Android提高第一篇之MediaPlayer

前面写了十四篇关于界面的入门文章，大家都看完和跟着练习之后，对于常用的Layout和View都会有一定的了解了,接下来的文章就不再强调介绍界面了，而是针对具体的常见功能而展开。

        本 文介绍MediaPlayer的使用。MediaPlayer可以播放音频和视频，另外也可以通过VideoView来播放视频，虽然VideoView 比MediaPlayer简单易用，但定制性不如用MediaPlayer，要视情况选择了。MediaPlayer播放音频比较简单，但是要播放视频就 需要SurfaceView。SurfaceView比普通的自定义View更有绘图上的优势，它支持完全的OpenGL ES库。

         先贴出本文程序运行结果的截图，上面是播放/停止音频，可用SeekBar来调进度，下面是播放/停止视频，也是用SeekBar来调进度：

 

main.xml的源码:

 <? xml   version = "1.0"   encoding = "utf-8" ?>
 < LinearLayout   android:id = "@+id/LinearLayout01"
     android:layout_width = "fill_parent"   android:layout_height = "fill_parent"
     xmlns:android = "http://schemas.android.com/apk/res/android"
     android:orientation = "vertical" >
     < SeekBar   android:id = "@+id/SeekBar01"   android:layout_height = "wrap_content"
         android:layout_width = "fill_parent" > </ SeekBar >
     < LinearLayout   android:id = "@+id/LinearLayout02"
         android:layout_width = "wrap_content"   android:layout_height = "wrap_content" >
         < Button   android:id = "@+id/Button01"   android:layout_width = "wrap_content"
             android:layout_height = "wrap_content"   android:text = "播放音频" > </ Button >
         < Button   android:id = "@+id/Button02"   android:layout_width = "wrap_content"
             android:layout_height = "wrap_content"   android:text = "停止播放" > </ Button >
     </ LinearLayout >
     < SeekBar   android:id = "@+id/SeekBar02"   android:layout_height = "wrap_content"
         android:layout_width = "fill_parent" > </ SeekBar >

     < SurfaceView   android:id = "@+id/SurfaceView01"
         android:layout_width = "fill_parent"   android:layout_height = "250px" > </ SurfaceView >
     < LinearLayout   android:id = "@+id/LinearLayout02"
         android:layout_width = "wrap_content"   android:layout_height = "wrap_content" >
         < Button   android:layout_width = "wrap_content"
             android:layout_height = "wrap_content"   android:id = "@+id/Button03"
             android:text = "播放视频" > </ Button >
         < Button   android:layout_width = "wrap_content"
             android:layout_height = "wrap_content"   android:text = "停止播放"   android:id = "@+id/Button04" > </ Button >
     </ LinearLayout >
 </ LinearLayout >

<?xml version="1.0" encoding="utf-8"?> <LinearLayout android:id="@+id/LinearLayout01" android:layout_width="fill_parent" android:layout_height="fill_parent" xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical"> <SeekBar android:id="@+id/SeekBar01" android:layout_height="wrap_content" android:layout_width="fill_parent"></SeekBar> <LinearLayout android:id="@+id/LinearLayout02" android:layout_width="wrap_content" android:layout_height="wrap_content"> <Button android:id="@+id/Button01" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="播放音频"></Button> <Button android:id="@+id/Button02" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="停止播放"></Button> </LinearLayout> <SeekBar android:id="@+id/SeekBar02" android:layout_height="wrap_content" android:layout_width="fill_parent"></SeekBar> <SurfaceView android:id="@+id/SurfaceView01" android:layout_width="fill_parent" android:layout_height="250px"></SurfaceView> <LinearLayout android:id="@+id/LinearLayout02" android:layout_width="wrap_content" android:layout_height="wrap_content"> <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/Button03" android:text="播放视频"></Button> <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="停止播放" android:id="@+id/Button04"></Button> </LinearLayout> </LinearLayout>

 

