Xcode 7.2.1 Swift 2.1.1

您只需要为所需的UITabBarItem设置badgeValue，如下所示：

tabBarController?.tabBar.items?[4].badgeValue = "1"   // this will add "1" badge to your fifth tab bar item


// or like this to apply it to your first tab
tabBarController?.tabBar.items?.first?.badgeValue = "1st"

// or to apply to your second tab
tabBarController?.tabBar.items?[1].badgeValue = "2nd"

// to apply it to your last tab
tabBarController?.tabBar.items?.last?.badgeValue = "Last"

要从UITabBarItem中删除徽章，只需为其添加nil值

tabBarController?.tabBar.items?.first?.badgeValue = nil