Instance Method


Tells a child controller its appearance is about to change.


- (void)beginAppearanceTransition:(BOOL)isAppearing animated:(BOOL)animated;



YES if the child view controller'€™s view is about to be added to the view hierarchy, NO if it is being removed.


If YES, the transition is being animated.


If you are implementing a custom container controller, use this method to tell the child that its views are about to appear or disappear. Do not invoke viewWillAppear:, viewWillDisappear:, viewDidAppear:, or viewDidDisappear: directly.

See Also

Managing Child View Controllers in a Custom Container


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

- addChildViewController:

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

- removeFromParentViewController

Removes the view controller from its parent.

- transitionFromViewController:toViewController:duration:options:animations:completion:

Transitions between two of the view controller'€™s child view controllers.


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

- endAppearanceTransition

Tells a child controller its appearance has changed.

- setOverrideTraitCollection:forChildViewController:

Changes the traits assigned to the specified child view controller.

- overrideTraitCollectionForChildViewController:

Retrieves the trait collection for a child view controller.


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