1.
统一设置UITabBarController管理的所有VC的tabBarItem图标文字的颜色大小等属性
. 统一设置UITabBarController管理的所有VC的tabBarItem图标文字的颜色大小等属性 //设置字体大小及颜色(可变字典才可用[]方法设值)
NSMutableDictionary *attr = [NSMutableDictionary dictionary];
attr[NSFontAttributeName] = [UIFont systemFontOfSize:];
attr[NSForegroundColorAttributeName] = [UIColor grayColor]; NSMutableDictionary *selectAttr = [NSMutableDictionary dictionary];
selectAttr[NSFontAttributeName] = [UIFont systemFontOfSize:];//NSFontAttributeName是个const变量，一旦设置了19，后面就不能再改了，这里改为5无效
selectAttr[NSForegroundColorAttributeName] = [UIColor darkGrayColor];//不能写成NSBackgroundColorAttributeName UITabBarItem *item = [UITabBarItem appearance];
[item setTitleTextAttributes:attr forState:UIControlStateNormal];
[item setTitleTextAttributes:selectAttr forState:UIControlStateSelected]; . 就不用像下面这样单独给每一个VC.tabBarItem设置字体大小和颜色了
[vc01.tabBarItem setTitleTextAttributes:attr forState:UIControlStateNormal];
[vc01.tabBarItem setTitleTextAttributes:selectAttr forState:UIControlStateSelected]; [vc02.tabBarItem setTitleTextAttributes:attr forState:UIControlStateNormal];
[vc02.tabBarItem setTitleTextAttributes:selectAttr forState:UIControlStatelectSelected]; [vc03.tabBarItem setTitleTextAttributes:attr forState:UIControlStateNormal];
[vc03.tabBarItem setTitleTextAttributes:selectAttr forState:UIControlStateSelected];
2.
原理是：setTitleTextAttributes:forState: 函数后面有备注UI_APPEARANCE_SELECTOR，
可以通过 [Class appearance] setTitleTextAttributes: forState: ]; 来同一设置字体颜色。
//设置UITabBarItem:UIBarItem的颜色属性 NS_CLASS_AVAILABLE_IOS(2_0) @interface UIBarItem : NSObject <NSCoding, UIAppearance> - (void)setTitleTextAttributes:(nullable NSDictionary<NSString *,id> *)attributes forState:(UIControlState)state NS_AVAILABLE_IOS(5_0) UI_APPEARANCE_SELECTOR; - (nullable NSDictionary<NSString *,id> *)titleTextAttributesForState:(UIControlState)state NS_AVAILABLE_IOS(5_0) UI_APPEARANCE_SELECTOR
3.
封装了如下方法，后续要同一设置根控制器UITabBarController管理的各个VC的tabBarItem的字体和颜色，可直接在UITabBarController的viewDidLoad方法中调用[self setTabBarItemFontAndColor];
//统一设置所有vc的TabBarItem的字体和颜色
- (void)setTabBarItemFontAndColor { //设置字体大小及颜色(可变字典才可用此方法)
NSMutableDictionary *attr = [NSMutableDictionary dictionary];
attr[NSFontAttributeName] = [UIFont systemFontOfSize:];
attr[NSForegroundColorAttributeName] = [UIColor grayColor];//NSBackgroundColorAttributeName字体的背景颜色，一般不需要 NSMutableDictionary *selectAttr = [NSMutableDictionary dictionary];
selectAttr[NSFontAttributeName] = [UIFont systemFontOfSize:];//NSFontAttributeName是个const变量，一旦设置了19，后面就不能再改了，这里改为5无效
selectAttr[NSForegroundColorAttributeName] = [UIColor darkGrayColor];//这里不能写成NSBackgroundColorAttributeName UITabBarItem *item = [UITabBarItem appearance];
[item setTitleTextAttributes:attr forState:UIControlStateNormal];
[item setTitleTextAttributes:selectAttr forState:UIControlStateSelected];//注意此处为UIControlStateSelected,不能写成Highlighted了 //原理是：setTitleTextAttributes:forState: 函数后面有备注UI_APPEARANCE_SELECTOR，可以通过 [Class appearance] setTitleTextAttributes: forState: ]; 来同一设置字体颜色。
}