在做voip通话的过程中，会频繁使用到免提播放和听筒接听的功能，而如何正确的切换，和AudioManager的调度是分不开的，直接上代码：

//获取AudioManager服务

private val audioManager =

AppUtils.getApplication().getSystemService(Context.AUDIO_SERVICE) as AudioManager

/**

* 扬声器切换

* true: 打开

*/

fun setSpeakerPhoneOn(on: Boolean) {

if (on) {

//设置mode

audioManager.mode = AudioManager.MODE_IN_COMMUNICATION

//设置音量，解决有些机型切换后没声音或者声音突然变大的问题

audioManager.setStreamVolume(

AudioManager.STREAM_VOICE_CALL,

audioManager.getStreamVolume(AudioManager.STREAM_VOICE_CALL),

AudioManager.FX_KEY_CLICK

)

//扬声器开启，此方法调用之前需要先设置好mode

audioManager.isSpeakerphoneOn = true

} else {

//5.0以上

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {

//设置mode

audioManager.mode = AudioManager.MODE_IN_COMMUNICATION

//设置音量，解决有些机型切换后没声音或者声音突然变大的问题

audioManager.setStreamVolume(

AudioManager.STREAM_VOICE_CALL,

audioManager.getStreamVolume(AudioManager.STREAM_VOICE_CALL),

AudioManager.FX_KEY_CLICK

)

} else {

//设置mode

audioManager.mode = AudioManager.MODE_IN_CALL

audioManager.setStreamVolume(

AudioManager.STREAM_VOICE_CALL,

audioManager.getStreamVolume(AudioManager.STREAM_VOICE_CALL),

AudioManager.FX_KEY_CLICK

)

}

//扬声器关闭，此方法调用之前需要先设置好mode

audioManager.isSpeakerphoneOn = false

}

}

/**

* 麦克风开关

* RINGER_MODE_SILENT 静音,且无振动

* RINGER_MODE_VIBRATE 静音,但有振动

* RINGER_MODE_NORMAL 正常声音,振动开关由setVibrateSetting决定.

* true:静音

*/

fun setVoiceOn(on: Boolean) {

audioManager.isMicrophoneMute = on

// ToastUtils.shortBottom(if (on) "麦克风已关闭" else "麦克风已启用")

}

/**

* 重设audioManager状态

* 扬声器切换为NORMAL && 打开麦克风

*/

fun resetAudioState() {

//设置mode 为喇叭播放

audioManager.mode = AudioManager.MODE_NORMAL

//设置音量，解决有些机型切换后没声音或者声音突然变大的问题

audioManager.setStreamVolume(

AudioManager.STREAM_MUSIC,

audioManager.getStreamVolume(AudioManager.STREAM_MUSIC),

AudioManager.FX_KEY_CLICK

)

audioManager.isSpeakerphoneOn = true

setVoiceOn(false)

}

方法调用代码如上，下面来分析一下使用中要重点注意的元素：

1.audioManager.mode

AudioManager中给出了如下mode种类，正确的选择mode进行配置，才能提升用户体验；

/**

* Invalid audio mode.

*/

public static final int MODE_INVALID = AudioSystem.MODE_INVALID;

/**

* Current audio mode. Used to apply audio routing to current mode.

*/

public static final int MODE_CURRENT = AudioSystem.MODE_CURRENT;

/**

* Normal audio mode: not ringing and no call established.

*/

public static final int MODE_NORMAL = AudioSystem.MODE_NORMAL;

/**

* Ringing audio mode. An incoming is being signaled.

*/

public static final int MODE_RINGTONE = AudioSystem.MODE_RINGTONE;

/**

* In call audio mode. A telephony call is established.

*/

public static final int MODE_IN_CALL = AudioSystem.MODE_IN_CALL;

/**

* In communication audio mode. An audio/video chat or VoIP call is established.

*/

public static final int MODE_IN_COMMUNICATION = AudioSystem.MODE_IN_COMMUNICATION;

在VOIP场景中，主要就是为了通话服务，所以选择mode的时候，设置为MODE_IN_COMMUNICATION 就比较合适，如果设置为MODE_NORMAL 去开启扬声器，就可能会出现和其他音频播放声音混杂，甚至互相干扰啸叫严重的问题。