Since sharing audio input behaviour varies depending on Android versions, this answer aims to provide a complete solution based on the docs.
Pre-Android 10
Before Android 10 the input audio stream could only be captured by one
app at a time. If some app was already recording or listening to
audio, your app could create an AudioRecord object, but an error would
be returned when you called AudioRecord.startRecording() and the
recording would not start.
So, you can use this function to check if the mic is used by another app for pre Android 10 versions.
private fun isAnotherAppUsingMic(): Boolean {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) return false
createRecorder().apply {
try {
startRecording()
if (recordingState != AudioRecord.RECORDSTATE_RECORDING) {
return true
}
stop()
return false
} catch (e: IllegalStateException) {
return true
} finally {
release()
}
}
}
private fun createRecorder(): AudioRecord {
return AudioRecord(
MediaRecorder.AudioSource.MIC,
SAMPLE_RATE_HZ,
AudioFormat.CHANNEL_IN_MONO,
AudioFormat.ENCODING_PCM_16BIT,
2 * AudioRecord.getMinBufferSize(
SAMPLE_RATE_HZ,
AudioFormat.CHANNEL_IN_MONO,
AudioFormat.ENCODING_PCM_16BIT
)
)
}
const val SAMPLE_RATE_HZ = 44100
Android 10 and above
Android 10 imposes a priority scheme that can switch the input audio
stream between apps while they are running. In most cases, if a new
app acquires the audio input, the previously capturing app continues
to run, but receives silence.
So, for Android versions 10 and higher, in most cases your app will take priority if there is another app like voice or screen recorder is already running and then you start using mic in your app. But you will need to check for Voice/Video call as it has higher priority and mic won't be available for your app (it will receive silence). You can use below code to check if there is an active call:
private fun isVoiceCallActive(): Boolean {
val audioManager = context.getSystemService(Context.AUDIO_SERVICE) as AudioManager
return audioManager.mode in listOf(
AudioManager.MODE_IN_CALL,
AudioManager.MODE_IN_COMMUNICATION
)
}
In summary you can merge above two function to check if mic is available before you want to use it.
fun isMicAvailable() = !isAnotherAppUsingMic() && !isVoiceCallActive()
