ios 如何获取 UINavigationController 的 rootViewController
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How can I get the rootViewController of UINavigationController
提问by Remsay
I want to get the rootViewController of UINavigationController. It works in Objective-c, but when I use it in Swift , the error reminds me that it was wrong.
我想获取 UINavigationController 的 rootViewController。它在 Objective-c 中工作，但是当我在 Swift 中使用它时，错误提醒我它是错误的。
If I do this, add as! NSArray, it works, but also reminds me that "cast from '[UIViewController]' to unrelated type 'NSArray' always fails".
如果我这样做，添加as! NSArray，它可以工作，但也提醒我“从 '[UIViewController]' 转换为不相关的类型 'NSArray' 总是失败”。
Can somebody show a better way to get the `rootViewController`` without error. Thank you.
有人可以展示一种更好的方法来无错误地获取 `rootViewController`。谢谢你。
回答by user6083088
You can get the root by,
你可以通过，
self.navigationController!.viewControllers.first
回答by Bogdan Farca
Or as an extension:
或者作为扩展：
extension UINavigationController {
var rootViewController : UIViewController? {
return viewControllers.first
}
}
And then you use it like this:
然后你像这样使用它：
if let rootv = navigationController?.rootViewController { }
回答by moonvader
Or maybe this can be used
或者这可以使用
self.navigationController.visibleViewController
or
或者
self.navigationController.topViewController
回答by Sameh Salama
replace
代替
let homevci = controllerArray.objectAtIndex(0) as? NBHomeVC
with
和
let homevci = controllerArray.first as? NBHomeVC
or
或者
let homevci = controllerArray[0] as? NBHomeVC
