         @Override  
58.         public void onProgressChanged(SeekBar seekBar, int progress,  
59.                 boolean fromUser) {  
60.             // 原本是(progress/seekBar.getMax())*player.mediaPlayer.getDuration()  
61.             this.progress = progress * player.mediaPlayer.getDuration()  
62.                     / seekBar.getMax();  
63.         }  
64.   
65.         @Override  
66.         public void onStartTrackingTouch(SeekBar seekBar) {  
67.   
68.         }  
69.   
70.         @Override  
71.         public void onStopTrackingTouch(SeekBar seekBar) {  
72.             // seekTo()的引數是相對與影片時間的數字，而不是與seekBar.getMax()相對的數字  
73.             player.mediaPlayer.seekTo(progress);  
74.         }  
75.     }  
76.   
77. }  

package com.musicplayer;import android.app.Activity;import android.os.Bundle;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;import android.widget.SeekBar;public class test_musicplayer extends Activity { private Button btnPause, btnPlayUrl, btnStop; private SeekBar skbProgress; private Player player; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) {  super.onCreate(savedInstanceState);  setContentView(R.layout.main);   this.setTitle("線上音樂播放---hellogv編寫");  btnPlayUrl = (Button) this.findViewById(R.id.btnPlayUrl);  btnPlayUrl.setOnClickListener(new ClickEvent());  btnPause = (Button) this.findViewById(R.id.btnPause);  btnPause.setOnClickListener(new ClickEvent());  btnStop = (Button) this.findViewById(R.id.btnStop);  btnStop.setOnClickListener(new ClickEvent());  skbProgress = (SeekBar) this.findViewById(R.id.skbProgress);  skbProgress.setOnSeekBarChangeListener(new SeekBarChangeEvent());  player = new Player(skbProgress); } class ClickEvent implements OnClickListener {  @Override  public void onClick(View arg0) {   if (arg0 == btnPause) {    player.pause();   } else if (arg0 == btnPlayUrl) {    //在百度MP3裡隨便搜尋到的,大家可以試試別的連結    String url="http://219.138.125.22/myweb/mp3/CMP3/JH19.MP3";    player.playUrl(url);   } else if (arg0 == btnStop) {    player.stop();   }  } } class SeekBarChangeEvent implements SeekBar.OnSeekBarChangeListener {  int progress;  @Override  public void onProgressChanged(SeekBar seekBar, int progress,    boolean fromUser) {   // 原本是(progress/seekBar.getMax())*player.mediaPlayer.getDuration()   this.progress = progress * player.mediaPlayer.getDuration()     / seekBar.getMax();  }  @Override  public void onStartTrackingTouch(SeekBar seekBar) {  }  @Override  public void onStopTrackingTouch(SeekBar seekBar) {   // seekTo()的引數是相對與影片時間的數字，而不是與seekBar.getMax()相對的數字   player.mediaPlayer.seekTo(progress);  } }}

           

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