我有一个主类AddFriendsController,它运行以下代码行:
I have a main class, AddFriendsController, that runs the following line of code:
ErrorReporting.showMessage("Error", msg: "Could not add student to storage.")然后我有了这个ErrorReporting.swift文件:
导入基金会
class ErrorReporting { func showMessage(title: String, msg: String) { let alert = UIAlertController(title: title, message: msg, preferredStyle: UIAlertControllerStyle.Alert) alert.addAction(UIAlertAction(title: "Ok", style: UIAlertActionStyle.Default, handler: nil)) self.presentViewController(alert, animated: true, completion: nil) } }很显然,self在这里不起作用,给我一个错误.我希望在许多不同的swift文件中使用相同的方法,如何引用当前打开的视图控制器(在这种情况下为AddFriendsController)?
Obviously, self wouldn't work here, and is giving me an error. How can I refer to the currently open view controller (i.e. AddFriendsController in this circumstance), as I am wishing to use this same method in many different swift files?
谢谢.
推荐答案您可以为UIApplication创建扩展方法(例如),该方法将返回topViewController:
You can create extension method for UIApplication (for example) which will return your topViewController:
extension UIApplication { static func topViewController(base: UIViewController? = UIApplication.sharedApplication().delegate?.window??.rootViewController) -> UIViewController? { if let nav = base as? UINavigationController { return topViewController(nav.visibleViewController) } if let tab = base as? UITabBarController, selected = tab.selectedViewController { return topViewController(selected) } if let presented = base?.presentedViewController { return topViewController(presented) } return base } }然后您的课程将如下所示:
And then your class will look like this:
class ErrorReporting { static func showMessage(title: String, msg: String) { let alert = UIAlertController(title: title, message: msg, preferredStyle: UIAlertControllerStyle.Alert) alert.addAction(UIAlertAction(title: "Ok", style: UIAlertActionStyle.Default, handler: nil)) UIApplication.topViewController()?.presentViewController(alert, animated: true, completion: nil) } }方法必须为static才能将其称为ErrorReporting.showMessage.
Method need to be static to be able to call it as ErrorReporting.showMessage.
更多推荐
如何在Swift中显示来自另一个班级的警报?
发布评论