Android之音量大小

main.xml布局檔案

<?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="播放音樂" />
<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="靜音"
            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="減小音量" 
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" />
</LinearLayout>
</LinearLayout>

AudioActivity類

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; //聲頻
    private AudioManager audioManager=null; //音頻
    
    @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); //設定是否靜音
            }
        });
    }

    View.OnClickListener listener=new View.OnClickListener(){
public void onClick(View v) {
            @SuppressWarnings("unused")
            Button btn=(Button)v;
switch (v.getId()) {
case R.id.btnPlay://播放音樂
                mediaPlayer=MediaPlayer.create(AudioActivity.this, R.raw.music);
                mediaPlayer.setLooping(true);//設定迴圈播放
                mediaPlayer.start();//播放聲音    
                break;
case R.id.btnUpper://增多音量
//adjustStreamVolume: 調整指定聲音類型的音量
                audioManager.adjustStreamVolume(AudioManager.STREAM_MUSIC, 
                        AudioManager.ADJUST_RAISE, 
                        AudioManager.FLAG_SHOW_UI);    //調高聲音
                break;
case R.id.btnLower://減少音量
//第一個參數：聲音類型
//第二個參數：調整音量的方向
//第三個參數：可選的標誌位
                audioManager.adjustStreamVolume(AudioManager.STREAM_MUSIC, 
                        AudioManager.ADJUST_LOWER, 
                        AudioManager.FLAG_SHOW_UI);//調低聲音
                break;
            }
        }
    };

}

運行結果