Android audioManager解决MediaPlayer AudioTrack 调节音量问题

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

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);               }           }                  }                      }

当然还要添加权限

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