Appearance Proxies

UIAppearance是一個協(xié)議

@protocol UIAppearance <NSObject>

UIView默認已經(jīng)遵守了這個協(xié)議

@interface UIView : UIResponder <NSCoding, UIAppearance, UIAppearanceContainer, UIDynamicItem, UITraitEnvironment, UICoordinateSpace, UIFocusEnvironment>

來看看UIAppearance都有什么方法

+ (instancetype)appearance;
+ (instancetype)appearanceWhenContainedIn:(nullable Class <UIAppearanceContainer>)ContainerClass, ... NS_REQUIRES_NIL_TERMINATION NS_DEPRECATED_IOS(5_0, 9_0, "Use +appearanceWhenContainedInInstancesOfClasses: instead") __TVOS_PROHIBITED;
+ (instancetype)appearanceWhenContainedInInstancesOfClasses:(NSArray<Class <UIAppearanceContainer>> *)containerTypes NS_AVAILABLE_IOS(9_0);
+ (instancetype)appearanceForTraitCollection:(UITraitCollection *)trait NS_AVAILABLE_IOS(8_0);
+ (instancetype)appearanceForTraitCollection:(UITraitCollection *)trait whenContainedIn:(nullable Class <UIAppearanceContainer>)ContainerClass, ... NS_REQUIRES_NIL_TERMINATION NS_DEPRECATED_IOS(8_0, 9_0, "Use +appearanceForTraitCollection:whenContainedInInstancesOfClasses: instead") __TVOS_PROHIBITED;
+ (instancetype)appearanceForTraitCollection:(UITraitCollection *)trait whenContainedInInstancesOfClasses:(NSArray<Class <UIAppearanceContainer>> *)containerTypes  NS_AVAILABLE_IOS(9_0);

讓某一類控件同時表現(xiàn)某種屬性

[[UIButton appearance] setBackgroundColor:[UIColor blackColor]];
[[UIButton appearance] setTitle:@"呵呵噠" forState:UIControlStateNormal];

讓某一類控件在另一種控件中同時變現(xiàn)某種屬性

[[UIButton appearanceWhenContainedInInstancesOfClasses:@[[UIView class]]] setTitleColor:[UIColor grayColor] forState:UIControlStateNormal];

上面這句話的意思 就是----使UIView上面的UIButton的titleColor都變成灰色的
效果的話大家可以自己試試。