Android学习：SeekBar实现音量调节

        Android学习：SeekBar实现音量调节       

2011-11-28 14:42412人阅读评论(0)收藏举报

SeekBar可以通过滑块的位置来标识数值----而且拖动条允许用户拖动滑块来改变值，因此拖动条通常用于对系统的某种数值进行调节，比如调节音量等。

SeekBar允许用户改变拖动条的滑块外观，改变滑块外观通常通过如下属性来指定：       android:thumb: 指定一个Drawable对象，该对象将自定义滑块。

为了让程序能响应拖动条滑块位置的改变，程序可以考虑为它绑定一个OnSeekBarChangeListener监听器。

 

以下是一个使用SeekBar来调节系统音量的实例：

XML代码：

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  1. <SeekBar 
  2.                android:id="@+id/sound" 
  3.                android:layout_width="150px" 
  4.                android:layout_height="10px" 
  5.                android:max="100"  //设置拖动条最大值 
  6.                android:progress="10"   //设置拖动条当前值 
  7.                android:progressDrawable="@layout/seekbar_style"  //拖动条样式 
  8.                android:thumb="@layout/thumb"/>    //滑块样式 

seekbar_style.xml:

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  1. <?xmlversion="1.0"encoding="UTF-8"?>    
  2. <layer-listxmlns:android="http://schemas.android.com/apk/res/android">    
  3.    
  4.     <itemandroid:id="@android:id/background">    
  5.         <shape>    
  6.             <cornersandroid:radius="10dip"/>    
  7.             <gradientandroid:startColor="#ffffffff"   
  8.                 android:centerColor="#ff000000"android:endColor="#ff808A87"   
  9.                 android:centerY="1"android:angle="270"/>    
  10.         </shape>    
  11.     </item>    
  12.    
  13.     <itemandroid:id="@android:id/progress">    
  14.         <clip>    
  15.             <shape>    
  16.                 <cornersandroid:radius="10dip"/>    
  17.                 <gradientandroid:startColor="#ffffffff"   
  18.                     android:centerColor="#ffFFFF00"android:endColor="#ffAABD00"   
  19.                     android:centerY="1"android:angle="270"/>    
  20.             </shape>    
  21.         </clip>    
  22.     </item>    
  23. </layer-list>     

thumb.xml:

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  1. <?xmlversion="1.0"encoding="UTF-8"?>      
  2. <selectorxmlns:android="http://schemas.android.com/apk/res/android">            
  3.     <!-- 按下状态 -->     
  4.     <item        
  5.         android:state_pressed="true"     
  6.         android:drawable="@drawable/thumb_normal"       
  7.         />       
  8.                  
  9.     <!-- 普通无焦点状态 -->     
  10.     <item        
  11.         android:state_focused="false"        
  12.         android:state_pressed="false"      
  13.         android:drawable="@drawable/thumb_normal"   
  14.     />    
  15.    
  16.    
  17. </selector>     

bacon_seekbar.xml:

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  1. <layer-list 
  2.   xmlns:android="http://schemas.android.com/apk/res/android" 
  3. > 
  4.   <item 
  5.     android:id="@+android:id/background" 
  6.     android:drawable="@drawable/thumb_normal"/> 
  7.   <item 
  8.     android:id="@+android:id/SecondaryProgress" 
  9.     android:drawable="@drawable/thumb_normal"/> 
  10.   <item 
  11.     android:id="@+android:id/progress" 
  12.     android:drawable="@drawable/thumb_normal"/> 
  13. </layer-list> 

JAVA代码：

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  1. publicclass PianoActivity extends Activity { 
  2.     /** Called when the activity is first created. */ 
  3.      private ImageButton imageButton_white1; 
  4.     private MediaPlayer mediaPlayer01; 
  5.     public  AudioManager audiomanage; 
  6.     private TextView mVolume ;  //显示当前音量 
  7.      public  SeekBar soundBar; 
  8.      privateint maxVolume, currentVolume;   
  9.  
  10.  
  11.  
  12.     privateint volume=0;  //初始化声音 
  13.  
  14.     @Override 
  15.     publicvoid onCreate(Bundle savedInstanceState) { 
  16.         super.onCreate(savedInstanceState); 
  17.         setContentView(R.layout.main); 
  18.         mediaPlayer01 = new MediaPlayer(); 
  19.        
  20.         
  21.  
  22.         imageButton_white1=(ImageButton)findViewById(R.id.white1); 
  23.         final SeekBar soundBar=(SeekBar)findViewById(R.id.sound);  //音量设置 
  24.         mVolume = (TextView)findViewById(R.id.mVolume);   
  25.         audiomanage = (AudioManager)getSystemService(Context.AUDIO_SERVICE);   
  26.  
  27.  
  28.         maxVolume = audiomanage.getStreamMaxVolume(AudioManager.STREAM_MUSIC);  //获取系统最大音量 
  29.         soundBar.setMax(maxVolume);   //拖动条最高值与系统最大声匹配 
  30.         currentVolume = audiomanage.getStreamVolume(AudioManager.STREAM_MUSIC);  //获取当前值 
  31.         soundBar.setProgress(currentVolume);   
  32.         mVolume.setText(currentVolume*100/maxVolume + " %");   
  33.   
  34.         soundBar.setOnSeekBarChangeListener(new OnSeekBarChangeListener() //调音监听器 
  35.         { 
  36.             publicvoid onProgressChanged(SeekBar arg0,int progress,boolean fromUser) 
  37.             { 
  38.                 audiomanage.setStreamVolume(AudioManager.STREAM_MUSIC, progress, 0);   
  39.                 currentVolume = audiomanage.getStreamVolume(AudioManager.STREAM_MUSIC);  //获取当前值 
  40.                 soundBar.setProgress(currentVolume);   
  41.                 mVolume.setText(currentVolume*100/maxVolume + " %");   
  42.             } 
  43.              
  44.             @Override 
  45.             publicvoid onStartTrackingTouch(SeekBar seekBar) { 
  46.                 // TODO Auto-generated method stub 
  47.                  
  48.             } 
  49.             @Override 
  50.             publicvoid onStopTrackingTouch(SeekBar seekBar) { 
  51.                 // TODO Auto-generated method stub 
  52.                  
  53.  
  54.             } 
  55.         }); 
posted @ 2012-04-10 22:26  慢~慢来  阅读(1165)  评论(0)  编辑  收藏  举报