2011.08.15（2）——— android audioManager解决MediaPlayer AudioTrack 调节音量问题

2011.08.15（2）——— android audioManager解决MediaPlayer AudioTrack 调节音量问题

参考：http://www.pocketdigi.com/20110717/398.html

在听筒模式下

am.setSpeakerphoneOn(false);
setVolumeControlStream(AudioManager.STREAM_VOICE_CALL);
am.setMode(AudioManager.MODE_IN_CALL);

我用Mediaplayer AudioTrack调节音量总是失败

at.setStereoVolume(vol, vol);
player.setVolume(vol，vol);

后来 决定用AudioManager来调节音量

AudioManager可以修改系统Android系统的音量
下面介绍几个AudioManager的几个音量调整方面的方法.
首先是得到AudioManager实例:

AudioManager am=(AudioManager)getSystemService(Context.AUDIO_SERVICE);

调整音量方法有两种,一种是渐进式,即像手动按音量键一样,一步一步增加或减少,另一种是直接设置音量值.
1、渐进式

public void adjustStreamVolume (int streamType, int direction, int flags)

am.adjustStreamVolume (AudioManager.STREAM_MUSIC, AudioManager.ADJUST_RAISE, AudioManager.FLAG_SHOW_UI);

解释一下三个参数

第一个streamType是需要调整音量的类型,这里设的是媒体音量,可以是:
STREAM_ALARM 警报
STREAM_MUSIC 音乐回放即媒体音量
STREAM_NOTIFICATION 窗口顶部状态栏Notification,
STREAM_RING 铃声
STREAM_SYSTEM 系统
STREAM_VOICE_CALL 通话
STREAM_DTMF 双音多频,不是很明白什么东西

第二个direction,是调整的方向,增加或减少,可以是:
ADJUST_LOWER 降低音量
ADJUST_RAISE 升高音量
ADJUST_SAME 保持不变,这个主要用于向用户展示当前的音量

第三个flags是一些附加参数,只介绍两个常用的
FLAG_PLAY_SOUND 调整音量时播放声音
FLAG_SHOW_UI 调整时显示音量条,就是按音量键出现的那个
0 表示什么也没有

2、直接设置音量值的方法:

public void setStreamVolume (int streamType, int index, int flags)

am.setStreamVolume(AudioManager.STREAM_MUSIC, am.getStreamMaxVolume(AudioManager.STREAM_MUSIC), AudioManager.FLAG_PLAY_SOUND);
am.getStreamMaxVolume(AudioManager.STREAM_VOICE_CALL);//得到听筒模式的最大值
am.getStreamVolume(AudioManager.STREAM_VOICE_CALL);//得到听筒模式的当前值

第一个和第三个参数与上面的相同
第二个参数是一个音量的int值,getStreamMaxVolume(int streamType)得到的是该类型音量的最大值,可以根据这个值计算你需要的音量,我这里直接调到最大.


最后我的代码：

package com.lp;


import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;

import android.app.Activity;
import android.content.Context;
import android.media.AudioFormat;
import android.media.AudioManager;
import android.media.AudioTrack;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.SeekBar;
/**
 * AudioTrack 播放音频 如wav格式
 * 并允许调节音量
 * @author Administrator
 *
 */
public class MainActivity5 extends Activity {
	private Button play;
	private Button stop;
	private SeekBar soundValue;
	
	private AudioTrack at;
	private AudioManager am;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main_sk);
        am = (AudioManager)getSystemService(Context.AUDIO_SERVICE);
        play = (Button)findViewById(R.id.main_sk_play);
        stop = (Button)findViewById(R.id.main_sk_stop);
        soundValue = (SeekBar)findViewById(R.id.skbVolume);
        setVolumeControlStream(AudioManager.STREAM_VOICE_CALL);
        play.setOnClickListener(new OnClickListener() {
			@Override
			public void onClick(View v) {
				
