I have an app that keeps on listening to voice and converting it to commands using Google Voice API.
I have been using setStreamMute(AudioManager.STREAM_SYSTEM
Mute the beep by muting the notification sound:
(getSystemService(Context.AUDIO_SERVICE) as AudioManager).adjustStreamVolume(AudioManager.STREAM_NOTIFICATION, AudioManager.ADJUST_MUTE,0)
Make sure to unmute it after you start listening:
(getSystemService(Context.AUDIO_SERVICE) as AudioManager).adjustStreamVolume(AudioManager.STREAM_NOTIFICATION, AudioManager.ADJUST_UNMUTE,0)
Please note that there's a beep sound when the listening stops.