Android实现监听音量的变化
本文实例为大家分享了Android实现监听音量变化的具体代码,供大家参考,具体内容如下
最近项目中涉及到了音量监听然后作出改变的需求,特此mark一下
想监听音量的变化通用的就两种方法:
1、监听音量键的变化
方法: 重写 activity onKeyDown函数
@Override public boolean onKeyDown(int keyCode, KeyEvent event) { switch (keyCode) { case KeyEvent.KEYCODE_VOLUME_UP: //音量键up return false; case KeyEvent.KEYCODE_VOLUME_DOWN: //音量键down return false; default: break; } return super.onKeyDown(keyCode, event); }
优点: 快速,方便,简单
缺点:
1. 容易消耗音量键改变事件(返回false有时也没用),实测
2. 该监听针对当前Activity,不同的Ac要重新重写onKeyDown函数
3. 由第二点可知,无法做到整个应用范围监听
2、获取音量变化的广播
系统音量变化的时候会发送广播,监听这个就行,音量变化的action是
android.media.VOLUME_CHANGED_ACTION
具体的见代码:(kotlin版本)
class VolumeChangeHelper(var context: Context){ private var mVolumeBroadCastReceiver: VolumeBroadCastReceiver? = null private var mVolumeChangeListener: VolumeChangeListener? = null companion object{ const val VOLUME_CHANGE_ACTION = "android.media.VOLUME_CHANGED_ACTION" const val EXTRA_VOLUME_STREAM_TYPE = "android.media.EXTRA_VOLUME_STREAM_TYPE" } private var audioManager: AudioManager? = context.getSystemService(Context.AUDIO_SERVICE) as? AudioManager fun registerVolumeChangeListener(volumeChangeListener: VolumeChangeListener){ mVolumeChangeListener = volumeChangeListener mVolumeBroadCastReceiver = VolumeBroadCastReceiver() val filter = IntentFilter() filter.addAction(VOLUME_CHANGE_ACTION) if(mVolumeBroadCastReceiver != null){ //注册这个广播 context.registerReceiver(mVolumeBroadCastReceiver!!, filter) } } fun unregisterReceiver(){ if(mVolumeBroadCastReceiver != null){ context.unregisterReceiver(mVolumeBroadCastReceiver!!) mVolumeBroadCastReceiver = null } } interface VolumeChangeListener{ fun onVolumeDownToMin() fun onVolumeUp() } //定义一个想监听音量变化的广播接受者 inner class VolumeBroadCastReceiver : BroadcastReceiver(){ override fun onReceive(context: Context?, intent: Intent?) { if(intent?.action == VOLUME_CHANGE_ACTION && intent?.getIntExtra(EXTRA_VOLUME_STREAM_TYPE, -1) == AudioManager.STREAM_MUSIC){ val currentVolume = audioManager?.getStreamVolume(AudioManager.STREAM_MUSIC) ?: -1 if(currentVolume > 0){ mVolumeChangeListener?.onVolumeUp() } else if( currentVolume == 0){ mVolumeChangeListener?.onVolumeDownToMin() } } } } }
想实现全局监听的话,可以在在一个app生命周期内都存在的Context里去监听,比如MainActivity
以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持我们。
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