獲取選定的索引tabbar控制器Swift

Question

我想獲取tabbarController的選定索引。

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

我得到這個錯誤：'UITabBarController?' does not have a member named 'selectedIndex'

我缺少的東西？

Answer 1

application.tabBarController是可選的，這意味着它可以是nil。 如果你相信它會永遠nil，這樣做：

var selectedIndex = tabBarController!.selectedIndex 

Answer 2

你應該試試這個：

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