[转]Appearance

Appearance Proxies

UIAppearance是一个协议，UIView默认已经遵守了这个协议。

@protocol UIAppearance <NSObject>

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

来看看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);

让某一类控件同时表现某种属性

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

让某一类控件在另一种控件中同时变现某种属性

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

上面这句话的意思 就是----使UIView上面的UIButton的titleColor都变成灰色的
效果的话大家可以自己试试，我这里不知道怎么贴图片。。。。。

文／Luxlight（简书作者）
原文链接：http://www.jianshu.com/p/1e4745f0f163
著作权归作者所有，转载请联系作者获得授权，并标注“简书作者”。

自己在模仿 传智微博时的代码

@interface JXTabBarController ()

@end

@implementation JXTabBarController

+ (void)initialize

{

[[UITabBarItem appearanceWhenContainedInInstancesOfClasses:@[[self class]]] setTitleTextAttributes:@{NSForegroundColorAttributeName:[UIColor orangeColor]} forState:UIControlStateSelected];

}