如果没有UINavigationController，我似乎无法得到最顶端的UIViewController。以下是我目前所掌握的:
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似乎也不是nil值，所以可选的链接应该不是问题。
注意:这样做不是一个好主意。它打破了MVC模式。
当前回答
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;
}
}
}
}
其他回答
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
}
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")
}
}
这段代码找到最后添加的或最后可见的活动控制器。
我已经在AppDelegate中使用它来查找活动视图控制器
@AlberZou略有变化，使用计算变量而不是函数
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
}
对我来说，最好的解决方案是一个带有函数的扩展。 用这个扩展名创建一个swift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
}
}
}
}
在该文件中添加函数
func visibleViewController() -> UIViewController? {
let appDelegate = UIApplication.shared.delegate
if let window = appDelegate!.window {
return window?.visibleViewController
}
return nil
}
如果你想使用它，你可以在任何地方调用它。 例子:
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
}
我使用下面的代码来获得topViewController-
它向后兼容旧的iOS版本，并照顾UIScene太
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
}
}
它可以这样使用:
let topController = UIApplication.shared.topViewController()
topController?.present(controllerToPresent, animated: true, completion: nil)
