Source of view appear calls

ViewControllerWillAppear.swift

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        
        if isMovingToParent {
            print("isMovingToParent")
            // this view controller is becoming visible because it was just push onto a navigation controller or some other container view controller
        } else if isBeingPresented {
            print("isBeingPresented")
            // this view controller is becoming visible because it is being presented from another view controller
        } else if view.window == nil {
            print("view.window == nil ")
            // this view controller is becoming visible for the first time as the window's root view controller
        } else {
            print("else")
            // this view controller is becoming visible because something that was covering it has been dismissed or popped
        }
    }