Instance Method

willMove(toParent:)

Called just before the view controller is added or removed from a container view controller.

Declaration

func willMove(toParent parent: UIViewController?)

Parameters

parent

The parent view controller, or nil if there is no parent.

Discussion

Your view controller can override this method when it needs to know that it has been added to a container.

If you are implementing your own container view controller, it must call the willMove(toParent:) method of the child view controller before calling the removeFromParent() method, passing in a parent value of nil.

When your custom container calls the addChild(_:) method, it automatically calls the willMove(toParent:) method of the view controller to be added as a child before adding it.

See Also

Responding to Containment Events

func didMove(toParent: UIViewController?)

Called after the view controller is added or removed from a container view controller.