这是一个Swift的应用程序的实现与UINavigationController的根。

  if let nav = UIApplication.sharedApplication().keyWindow?.rootViewController as? UINavigationController{
        //get the current's navigation view controller
        var vc = nav.topViewController
        while vc?.presentedViewController != nil {
            vc = vc?.presentedViewController
        }
        return vc
    }

另一个Swift解决方案

func topController() -> UIViewController? {

    // recursive follow
    func follow(from:UIViewController?) -> UIViewController? {
        if let to = (from as? UITabBarController)?.selectedViewController {
            return follow(to)
        } else if let to = (from as? UINavigationController)?.visibleViewController {
            return follow(to)
        } else if let to = from?.presentedViewController {
            return follow(to)
        }
        return from
    }

    let root = UIApplication.sharedApplication().keyWindow?.rootViewController

    return follow(root)

}

斯威夫特5

试试这个

let topVisibleVC = UIApplication.shared.keyWindow?.rootViewController?.visibleViewController

简单的扩展UIApplication在Swift:

注意:

它关心UITabBarController中的moreNavigationController

extension UIApplication {

    class func topViewController(baseViewController: UIViewController? = UIApplication.sharedApplication().keyWindow?.rootViewController) -> UIViewController? {

        if let navigationController = baseViewController as? UINavigationController {
            return topViewController(navigationController.visibleViewController)
        }

        if let tabBarViewController = baseViewController as? UITabBarController {

            let moreNavigationController = tabBarViewController.moreNavigationController

            if let topViewController = moreNavigationController.topViewController where topViewController.view.window != nil {
                return topViewController(topViewController)
            } else if let selectedViewController = tabBarViewController.selectedViewController {
                return topViewController(selectedViewController)
            }
        }

        if let splitViewController = baseViewController as? UISplitViewController where splitViewController.viewControllers.count == 1 {
            return topViewController(splitViewController.viewControllers[0])
        }

        if let presentedViewController = baseViewController?.presentedViewController {
            return topViewController(presentedViewController)
        }

        return baseViewController
    }
}

简单的用法:

if let topViewController = UIApplication.topViewController() {
    //do sth with top view controller
}

这个解决方案是最完整的。它考虑到: UINavigationController UIPageViewController UITabBarController 最上面的视图控制器来自顶部视图控制器

以Swift 3为例。

有3个重载

//Get the topmost view controller for the current application.
public func MGGetTopMostViewController() -> UIViewController?  {

    if let currentWindow:UIWindow = UIApplication.shared.keyWindow {
        return MGGetTopMostViewController(fromWindow: currentWindow)
    }

    return nil
}

//Gets the topmost view controller from a specific window.
public func MGGetTopMostViewController(fromWindow window:UIWindow) -> UIViewController? {

    if let rootViewController:UIViewController = window.rootViewController
    {
        return MGGetTopMostViewController(fromViewController:  rootViewController)
    }

    return nil
}


//Gets the topmost view controller starting from a specific UIViewController
//Pass the rootViewController into this to get the apps top most view controller
public func MGGetTopMostViewController(fromViewController viewController:UIViewController) -> UIViewController {

    //UINavigationController
    if let navigationViewController:UINavigationController = viewController as? UINavigationController {
        let viewControllers:[UIViewController] = navigationViewController.viewControllers
        if navigationViewController.viewControllers.count >= 1 {
            return MGGetTopMostViewController(fromViewController: viewControllers[viewControllers.count - 1])
        }
    }

    //UIPageViewController
    if let pageViewController:UIPageViewController = viewController as? UIPageViewController {
        if let viewControllers:[UIViewController] = pageViewController.viewControllers {
            if viewControllers.count >= 1 {
                return MGGetTopMostViewController(fromViewController: viewControllers[0])
            }
        }
    }

    //UITabViewController
    if let tabBarController:UITabBarController = viewController as? UITabBarController {
        if let selectedViewController:UIViewController = tabBarController.selectedViewController {
            return MGGetTopMostViewController(fromViewController: selectedViewController)
        }
    }

    //Lastly, Attempt to get the topmost presented view controller
    var presentedViewController:UIViewController! = viewController.presentedViewController
    var nextPresentedViewController:UIViewController! = presentedViewController?.presentedViewController

    //If there is a presented view controller, get the top most prensentedViewController and return it.
    if presentedViewController != nil {
        while nextPresentedViewController != nil {

            //Set the presented view controller as the next one.
            presentedViewController = nextPresentedViewController

            //Attempt to get the next presented view controller
            nextPresentedViewController = presentedViewController.presentedViewController
        }
        return presentedViewController
    }

    //If there is no topmost presented view controller, return the view controller itself.
    return viewController
}

以下是对我有效的方法。

我发现有时候控制器在键窗口上是nil，因为键窗口是一些操作系统的东西，如警报等。

 + (UIViewController*)topMostController
 {
     UIWindow *topWndow = [UIApplication sharedApplication].keyWindow;
     UIViewController *topController = topWndow.rootViewController;

     if (topController == nil)
     {
         // The windows in the array are ordered from back to front by window level; thus,
         // the last window in the array is on top of all other app windows.
         for (UIWindow *aWndow in [[UIApplication sharedApplication].windows reverseObjectEnumerator])
         {
             topController = aWndow.rootViewController;
             if (topController)
                 break;
         }
     }

     while (topController.presentedViewController) {
         topController = topController.presentedViewController;
     }

     return topController;
 }