Question

如果无法访问UIViewController，我似乎无法获得最高UINavigationController。以下是我到目前为止的情况：

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似乎也是非零值，因此可选链接应该不是问题。

注意： 做这样的事情是个坏主意。它破坏了MVC模式。

Answer 1

有此扩展程序

Swift 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
    }
}

Swift 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
    }
}

您可以在控制器的任何位置使用它

if let topController = UIApplication.topViewController() {

}

Answer 2

presentViewController显示了一个视图控制器。它不会返回视图控制器。如果您没有使用UINavigationController，那么您可能正在寻找presentedViewController，并且您需要从根开始并向下遍历所呈现的视图。

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 +：

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

    // topController should now be your topmost view controller
}

Answer 3

快速4/5 +获取最顶级的viewController

// MARK: UIApplication extensions

extension UIApplication {

    class func getTopViewController(base: UIViewController? = UIApplication.shared.keyWindow?.rootViewController) -> UIViewController? {

        if let nav = base as? UINavigationController {
            return getTopViewController(base: nav.visibleViewController)

        } else if let tab = base as? UITabBarController, let selected = tab.selectedViewController {
            return getTopViewController(base: selected)

        } else if let presented = base?.presentedViewController {
            return getTopViewController(base: presented)
        }
        return base
    }
}

如何使用

if let topVC = UIApplication.getTopViewController() {
   topVC.view.addSubview(forgotPwdView)
}

Answer 4

extension UIWindow {

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

    static func getVisibleViewControllerFrom(vc:UIViewController) -> UIViewController {
        if let navigationController = vc as? UINavigationController,
            let visibleController = navigationController.visibleViewController  {
            return UIWindow.getVisibleViewControllerFrom( vc: visibleController )
        } else if let tabBarController = vc as? UITabBarController,
            let selectedTabController = tabBarController.selectedViewController {
            return UIWindow.getVisibleViewControllerFrom(vc: selectedTabController )
        } else {
            if let presentedViewController = vc.presentedViewController {
                return UIWindow.getVisibleViewControllerFrom(vc: presentedViewController)
            } else {
                return vc
            }
        }
    }
}

用法：

if let topController = window.visibleViewController() {
    println(topController)
}

Answer 5

基于Dianz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;
}

Answer 6

我喜欢@dianz's answer，所以这里是它的快速3版本。它基本上是相同的，但他缺少大括号，一些语法/变量/方法名称已经改变。所以这就是它！

ster = "*"
space = " "
lines = 0
n = 3
x = 1
while lines <= 5:
    print space*n, ster*x
    n-= 1
    x+= 1
    lines += 1

但用法仍然完全相同：

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
    }
}

Answer 7

使用此代码查找最顶层的UIViewController

func getTopViewController() -> UIViewController? {
    var topController: UIViewController? = UIApplication.shared.keyWindow?.rootViewController
    while topController?.presentedViewController != nil {
        topController = topController?.presentedViewController
    }
    return topController
}

Answer 8

https://gist.github.com/db0company/369bfa43cb84b145dfd8 我对该站点的答案和评论进行了一些测试。对我来说，以下作品

extension UIViewController {
    func topMostViewController() -> UIViewController {

        if let presented = self.presentedViewController {
            return presented.topMostViewController()
        }

        if let navigation = self as? UINavigationController {
            return navigation.visibleViewController?.topMostViewController() ?? navigation
        }

        if let tab = self as? UITabBarController {
            return tab.selectedViewController?.topMostViewController() ?? tab
    }

        return self
    }
}

extension UIApplication {
    func topMostViewController() -> UIViewController? {
        return self.keyWindow?.rootViewController?.topMostViewController()
    }
}

然后，通过以下方式获取顶部的viewController：

UIApplication.shared.topMostViewController()

Answer 9

使用计算变量而不是函数对@AlberZou进行细微变化

extension UIViewController {
  var topMostViewController : UIViewController {

    if let presented = self.presentedViewController {
      return presented.topMostViewController
    }

    if let navigation = self as? UINavigationController {
      return navigation.visibleViewController?.topMostViewController ?? navigation
    }

    if let tab = self as? UITabBarController {
      return tab.selectedViewController?.topMostViewController ?? tab
    }

    return self
  }
}

extension UIApplication {
  var topMostViewController : UIViewController? {
    return self.keyWindow?.rootViewController?.topMostViewController
  }
}

然后说

if let topViewControler = UIApplication.shared.topMostViewController {
    ... do stuff
}

Answer 10

基于上面的Bob -c：

Swift 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;
            }
        }
    }
}

