获取视图被取消的时刻

I am trying to implement a custom camera on a view that has both the camera and a section for the user to add comment. So far so good, but what I want is to get the moment when this view is dismissed and goes back to the previous view (something like the imagePicker(didFinishPickingImage)) and also pass the taken picture and comment as parameters. I think I should implement a protocol but I have no idea where to start.I am trying to implement a custom camera on a v