问题
I want to check the noise level using the android mic. However before accessing the mic I want to know if the mic is being accessed by another application. How do I check if the mic is being accessed by another application?
回答1:
Information about active input streams and where they are routed is held by the AudioFlinger, AudioPolicyManager and AudioHardware instances, which do not share this information with applications.
The AudioManager class provides an isMicrophoneMute() method to applications, but the mic may very well be unmuted while it's unused, so that method doesn't really tell you anything about whether the mic currently is being used or not.
One possible way to find out if there are any input streams routed to the microphone is to do a dumpsys on media.audio_policy and media.audio_flinger and parse the output. But the risk is that the output will look different on different devices, plus I don't know if you're allowed to dump the status of those services on a non-rooted device.
回答2:
I think Michael is right but we can't use dumpsys on Android 2.3 and further for some of the services
来源：https://stackoverflow.com/questions/12018927/check-if-android-mic-is-being-used-by-another-app