Android之音量调节

main.xml布局文件

    android:orientation="vertical" android:layout_
    android:layout_>
            android:layout_
        android:layout_ 
        android:text="播放音乐" />
            android:layout_
        android:layout_
        android:layout_gravity="center_horizontal">
                    android:layout_
            android:layout_ 
            android:texton="静音"
            android:textoff="正常"
            android:checked="true"
            android:layout_gravity="center_vertical" />
                    android:text="增大音量" 
            android:layout_
            android:layout_ />
                    android:text="减小音量" 
            android:layout_
            android:layout_ />
    

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