Android之音量调剂

Android之音量调节
main.xml布局文件

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;            }        }    };    }