Android audioManager解决MediaPlayer AudioTrack 调节音量问题.doc

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; 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 byte44100; 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.pri