Answer 11

import UIKit

extension UIApplication {

    // MARK: Choose keyWindow as per your choice
    var currentWindow: UIWindow? {
        connectedScenes
        .filter({$0.activationState == .foregroundActive})
        .map({$0 as? UIWindowScene})
        .compactMap({$0})
        .first?.windows
        .filter({$0.isKeyWindow}).first
    }

    // MARK: Choose keyWindow as per your choice
    var keyWindow: UIWindow? {
        UIApplication.shared.windows.first { $0.isKeyWindow }
    }

    class func topMostViewController(base: UIViewController? = UIApplication.shared.currentWindow?.rootViewController) -> UIViewController? {

        if let nav = base as? UINavigationController {
            return topMostViewController(base: nav.visibleViewController)
        }

        if let tab = base as? UITabBarController {
            let moreNavigationController = tab.moreNavigationController

            if let top = moreNavigationController.topViewController, top.view.window != nil {
                return topMostViewController(base: top)
            } else if let selected = tab.selectedViewController {
                return topMostViewController(base: selected)
            }
        }
        if let presented = base?.presentedViewController {
            return topMostViewController(base: presented)
        }
        return base
    }
}

Answer 12

对于 Swift 5 + ， iOS 13 +

extension UIViewController {
    static func topMostViewController() -> UIViewController? {
        if #available(iOS 13.0, *) {
            let keyWindow = UIApplication.shared.windows.filter {$0.isKeyWindow}.first
            return keyWindow?.rootViewController?.topMostViewController()
        }
        
        return UIApplication.shared.keyWindow?.rootViewController?.topMostViewController()
    }
    
    func topMostViewController() -> UIViewController? {
        if let navigationController = self as? UINavigationController {
            return navigationController.topViewController?.topMostViewController()
        }
        else if let tabBarController = self as? UITabBarController {
            if let selectedViewController = tabBarController.selectedViewController {
                return selectedViewController.topMostViewController()
            }
            return tabBarController.topMostViewController()
        }
            
        else if let presentedViewController = self.presentedViewController {
            return presentedViewController.topMostViewController()
        }
        
        else {
            return self
        }
    }
}

用法：

在没有UIViewController实例的情况下获得topMostViewController

guard let viewController = UIViewController.topMostViewController() else { return }
print(viewController)

当您获取UIViewController实例的topMostViewController

let yourVC = UIViewController()
guard let vc = yourVC.topMostViewController() else { return }
print(vc)

Answer 13

在Swift 3中找到可见的viewController

if let viewControllers = window?.rootViewController?.childViewControllers {

     let prefs = UserDefaults.standard

     if viewControllers[viewControllers.count - 1] is ABCController{
        print("[ABCController] is visible")

     }
}

此代码查找最后添加的或最后一个活动控制器可见。

我在AppDelegate中使用它来查找活动视图Controller

Answer 14

你可以在AppDelegate中定义一个UIViewController变量，并在每个viewWillAppear中将变量设置为self。（但是dianz的答案是最好的答案。）

override func viewWillAppear(animated: Bool) {
    super.viewWillAppear(animated)
    let appDel = UIApplication.sharedApplication().delegate as! AppDelegate
    appDel.currentVC = self
}

Answer 15

iOS13 + //顶部大多数视图控制器

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

Answer 16

<块引用>

斯威夫特 5+

声明

func topViewController() -> UIViewController? {
    
    let keyWindow = UIApplication.shared.windows.filter {$0.isKeyWindow}.first

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

使用

topViewController()?.view.addSubview(UIView())

Answer 17

对于任何寻求快速5 / iOS 13+解决方案的人（自iOS 13起，keywindow被弃用）

extension UIApplication {

    class func getTopMostViewController() -> UIViewController? {
        let keyWindow = UIApplication.shared.windows.filter {$0.isKeyWindow}.first
        if var topController = keyWindow?.rootViewController {
            while let presentedViewController = topController.presentedViewController {
                topController = presentedViewController
            }
            return topController
        } else {
            return nil
        }
    }
}

Answer 18

在极少数情况下，使用自定义序列，最顶部的视图控制器不在导航堆栈或选项卡栏控制器中或未显示，而是将其视图插入到关键windown子视图的顶部。

在这种情况下，有必要检查UIApplication.shared.keyWindow.subviews.last == self.view是否确定当前视图控制器是否是最高的。

Answer 19

太多的口味，但没有一个反复阐述。结合以前的内容：

  "took": 84,
  "timed_out": false,
  "_shards": {
    "total": 5,
    "successful": 5,
    "skipped": 0,
    "failed": 0
  },
  "hits": {
    "total": 248,
    "max_score": 1,
    "hits": [
      {
        "_index": "countries-codes",
        "_type": "event",
        "_id": "Gx_gEGoBP2qGR-HHGMw3",
        "_score": 1,
        "_source": {
          "name": "Albanie",
          "alpha_2": "AL",
          "alpha_3": "ALB",
          "num": "8"
        }
      },

