IOS 杂笔－13（appearance的巧妙使用）

NSDictionary * attrs = @{
                             
                             NSFontAttributeName:[UIFont systemFontOfSize:13],
                             NSForegroundColorAttributeName:[UIColor grayColor]
                             
                             };
    
    NSDictionary * selectAttrs = @{
                                   
                                   NSFontAttributeName:[UIFont systemFontOfSize:12],
                                   NSForegroundColorAttributeName:[UIColor darkGrayColor]
                                   
                                   };
    
    UITabBarItem * item = [UITabBarItem appearance];
    [item setTitleTextAttributes:attrs forState:UIControlStateNormal];
    [item setTitleTextAttributes:selectAttrs forState:UIControlStateSelected];