Android之音量调节

main.xml布局文件

              <?        xml version        =        "        1.0        "         encoding        =        "        utf-8        "        ?>        
        <        LinearLayout xmlns:android        =        "        http://schemas.android.com/apk/res/android        "        
 android:orientation        =        "        vertical        "         android:layout_width        =        "        fill_parent        "        
 android:layout_height        =        "        fill_parent        "        >        
         <        Button android:id        =        "        @+id/btnPlay        "         
 android:layout_width        =        "        fill_parent        "        
 android:layout_height        =        "        wrap_content        "         
 android:text        =        "        播放音乐        "                 />        
         <        LinearLayout android:orientation        =        "        horizontal        "        
 android:layout_width        =        "        wrap_content        "        
 android:layout_height        =        "        wrap_content        "        
 android:layout_gravity        =        "        center_horizontal        "        >        
         <        ToggleButton android:id        =        "        @+id/tbMute        "        
 android:layout_width        =        "        fill_parent        "        
 android:layout_height        =        "        wrap_content        "         
 android:textOn        =        "        静音        "        
 android:textOff        =        "        正常        "        
 android:checked        =        "        true        "        
 android:layout_gravity        =        "        center_vertical        "                 />        
         <        Button android:id        =        "        @+id/btnUpper        "        
 android:text        =        "        增大音量        "         
 android:layout_width        =        "        wrap_content        "        
 android:layout_height        =        "        wrap_content        "                 />        
         <        Button android:id        =        "        @+id/btnLower        "        
 android:text        =        "        减小音量        "         
 android:layout_width        =        "        wrap_content        "        
 android:layout_height        =        "        wrap_content        "                 />        
         </        LinearLayout        >        
        </        LinearLayout        >

AudioActivity类

              package         com.ljq.activity;

        import         android.app.Activity;
        import         android.app.Service;
        import         android.media.AudioManager;
        import         android.media.MediaPlayer;
        import         android.os.Bundle;
        import         android.view.View;
        import         android.widget.Button;
        import         android.widget.CompoundButton;
        import         android.widget.ToggleButton;
        import         android.widget.CompoundButton.OnCheckedChangeListener;

        public                 class         AudioActivity         extends         Activity {
         private         Button btnPlay        =        null        , btnUpper        =        null        , btnLower        =        null        ;
         private         ToggleButton tbMute        =        null        ;
         private         MediaPlayer mediaPlayer        =        null        ;         //        声频        
                 private         AudioManager audioManager        =        null        ;         //        音频        
         
 @Override
         public                 void         onCreate(Bundle savedInstanceState) {
         super        .onCreate(savedInstanceState);
 setContentView(R.layout.main);
 
 audioManager        =        (AudioManager)getSystemService(Service.AUDIO_SERVICE);
 btnPlay        =        (Button)findViewById(R.id.btnPlay);
 btnUpper        =        (Button)findViewById(R.id.btnUpper);
 btnLower        =        (Button)findViewById(R.id.btnLower);
 btnPlay.setOnClickListener(listener);
 btnUpper.setOnClickListener(listener);
 btnLower.setOnClickListener(listener);
 tbMute        =        (ToggleButton)findViewById(R.id.tbMute);
 tbMute.setOnCheckedChangeListener(        new         OnCheckedChangeListener(){
         public                 void         onCheckedChanged(CompoundButton buttonView,         boolean         isChecked) {
 audioManager.setStreamMute(AudioManager.STREAM_MUSIC,         !        isChecked);         //        设置是否静音        
         }
 });
 }
 
 View.OnClickListener listener        =        new         View.OnClickListener(){
         public                 void         onClick(View v) {
 @SuppressWarnings(        "        unused        "        )
 Button btn        =        (Button)v;
         switch         (v.getId()) {
         case         R.id.btnPlay:        //        播放音乐        
         mediaPlayer        =        MediaPlayer.create(AudioActivity.        this        , R.raw.music);
 mediaPlayer.setLooping(        true        );        //        设置循环播放        
         mediaPlayer.start();        //        播放声音         
                 break        ;
         case         R.id.btnUpper:        //        增多音量
         //        adjustStreamVolume: 调整指定声音类型的音量        
         audioManager.adjustStreamVolume(AudioManager.STREAM_MUSIC, 
 AudioManager.ADJUST_RAISE, 
 AudioManager.FLAG_SHOW_UI);         //        调高声音        
                 break        ;
         case         R.id.btnLower:        //        减少音量
         //        第一个参数：声音类型
         //        第二个参数：调整音量的方向
         //        第三个参数：可选的标志位        
         audioManager.adjustStreamVolume(AudioManager.STREAM_MUSIC, 
 AudioManager.ADJUST_LOWER, 
 AudioManager.FLAG_SHOW_UI);        //        调低声音        
                 break        ;
 }
 }
 };
 
}

运行结果

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