Answer 20

你把代码放在哪里？

我在我的演示中尝试了你的代码，我发现，如果你把代码放在

中

func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {

将失败，因为关键窗口已设置。

但我把你的代码放在某个视图控制器的

中

override func viewDidLoad() {

它只是有效。

Answer 21

对我来说最好的解决方案是使用功能扩展。使用此扩展名创建一个快捷文件

首先是UIWindow扩展：

public extension UIWindow {
    var visibleViewController: UIViewController? {
        return UIWindow.visibleVC(vc: self.rootViewController)
    }

    static func visibleVC(vc: UIViewController?) -> UIViewController? {
        if let navigationViewController = vc as? UINavigationController {
            return UIWindow.visibleVC(vc: navigationViewController.visibleViewController)
        } else if let tabBarVC = vc as? UITabBarController {
            return UIWindow.visibleVC(vc: tabBarVC.selectedViewController)
        } else {
            if let presentedVC = vc?.presentedViewController {
                return UIWindow.visibleVC(vc: presentedVC)
            } else {
                return vc
            }
        }
    }
}

在该文件添加功能内

func visibleViewController() -> UIViewController? {
    let appDelegate = UIApplication.shared.delegate
    if let window = appDelegate!.window {
        return window?.visibleViewController
    }
    return nil
}

如果要使用它，则可以在任何地方调用它。示例：

  override func viewDidLoad() {
    super.viewDidLoad()
      if let topVC = visibleViewController() {
             //show some label or text field 
    }
}

文件代码如下：

import UIKit

public extension UIWindow {
    var visibleViewController: UIViewController? {
        return UIWindow.visibleVC(vc: self.rootViewController)
    }

    static func visibleVC(vc: UIViewController?) -> UIViewController? {
        if let navigationViewController = vc as? UINavigationController {
            return UIWindow.visibleVC(vc: navigationViewController.visibleViewController)
        } else if let tabBarVC = vc as? UITabBarController {
            return UIWindow.visibleVC(vc: tabBarVC.selectedViewController)
        } else {
            if let presentedVC = vc?.presentedViewController {
                return UIWindow.visibleVC(vc: presentedVC)
            } else {
                return vc
            }
        }
    }
}

func visibleViewController() -> UIViewController? {
    let appDelegate = UIApplication.shared.delegate
    if let window = appDelegate!.window {
        return window?.visibleViewController
    }
    return nil
}

Answer 22

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 self.keyWindow?.rootViewController?.topMostViewController()
    }
}

Answer 23

  var topViewController: UIViewController? {
        guard var topViewController = UIApplication.shared.keyWindow?.rootViewController else { return nil }
        while let presentedViewController = topViewController.presentedViewController {
            topViewController = presentedViewController
        }
        return topViewController
    }

Answer 24

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
    }

Answer 25

在 SWIFT 5.2

中

您可以在下面的代码中使用

：

import UIKit

extension UIWindow {
    static func getTopViewController() -> UIViewController? {
        if #available(iOS 13, *){
            let keyWindow = UIApplication.shared.windows.filter {$0.isKeyWindow}.first
            
            if var topController = keyWindow?.rootViewController {
                while let presentedViewController = topController.presentedViewController {
                    topController = presentedViewController
                }
                return topController
            }
        } else {
            if var topController = UIApplication.shared.keyWindow?.rootViewController {
                while let presentedViewController = topController.presentedViewController {
                    topController = presentedViewController
                }
                return topController
            }
        }
        return nil
    }
}

Answer 26

runningTotal

Swift 5.2及更高版本

Answer 27

我使用下面的代码来获取topViewController-

它向后兼容旧的 iOS 版本并处理 UIScene

extension UIApplication {
    func topViewController() -> UIViewController? {
        var topViewController: UIViewController? = nil
        if #available(iOS 13, *) {
            for scene in connectedScenes {
                if let windowScene = scene as? UIWindowScene {
                    for window in windowScene.windows {
                        if window.isKeyWindow {
                            topViewController = window.rootViewController
                        }
                    }
                }
            }
        } else {
            topViewController = keyWindow?.rootViewController
        }
        while true {
            if let presented = topViewController?.presentedViewController {
                topViewController = presented
            } else if let navController = topViewController as? UINavigationController {
                topViewController = navController.topViewController
            } else if let tabBarController = topViewController as? UITabBarController {
                topViewController = tabBarController.selectedViewController
            } else {
                // Handle any other third party container in `else if` if required
                break
            }
        }
        return topViewController
    }
}

可以这样使用：

let topController = UIApplication.shared.topViewController()
topController?.present(controllerToPresent, animated: true, completion: nil)

获得最顶级的UIViewController

27 个答案: