以下是一个使用SeekBar来调节系统音量的实例：

1、XML：

android:id="@+id/sound"

android:layout_width="150px"

android:layout_height="10px"

android:max="100"

//设置拖动条最大值

android:progress="10"

//设置拖动条当前值

android:progressDrawable="@layout/seekbar_style"

//拖动条样式

android:thumb="@layout/thumb"

/>  //滑块样式

2、seekbar_style.xml:

android:id="@android:id/background">

android:centerColor="#ff000000" android:endColor="#ff808A87"

android:centerY="1" android:angle="270" />

android:id="@android:id/progress">

android:centerColor="#ffFFFF00" android:endColor="#ffAABD00"

android:centerY="1" android:angle="270" />

3、thumb.xml:

version="1.0" encoding="UTF-8"?>

android:state_pressed="true"

android:drawable="@drawable/thumb_normal"

/>

android:state_focused="false"

android:state_pressed="false"

android:drawable="@drawable/thumb_normal"

/>

4、bacon_seekbar.xml:

xmlns:android="http://schemas.android.com/apk/res/android">

android:id="@+android:id/background"

android:drawable="@drawable/thumb_normal"

/>

android:id="@+android:id/SecondaryProgress"

android:drawable="@drawable/thumb_normal"

/>

android:id="@+android:id/progress"

android:drawable="@drawable/thumb_normal"

/>

5、JAVA代码：

public class

PianoActivity extends Activity {

/** Called when the

activity is first created. */

private ImageButton

imageButton_white1;

private MediaPlayer

mediaPlayer01;

public  AudioManager audiomanage;

private

TextView mVolume ;  //显示当前音量

public  SeekBar

soundBar;

private int maxVolume, currentVolume;

private int volume=0;  //初始化声音

@Override

public void

onCreate(Bundle savedInstanceState)

{

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

mediaPlayer01 = new

MediaPlayer();

imageButton_white1=(ImageButton)findViewById(R.id.white1);

final SeekBar soundBar=(SeekBar)findViewById(R.id.sound);

//音量设置

mVolume =

(TextView)findViewById(R.id.mVolume);

audiomanage =

(AudioManager)getSystemService(Context.AUDIO_SERVICE);

maxVolume =

audiomanage.getStreamMaxVolume(AudioManager.STREAM_MUSIC);

//获取系统最大音量

soundBar.setMax(maxVolume);

//拖动条最高值与系统最大声匹配

currentVolume =

audiomanage.getStreamVolume(AudioManager.STREAM_MUSIC);

//获取当前值

soundBar.setProgress(currentVolume);

mVolume.setText(currentVolume*100/maxVolume + " %");

soundBar.setOnSeekBarChangeListener(new

OnSeekBarChangeListener(){调音监听器

public

void onProgressChanged(SeekBar arg0,int progress,boolean

fromUser){

audiomanage.setStreamVolume(AudioManager.STREAM_MUSIC,

progress,

0);

currentVolume

= audiomanage.getStreamVolume(AudioManager.STREAM_MUSIC);

//获取当前值

soundBar.setProgress(currentVolume);

mVolume.setText(currentVolume*100/maxVolume + "

%");

}

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public void onStartTrackingTouch(SeekBar seekBar)

{

// TODO Auto-generated

method

stub

}

@Override

public void onStopTrackingTouch(SeekBar seekBar)

{

// TODO Auto-generated method

stub

}

});

原文：http://www.cnblogs.com/zhangping/p/3514146.html