What is the capture button element id in the view finder of the camera in selendroid. I am not able to inspect it

I want to know what is the capture button element id in the view finder of the camera in selendroid. I am not able to inspect it. How to inspect the system apps. Here I am invoking the camera native app through my application to store the photo. But I am not able to inspect and get the element ID of the camera capture button. Please help