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
对于Swift 5+， iOS 13 +
extension UIViewController {
static func topMostViewController() -> UIViewController? {
if #available(iOS 13.0, *) {
let keyWindow = UIApplication.shared.windows.filter {$0.isKeyWindow}.first
return keyWindow?.rootViewController?.topMostViewController()
}
return UIApplication.shared.keyWindow?.rootViewController?.topMostViewController()
}
func topMostViewController() -> UIViewController? {
if let navigationController = self as? UINavigationController {
return navigationController.topViewController?.topMostViewController()
}
else if let tabBarController = self as? UITabBarController {
if let selectedViewController = tabBarController.selectedViewController {
return selectedViewController.topMostViewController()
}
return tabBarController.topMostViewController()
}
else if let presentedViewController = self.presentedViewController {
return presentedViewController.topMostViewController()
}
else {
return self
}
}
}
用法:
当你在没有UIViewController实例的情况下获取topMostViewController时
guard let viewController = UIViewController.topMostViewController() else { return }
print(viewController)
当你获取UIViewController实例的topMostViewController时
let yourVC = UIViewController()
guard let vc = yourVC.topMostViewController() else { return }
print(vc)
其他回答
有这个扩展
斯威夫特2。*
extension UIApplication {
class func topViewController(controller: UIViewController? = UIApplication.sharedApplication().keyWindow?.rootViewController) -> UIViewController? {
if let navigationController = controller as? UINavigationController {
return topViewController(navigationController.visibleViewController)
}
if let tabController = controller as? UITabBarController {
if let selected = tabController.selectedViewController {
return topViewController(selected)
}
}
if let presented = controller?.presentedViewController {
return topViewController(presented)
}
return controller
}
}
斯威夫特3
extension UIApplication {
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
}
}
然后你可以在控制器的任何地方使用它
if let topController = UIApplication.topViewController() {
}
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;
}
}
}
}
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
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()
}
}
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
}
