How to track which application is using the camera?

Question

Android

Recently, I sometimes hear clicks from the phone, sometimes during a call, sometimes when the phone is just in standby mode. Remembering how the camera focused with a click on the nexus 9, I decided to check if it was. I tried to launch the Camera application at that moment and immediately received the phrase, that the Camera cannot be started because the device is currently being used by another application. Are there any ways to determine which application is using the camera?

Answer 1

For example, a list of running applications.