Swift编写一个以self作为输入的函数

我有来自不同位置的警报，所以我决定调用一个函数。

func alertSCFlag(x: Int) { var alert = UIAlertController() switch x { case 1: alert = UIAlertController(title: "Not Finished", message: "sorry but you must give the project a title and description", preferredStyle: UIAlertControllerStyle.alert) default: alert = UIAlertController(title: "Not Finished", message: "sorry but you need to choose a type of project", preferredStyle: UIAlertControllerStyle.alert) } alert.addAction(UIAlertAction(title: "Ok", style: UIAlertActionStyle.default, handler: nil)) self.present(alert, animated: true, completion: nil) } 

问题是，自我显然不是普遍的，我无法弄清楚如何通过它。 有没有办法通过自我或更好的方式来解决整体问题？

Answer 1

你需要的是扩展UIViewController这样你不需要传递任何视图控制器作为参数，self将始终是一个视图控制器。 并确保从主线程调用视图控制器的当前方法present(_ viewControllerToPresent: UIViewController, animated flag: Bool, completion: (() -> Void)? = nil) ：

 extension UIViewController { enum Message: CustomStringConvertible { case missingTitle, chooseProject var description: String { let message: String switch self { case .missingTitle: message = "sorry but you must give the project a title and description" case .chooseProject: message = "sorry but you need to choose a type of project" } return message } } func alertSCFlag(title: String = "Not Finished", message: Message) { let alert = UIAlertController(title: title, message: message.description, preferredStyle: .alert) alert.addAction(UIAlertAction(title: "Ok", style: .default)) DispatchQueue.main.async { self.present(alert, animated: true) } } } 

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用法：

 let vc = UIViewController() vc.alertSCFlag(message: .chooseProject)