有这个扩展

斯威夫特2。*

extension UIApplication {
    class func topViewController(controller: UIViewController? = UIApplication.sharedApplication().keyWindow?.rootViewController) -> UIViewController? {
        if let navigationController = controller as? UINavigationController {
            return topViewController(navigationController.visibleViewController)
        }
        if let tabController = controller as? UITabBarController {
            if let selected = tabController.selectedViewController {
                return topViewController(selected)
            }
        }
        if let presented = controller?.presentedViewController {
            return topViewController(presented)
        }
        return controller
    }
}

斯威夫特3

extension UIApplication {
    class func topViewController(controller: UIViewController? = UIApplication.shared.keyWindow?.rootViewController) -> UIViewController? {
        if let navigationController = controller as? UINavigationController {
            return topViewController(controller: navigationController.visibleViewController)
        }
        if let tabController = controller as? UITabBarController {
            if let selected = tabController.selectedViewController {
                return topViewController(controller: selected)
            }
        }
        if let presented = controller?.presentedViewController {
            return topViewController(controller: presented)
        }
        return controller
    }
}

然后你可以在控制器的任何地方使用它

if let topController = UIApplication.topViewController() {
    
}

我喜欢@dianz的回答，下面是swift 3的版本。它基本上是一样的，但他少了一个大括号，一些语法/变量/方法名已经改变了。所以它就在这里!

extension UIApplication {
    class func topViewController(base: UIViewController? = UIApplication.shared.keyWindow?.rootViewController) -> UIViewController? {
        if let nav = base as? UINavigationController {
            return topViewController(base: nav.visibleViewController)
        }
        if let tab = base as? UITabBarController {
            if let selected = tab.selectedViewController {
                return topViewController(base: selected)
            }
        }
        if let presented = base?.presentedViewController {
            return topViewController(base: presented)
        }
        return base
    }
}

用法仍然是一样的:

if let topController = UIApplication.topViewController() {
    print("The view controller you're looking at is: \(topController)")
}

基于Dianz的答案，Objective-C版本

- (UIViewController *) topViewController {
   UIViewController *baseVC = UIApplication.sharedApplication.keyWindow.rootViewController;
   if ([baseVC isKindOfClass:[UINavigationController class]]) {
       return ((UINavigationController *)baseVC).visibleViewController;
   }

   if ([baseVC isKindOfClass:[UITabBarController class]]) {
       UIViewController *selectedTVC = ((UITabBarController*)baseVC).selectedViewController;
       if (selectedTVC) {
           return selectedTVC;
       }
   }

   if (baseVC.presentedViewController) {
       return baseVC.presentedViewController;
   }
   return baseVC;
}

试试这个

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

iOS13+ //top最多视图控制器

extension UIViewController {
    func topMostViewController() -> UIViewController {
        if self.presentedViewController == nil {
            return self
        }
        if let navigation = self.presentedViewController as? UINavigationController {
            return navigation.visibleViewController!.topMostViewController()
        }
        if let tab = self.presentedViewController as? UITabBarController {
            if let selectedTab = tab.selectedViewController {
                return selectedTab.topMostViewController()
            }
            return tab.topMostViewController()
        }
        return self.presentedViewController!.topMostViewController()
    }
}

extension UIApplication {
    func topMostViewController() -> UIViewController? {
        return UIWindow.key!.rootViewController?.topMostViewController()
    }
}

extension UIWindow {
    static var key: UIWindow? {
        if #available(iOS 13, *) {
            return UIApplication.shared.windows.first { $0.isKeyWindow }
        } else {
            return UIApplication.shared.keyWindow
        }
    }
}

//use let vc = UIApplication.shared.topMostViewController()

// End top Most view Controller

基于上面的Bob -c:

斯威夫特3.0

extension UIWindow {


    func visibleViewController() -> UIViewController? {
        if let rootViewController: UIViewController  = self.rootViewController {
            return UIWindow.getVisibleViewControllerFrom(vc: rootViewController)
        }
        return nil
    }

    class func getVisibleViewControllerFrom(vc:UIViewController) -> UIViewController {

        if vc.isKind(of: UINavigationController.self) {

            let navigationController = vc as! UINavigationController
            return UIWindow.getVisibleViewControllerFrom( vc: navigationController.visibleViewController!)

        } else if vc.isKind(of: UITabBarController.self) {

            let tabBarController = vc as! UITabBarController
            return UIWindow.getVisibleViewControllerFrom(vc: tabBarController.selectedViewController!)

        } else {

            if let presentedViewController = vc.presentedViewController {

                return UIWindow.getVisibleViewControllerFrom(vc: presentedViewController)

            } else {

                return vc;
            }
        }
    }
}