所以,我今天已经更新到Xcode 10和iOS 12,现在当我从UINavigationController调用topViewController时收到以下错误消息:
模糊使用“ topViewController”
if let myVC = navigationController.topViewController as? MyViewController {}
即使以下代码可以正常工作。
if let myVC = navigationController.visibleViewController as? MyViewController {}
有人知道iOS 12中对此有何变化吗?
答案 0 :(得分:1)
我可以建议您使用此功能,以获取topViewContoller作为扩展。如您所料,易于使用。
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
}
}
用法:
UIApplication.topViewController()