显示tabbar角标

写一个刷新角标数的通用方法

可用于IM消息数或者购物车商品数

func refreshBadgeValue(number:Int){
   for vc in (AppDelegate.shared.tabbar?.viewControllers)!{
        if ((vc as! UINavigationController).topViewController!).isKind(of: MCartViewController.self){
            if number < 100 && number > 0{
                vc.tabBarItem.badgeValue = "\(number)"
            }else if number <= 0{
                vc.tabBarItem.badgeValue = nil
            }else{
                vc.tabBarItem.badgeValue = "99+"
            }
            break
        }
    } 
}