本文程序的源码，有点长：

 package  com.testMedia;

 import  java.io.IOException;
 import  java.util.Timer;
 import  java.util.TimerTask;
 import  android.app.Activity;
 import  android.media.AudioManager;
 import  android.media.MediaPlayer;
 import  android.os.Bundle;
 import  android.view.SurfaceHolder;
 import  android.view.SurfaceView;
 import  android.view.View;
 import  android.widget.Button;
 import  android.widget.SeekBar;
 import  android.widget.Toast;


 public   class  testMedia  extends  Activity {
       /** Called when the activity is first created. */

     private  SeekBar skb_audio= null ;
     private  Button btn_start_audio =  null ;
     private  Button btn_stop_audio =  null ;

     private  SeekBar skb_video= null ;
     private  Button btn_start_video =  null ;
     private  Button btn_stop_video =  null ;
     private  SurfaceView surfaceView;
     private  SurfaceHolder surfaceHolder;

     private  MediaPlayer m =  null ;
     private  Timer mTimer;
     private  TimerTask mTimerTask;

     private   boolean  isChanging= false ; //互斥变量，防止定时器与SeekBar拖动时进度冲突
      @Override
     public   void  onCreate(Bundle savedInstanceState) {
         super .onCreate(savedInstanceState);
         setContentView(R.layout.main);

         //----------Media控件设置---------//
         m=new  MediaPlayer();

         //播放结束之后弹出提示
         m.setOnCompletionListener(new  MediaPlayer.OnCompletionListener(){
             @Override
             public   void  onCompletion(MediaPlayer arg0) {
                 Toast.makeText(testMedia.this ,  "结束" ,  1000 ).show();
                 m.release();
             }
         });

       //----------定时器记录播放进度---------//
         mTimer = new  Timer();
         mTimerTask = new  TimerTask() {
             @Override
             public   void  run() {
                 if (isChanging== true )
                     return ;

                 if (m.getVideoHeight()== 0 )
                     skb_audio.setProgress(m.getCurrentPosition());
                 else
                     skb_video.setProgress(m.getCurrentPosition());
             }
         };

         mTimer.schedule(mTimerTask, 0 ,  10 );

         btn_start_audio = (Button) this .findViewById(R.id.Button01);
         btn_stop_audio = (Button) this .findViewById(R.id.Button02);
         btn_start_audio.setOnClickListener(new  ClickEvent());
         btn_stop_audio.setOnClickListener(new  ClickEvent());
         skb_audio=(SeekBar)this .findViewById(R.id.SeekBar01);
         skb_audio.setOnSeekBarChangeListener(new  SeekBarChangeEvent());

         btn_start_video = (Button) this .findViewById(R.id.Button03);
         btn_stop_video = (Button) this .findViewById(R.id.Button04);
         btn_start_video.setOnClickListener(new  ClickEvent());
         btn_stop_video.setOnClickListener(new  ClickEvent());
         skb_video=(SeekBar)this .findViewById(R.id.SeekBar02);
         skb_video.setOnSeekBarChangeListener(new  SeekBarChangeEvent());
         surfaceView = (SurfaceView) findViewById(R.id.SurfaceView01);
         surfaceHolder = surfaceView.getHolder();
         surfaceHolder.setFixedSize(100 ,  100 );
         surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
     }

   /*
    * 按键事件处理
    */
   class  ClickEvent  implements  View.OnClickListener{
     @Override
     public   void  onClick(View v) {
         if (v==btn_start_audio)
         {
             m.reset();//恢复到未初始化的状态
             m=MediaPlayer.create(testMedia.this , R.raw.big); //读取音频
             skb_audio.setMax(m.getDuration());//设置SeekBar的长度
             try  {
                 m.prepare();    //准备
             } catch  (IllegalStateException e) {
                 // TODO Auto-generated catch block
                 e.printStackTrace();
             } catch  (IOException e) {
                 // TODO Auto-generated catch block
                 e.printStackTrace();
             }
             m.start();  //播放
         }
         else   if (v==btn_stop_audio || v==btn_stop_video)
         {
             m.stop();
         }
         else   if (v==btn_start_video)
         {
             m.reset();//恢复到未初始化的状态
             m=MediaPlayer.create(testMedia.this , R.raw.test); //读取视频
             skb_video.setMax(m.getDuration());//设置SeekBar的长度
             m.setAudioStreamType(AudioManager.STREAM_MUSIC);
             m.setDisplay(surfaceHolder);//设置屏幕

             try  {
                 m.prepare();

             } 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();
             }
             m.start();
         }
     }
   }

   /*
    * SeekBar进度改变事件
    */
   class  SeekBarChangeEvent  implements  SeekBar.OnSeekBarChangeListener{

     @Override
     public   void  onProgressChanged(SeekBar seekBar,  int  progress,
             boolean  fromUser) {
         // TODO Auto-generated method stub

     }

     @Override
     public   void  onStartTrackingTouch(SeekBar seekBar) {
         isChanging=true ;
     }

     @Override
     public   void  onStopTrackingTouch(SeekBar seekBar) {
         m.seekTo(seekBar.getProgress());
         isChanging=false ;
     }

   }

 }