获取最顶级的 UIViewController [英] Get top most UIViewController

问题描述

如果不访问 UINavigationController，我似乎无法获得最高的 UIViewController.这是我目前所拥有的:

I can't seem to get the top most UIViewController without access to a UINavigationController. Here is what I have so far:

UIApplication.sharedApplication().keyWindow?.rootViewController?.presentViewController(vc, animated: true, completion: nil)

然而，它似乎没有做任何事情.keyWindow 和 rootViewController 似乎也是非 nil 值，因此可选链应该不是问题.

However, it does not seem to do anything. The keyWindow and rootViewController seem to be non-nil values too, so the optional chaining shouldn't be an issue.

注意: 做这样的事情是个坏主意.它打破了 MVC 模式.

推荐答案

presentViewController 显示一个视图控制器.它不返回视图控制器.如果您没有使用 UINavigationController，您可能正在寻找 presentedViewController，并且您需要从根开始并向下遍历呈现的视图.>

presentViewController shows a view controller. It doesn't return a view controller. If you're not using a UINavigationController, you're probably looking for presentedViewController and you'll need to start at the root and iterate down through the presented views.

if var topController = UIApplication.sharedApplication().keyWindow?.rootViewController {
    while let presentedViewController = topController.presentedViewController {
        topController = presentedViewController
    }

    // topController should now be your topmost view controller
}

对于 Swift 3+:

For Swift 3+:

if var topController = UIApplication.shared.keyWindow?.rootViewController {
    while let presentedViewController = topController.presentedViewController {
        topController = presentedViewController
    }

    // topController should now be your topmost view controller
}

iOS 13+

let keyWindow = UIApplication.shared.windows.filter {$0.isKeyWindow}.first

if var topController = keyWindow?.rootViewController {
    while let presentedViewController = topController.presentedViewController {
        topController = presentedViewController
    }

// topController should now be your topmost view controller
}

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