change volume

change volume

private var audioManager: AudioManager? = null
audioManager = getSystemService(Context.AUDIO_SERVICE) as AudioManager

override fun onKeyDown(keyCode: Int, event: KeyEvent?): Boolean {
    when (keyCode) {
        KeyEvent.KEYCODE_BACK -> {
           
        }
        KeyEvent.KEYCODE_VOLUME_DOWN -> {
            audioManager?.adjustStreamVolume(AudioManager.STREAM_MUSIC, AudioManager.ADJUST_LOWER, AudioManager.FLAG_SHOW_UI)
            return true
        }
        KeyEvent.KEYCODE_VOLUME_UP -> {
            audioManager?.adjustStreamVolume(AudioManager.STREAM_MUSIC, AudioManager.ADJUST_RAISE, AudioManager.FLAG_SHOW_UI)
            return true
        }
    }
    return super.onKeyDown(keyCode, event)
}