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
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
}
}
Use
topViewController()?.view.addSubview(UIView())
其他回答
presentViewController显示一个视图控制器。它不会返回一个视图控制器。如果你不使用UINavigationController，你可能正在寻找presenttedviewcontroller，你需要从根开始，向下迭代所呈现的视图。
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
}
适用于iOS 13+
let keyWindow = UIApplication.shared.windows.filter {$0.isKeyWindow}.first
if var topController = keyWindow?.rootViewController {
while let presentedViewController = topController.presentedViewController {
topController = presentedViewController
}
// topController should now be your topmost view controller
}
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。
在SWIFT 5.2中
你可以使用下面的代码:
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
}
}
太多口味了，但都不是一种反复精心制作的。结合前面的内容:
func topMostController() -> UIViewController? {
var from = UIApplication.shared.keyWindow?.rootViewController
while (from != nil) {
if let to = (from as? UITabBarController)?.selectedViewController {
from = to
} else if let to = (from as? UINavigationController)?.visibleViewController {
from = to
} else if let to = from?.presentedViewController {
from = to
} else {
break
}
}
return from
}
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。
