UIAppearanceContainer
A protocol that a class must adopt to allow appearance customization using the Uiappearance API.
Declaration
@MainActor protocol UIAppearanceContainer : NSObjectProtocolOverview
To participate in the appearance proxy API, tag appearance property accessor methods in your header with UI_APPEARANCE_SELECTOR.
Appearance property accessor methods must be of the form:
You may have no axes or as many as you like for any property.
The property type may be any standard iOS type: id, NSInteger, NSUInteger, CGFloat, CGPoint, CGSize, CGRect, UIEdgeInsets or UIOffset. Axis parameter values must be either NSInteger or NSUInteger. UIKit throws an exception if other types are used in the axes.
For example, UIBarButtonItem defines these methods: