This property defines the view hierarchy of a UIKit.UIView. The complete view hierarchy includes the UIKit.UIView's UIView.Superview and the descendent UIKit.UIViews that are UIView.Subviews of UIView.Subviews, but the methods for manipulating the hierarchy are focused on manipulating subviews (e.g., UIView.AddSubview, UIView.InsertSubview, etc.).

The position of a UIKit.UIView in the UIView.Subviews array determines that UIKit.UIView's z-order among the subviews. The UIKit.UIView at index 0 is the rear-most view. UIKit.UIViews can be initialized in a desired z-order by using UIView.InsertSubviewAbove and UIView.InsertSubviewBelow. UIKit.UIViews can be brought forward or sent backward in z-order by using UIView.ExchangeSubview.

Application developers should not manipulate or modify UIView.Subviews of framework-supplied UIKit.UIViews, as they may change without notice in system updates.