				if(am.isSpeakerphoneOn()){
					am.setSpeakerphoneOn(false);
				}
				//setVolumeControlStream(AudioManager.STREAM_VOICE_CALL);
				am.setMode(AudioManager.MODE_IN_CALL);
				System.out.println(am.getStreamMaxVolume(AudioManager.STREAM_VOICE_CALL));
				System.out.println("&&&&&&&&&&&&&");
				System.out.println(am.getStreamVolume(AudioManager.STREAM_VOICE_CALL));
				//am.setStreamVolume(streamType, index, flags)
				
				int bufferSizeInBytes = AudioTrack.getMinBufferSize(44100, AudioFormat.CHANNEL_OUT_MONO, AudioFormat.ENCODING_PCM_16BIT);
				
				if(at==null){
					at = new AudioTrack(AudioManager.STREAM_VOICE_CALL, 44100, AudioFormat.CHANNEL_OUT_MONO, AudioFormat.ENCODING_PCM_16BIT, bufferSizeInBytes, AudioTrack.MODE_STREAM);
					System.out.println("22222");
					//at.setStereoVolume(100f, 100f);
					at.setStereoVolume(0.7f, 0.7f);//设置当前音量大小
					new AudioTrackThread().start();
				}else{
					if(at.getPlayState()==AudioTrack.PLAYSTATE_PLAYING){
						System.out.println("111111111");
					}else{
						System.out.println("33333");
						at = new AudioTrack(AudioManager.STREAM_VOICE_CALL, 44100, AudioFormat.CHANNEL_OUT_MONO, AudioFormat.ENCODING_PCM_16BIT, bufferSizeInBytes, AudioTrack.MODE_STREAM);
						new AudioTrackThread().start();
					}
				}
				
			}
        });
        
        stop.setOnClickListener(new OnClickListener() {
			
			@Override
			public void onClick(View v) {
				if(at.getPlayState()==AudioTrack.PLAYSTATE_PLAYING){
					try{
						at.stop();
					}catch (IllegalStateException e)
					{
						e.printStackTrace();
					}
					at.release();
					am.setMode(AudioManager.MODE_NORMAL);
				}
			}   
		});
        
//        soundValue.setMax(100);//音量调节的极限
//        soundValue.setProgress(70);//设置seekbar的位置值
        soundValue.setMax(am.getStreamMaxVolume(AudioManager.STREAM_VOICE_CALL));
        soundValue.setProgress(am.getStreamVolume(AudioManager.STREAM_VOICE_CALL));
		
		soundValue.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
			
			@Override
			public void onStopTrackingTouch(SeekBar seekBar) {
//				float vol=(float)(seekBar.getProgress())/(float)(seekBar.getMax());
//				System.out.println(vol);
//				at.setStereoVolume(vol, vol);//设置音量
				am.setStreamVolume(AudioManager.STREAM_VOICE_CALL, seekBar.getProgress(), AudioManager.FLAG_PLAY_SOUND);
			}
			
			@Override
			public void onStartTrackingTouch(SeekBar seekBar) {
				// TODO Auto-generated method stub
			}
			
			@Override
			public void onProgressChanged(SeekBar seekBar, int progress,
					boolean fromUser) {
				// TODO Auto-generated method stub
			}
		});
    }
    
    class AudioTrackThread extends Thread{  

		@Override
		public void run() {
			byte[] out_bytes = new byte[44100];
			
			InputStream is = getResources().openRawResource(R.raw.start);    
			int length ;
			try{
				at.play();
			}catch (IllegalStateException e)
			{
				e.printStackTrace();
			}
			try {
				while((length = is.read(out_bytes))!=-1){
					//System.out.println(length);
					at.write(out_bytes, 0, length);
				}
			} catch (IOException e) {
				e.printStackTrace();
			}
			if(at.getPlayState()==AudioTrack.PLAYSTATE_PLAYING){
				try{
					at.stop();
				}catch (IllegalStateException e)
				{
					e.printStackTrace();
				}
				at.release();
				am.setMode(AudioManager.MODE_NORMAL);
			}
		}
    	
    }
				
}

当然 权限

<uses-permission android:name="android.permission.MODIFY_AUDIO_SETTINGS" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
 	<uses-permission android:name="android.permission.RECORD_AUDIO" />