本文例項講述了Android使用AudioManager修改系統音量的方法。分享給大家供大家參考，具體如下：

下面介紹幾個AudioManager的幾個音量調整方面的方法.

首先是得到AudioManager例項:

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

調整音量方法有兩種,一種是漸進式,即像手動按音量鍵一樣,一步一步增加或減少,另一種是直接設定音量值.

1、漸進式

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

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

解釋一下三個引數

第一個streamType是需要調整音量的型別,這裡設的是媒體音量,可以是:

STREAM_ALARM 警報

STREAM_MUSIC 音樂回放即媒體音量

STREAM_NOTIFICATION 視窗頂部狀態列Notification,

STREAM_RING 鈴聲

STREAM_SYSTEM 系統

STREAM_VOICE_CALL 通話

STREAM_DTMF 雙音多頻,不是很明白什麼東西

第二個direction,是調整的方向,增加或減少,可以是:

ADJUST_LOWER 降低音量

ADJUST_RAISE 升高音量

ADJUST_SAME 保持不變,這個主要用於向用戶展示當前的音量

第三個flags是一些附加引數,只介紹兩個常用的

FLAG_PLAY_SOUND 調整音量時播放聲音

FLAG_SHOW_UI 調整時顯示音量條,就是按音量鍵出現的那個

2、直接設定音量值的方法:

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);//得到聽筒模式的最大值

am.getStreamVolume(AudioManager.STREAM_VOICE_CALL);//得到聽筒模式的當前值

第一個和第三個引數與上面的相同

第二個引數是一個音量的int值,getStreamMaxVolume(int streamType)得到的是該型別音量的最大值,可以根據這個值計算你需要的音量,我這裡直接調到最大.

最後我的程式碼：

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 播放音訊 如wav格式

* 並允許調節音量

* @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);//設定當前音量大小

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);//音量調節的極限

// soundValue.setProgress(70);//設定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);//設定音量

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);

}

}

}

}

當然還要設定許可權

<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" />