Hands-On Design Patterns with Swift

Removing child view controllers

Once you have added view controllers to a container controller, you may want to remove them if the relationship between those controllers is no longer needed. For example you may want to animate a child view controller through custom transitioning from one view controller to another, and back again. When performing such a transition, you will need to do the following:

• Remove the child controller(s) from their container controller
• Add the child to the next owning controller

When performing the operation on the way back, you will need to perform those steps in the opposite order:

extension UIViewController {    func remove(_ childController: UIViewController,                with animations: (() -> Void)? = nil, duration: TimeInterval? ...