Type Property

hierarchyInconsistencyException

Raised if the view controller hierarchy is inconsistent with the view hierarchy.

Declaration

class let hierarchyInconsistencyException: NSExceptionName

Discussion

When a view controller'€™s view is added to the view hierarchy, the system walks up the view hierarchy to find the first parent view that has a view controller. That view controller must be the parent of the view controller whose view is being added. Otherwise, this exception is raised. This consistency check is also performed when a view controller is added as a child by calling the addChild(_:) method.

It is also allowed for a view controller that has no parent to add its view to the view hierarchy. This is generally not recommended, but is useful in some special cases.

See Also

Managing Child View Controllers in a Custom Container

var children: [UIViewController]

An array of view controllers that are children of the current view controller.

func addChild(UIViewController)

Adds the specified view controller as a child of the current view controller.

func removeFromParent()

Removes the view controller from its parent.

var shouldAutomaticallyForwardAppearanceMethods: Bool

Returns a Boolean value indicating whether appearance methods are forwarded to child view controllers.

func beginAppearanceTransition(Bool, animated: Bool)

Tells a child controller its appearance is about to change.

func endAppearanceTransition()

Tells a child controller its appearance has changed.

func setOverrideTraitCollection(UITraitCollection?, forChild: UIViewController)

Changes the traits assigned to the specified child view controller.

func overrideTraitCollection(forChild: UIViewController) -> UITraitCollection?

Retrieves the trait collection for a child view controller.