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
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
}
}
其他回答
你可以在AppDelegate中定义一个UIViewController变量，并在每个viewWillAppear中设置这个变量为self。(然而，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
}
@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
}
在一个非常罕见的情况下，使用自定义segue，最顶层的视图控制器不在导航堆栈或选项卡栏控制器中或被呈现，但它的视图被插入到关键窗口子视图的顶部。
在这种情况下，有必要检查UIApplication.shared.keyWindow.subviews.last == self。视图来确定当前视图控制器是否是最顶端的。
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
}
}
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()
}
}
