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
你把密码放哪了?
我在我的演示中尝试了你的代码，我发现，如果你把代码放进去
func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
将失败，因为关键窗口已经设置。
但我把你的代码放到了视图控制器中
override func viewDidLoad() {
它就是有用。
其他回答
使用这段代码找到top most UIViewController
func getTopViewController() -> UIViewController? {
var topController: UIViewController? = UIApplication.shared.keyWindow?.rootViewController
while topController?.presentedViewController != nil {
topController = topController?.presentedViewController
}
return topController
}
试试这个
let topVisibleVC = UIApplication.shared.keyWindow?.rootViewController?.visibleViewController
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 UIApplication {
public var mainKeyWindow: UIWindow? {
if #available(iOS 13, *) {
return UIApplication.shared.connectedScenes
.filter { $0.activationState == .foregroundActive }
.first(where: { $0 is UIWindowScene })
.flatMap { $0 as? UIWindowScene }?.windows
.first(where: \.isKeyWindow)
} else {
return UIApplication.shared.windows.first { $0.isKeyWindow }
}
}
public var rootViewController: UIViewController? {
guard let keyWindow = UIApplication.shared.mainKeyWindow, let rootViewController = keyWindow.rootViewController else {
return nil
}
return rootViewController
}
public func topViewController(controller: UIViewController? = UIApplication.shared.rootViewController) -> UIViewController? {
if controller == nil {
return topViewController(controller: rootViewController)
}
if let navigationController = controller as? UINavigationController {
return topViewController(controller: navigationController.visibleViewController)
}
if let tabController = controller as? UITabBarController {
if let selectedViewController = tabController.selectedViewController {
return topViewController(controller: selectedViewController)
}
}
if let presentedViewController = controller?.presentedViewController {
return topViewController(controller: presentedViewController)
}
return controller
}
}
Swift 5.2及以上版本
