获取选定的索引标签栏控制器Swift

我正在尝试获取tabbarController的选定索引。

let application = UIApplication.sharedApplication().delegate as AppDelegate let tabbarController = application.tabBarController as UITabBarController let selectedIndex = tabBarController.selectedIndex 

我收到这个错误： 'UITabBarController?' does not have a member named 'selectedIndex' 'UITabBarController?' does not have a member named 'selectedIndex'

我错过了什么吗？

Answer 1

application.tabBarController是可选的，这意味着它可以是nil 。 如果您确定永远不会nil ，请执行以下操作：

 var selectedIndex = tabBarController!.selectedIndex 

Answer 2

你应该试试这个：

 let application = UIApplication.shared.delegate as! AppDelegate let tabbarController = application.window?.rootViewController as! UITabBarController let selectedIndex = tabbarController.selectedIndex