Android通过音量键调节音量大小

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通过程序实现对android系统手机音量的调节

1、获得系统服务

AudioManager(音频管理器)了，该类位于Android.Media包下，提供了音量控制与铃声模式相关操作！使用Context.getSystemService(Context.AUDIO.SERVICE)获得类的实例

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

2、获得音量按键的响应

@Overridepublic boolean onKeyDown(int keyCode, KeyEvent event) {    AudioManager mAudioManager = (AudioManager) getSystemService(Context.AUDIO_SERVICE);    switch (keyCode) {        case KeyEvent.KEYCODE_VOLUME_DOWN:

//对应音量-操作            return true;        case KeyEvent.KEYCODE_VOLUME_UP://对应音量+操作

            return true;        default:            break;    }    return super.onKeyDown(keyCode, event);}

3、音量控制

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1、渐进式控制

public void adjustStreamVolume(int streamType, int direction, int flags) {...}

参数1：streamType需要调整音量的类型,这里设的是媒体音量。有如下类型

/** The audio stream for phone calls */public static final int STREAM_VOICE_CALL = AudioSystem.STREAM_VOICE_CALL;/** The audio stream for system sounds */public static final int STREAM_SYSTEM = AudioSystem.STREAM_SYSTEM;/** The audio stream for the phone ring */public static final int STREAM_RING = AudioSystem.STREAM_RING;/** The audio stream for music playback */public static final int STREAM_MUSIC = AudioSystem.STREAM_MUSIC;/** The audio stream for alarms */public static final int STREAM_ALARM = AudioSystem.STREAM_ALARM;/** The audio stream for notifications */public static final int STREAM_NOTIFICATION = AudioSystem.STREAM_NOTIFICATION;/** @hide The audio stream for phone calls when connected to bluetooth */public static final int STREAM_BLUETOOTH_SCO = AudioSystem.STREAM_BLUETOOTH_SCO;/** @hide The audio stream for enforced system sounds in certain countries (e.g camera in Japan) */public static final int STREAM_SYSTEM_ENFORCED = AudioSystem.STREAM_SYSTEM_ENFORCED;/** The audio stream for DTMF Tones */public static final int STREAM_DTMF = AudioSystem.STREAM_DTMF;/** @hide The audio stream for text to speech (TTS) */public static final int STREAM_TTS = AudioSystem.STREAM_TTS;

参数2：direction是调整的方向,增加或减少。

AudioManager.ADJUST_RAISE,

AudioManager.ADJUST_LOWER,

参数3：flags是一些附加参数,只介绍两个常用的

public static final int FLAG_PLAY_SOUND = 1 << 2; //调整音量时播放声音

public static final int FLAG_SHOW_UI = 1 << 0;//调整音量是显示UI

    mAudioManager.adjustStreamVolume(            AudioManager.STREAM_MUSIC,            AudioManager.ADJUST_RAISE,            AudioManager.FLAG_PLAY_SOUND | AudioManager.FLAG_SHOW_UI);

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2、直接设置音量

获取音量的最大值和当前值，通过算法设置响应的音量

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

参数1和参数3的等同于上一节中的参数，参数2就是你想设置的音量值

int max,current;

max = mAudioManager.getStreamMaxVolume( AudioManager.STREAM_MUSIC );//获得最大值current = mAudioManager.getStreamVolume( AudioManager.STREAM_MUSIC );//获得当前值

4、对应代码

//渐进式@Overridepublic boolean onKeyDown(int keyCode, KeyEvent event) {    AudioManager mAudioManager = (AudioManager) getSystemService(Context.AUDIO_SERVICE);    switch (keyCode) {        case KeyEvent.KEYCODE_VOLUME_DOWN:            mAudioManager.adjustStreamVolume(                    AudioManager.STREAM_MUSIC,                    AudioManager.ADJUST_LOWER,                    AudioManager.FLAG_PLAY_SOUND | AudioManager.FLAG_SHOW_UI);            return true;        case KeyEvent.KEYCODE_VOLUME_UP:            mAudioManager.adjustStreamVolume(                    AudioManager.STREAM_MUSIC,                    AudioManager.ADJUST_RAISE,                    AudioManager.FLAG_PLAY_SOUND | AudioManager.FLAG_SHOW_UI);            return true;        default:            break;    }    return super.onKeyDown(keyCode, event);}

//直接设置@Overridepublic boolean onKeyDown(int keyCode, KeyEvent event) {    int max,current,volume;    AudioManager mAudioManager = (AudioManager) getSystemService(Context.AUDIO_SERVICE);    max = mAudioManager.getStreamMaxVolume( AudioManager.STREAM_MUSIC );    volume = mAudioManager.getStreamVolume( AudioManager.STREAM_MUSIC );    switch (keyCode) {        case KeyEvent.KEYCODE_VOLUME_UP:            if(volume < max)                volume++;            mAudioManager.setStreamVolume (                    AudioManager.STREAM_MUSIC,                    volume,                    AudioManager.FLAG_PLAY_SOUND | AudioManager.FLAG_SHOW_UI);            return true;        case KeyEvent.KEYCODE_VOLUME_DOWN:            if(volume > 0)                volume--;            mAudioManager.setStreamVolume (                    AudioManager.STREAM_MUSIC,                    volume,                    AudioManager.FLAG_PLAY_SOUND | AudioManager.FLAG_SHOW_UI);            return true;        default:            break;    }    return super.onKeyDown(keyCode, event);}

+++参考很多的资料，如有雷同请发邮件给我！^-^+++

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