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
iOS13+ //top最多视图控制器
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
我喜欢@dianz的回答，下面是swift 3的版本。它基本上是一样的，但他少了一个大括号，一些语法/变量/方法名已经改变了。所以它就在这里!
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
}
}
用法仍然是一样的:
if let topController = UIApplication.topViewController() {
print("The view controller you're looking at is: \(topController)")
}
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。
对于swift 4 / 5 +获取topmost 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)
}
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
}
