我一直在努力创建一个UIAlertView在Swift,但由于某种原因,我不能得到正确的声明,因为我得到这个错误:

无法找到一个超载的'init'接受提供的 参数

我是这样写的:

let button2Alert: UIAlertView = UIAlertView(title: "Title", message: "message",
                     delegate: self, cancelButtonTitle: "OK", otherButtonTitles: nil)

然后我使用:

button2Alert.show()

到目前为止,它正在崩溃,我只是不能得到正确的语法。


当前回答

或者这样做

        let alert = UIAlertController(title: "Alert", message: "Saved Successfully", preferredStyle: UIAlertController.Style.alert)
        alert.addAction(UIAlertAction(title: "Ok", style: UIAlertAction.Style.default, handler: nil))
        self.present(alert, animated: true, completion: nil)

其他回答

使用此代码显示alertview

  let alertController = UIAlertController(title: "Hello  Coders", message: "your alert message", preferredStyle: .Alert)
        let defaultAction = UIAlertAction(title: "Close Alert", style: .Default, handler: nil)
        alertController.addAction(defaultAction)

        presentViewController(alertController, animated: true, completion: nil)

Swift显示警报使用UIAlertController

显示UIAlertView在swift语言:-

Protocol UIAlertViewDelegate

let alert = UIAlertView(title: "alertView", message: "This is alertView", delegate:self, cancelButtonTitle:"Cancel", otherButtonTitles: "Done", "Delete")
alert.show()

显示UIAlertViewController在swift语言:-

let alert = UIAlertController(title: "Error", message: "Enter data in Text fields", preferredStyle: UIAlertControllerStyle.Alert)
alert.addAction(UIAlertAction(title: "OK", style: UIAlertActionStyle.Default, handler: nil))
self.presentViewController(alert, animated: true, completion: nil)

我已经做了一个单例类,以便从应用程序的任何地方使用:https://github.com/Swinny1989/Swift-Popups

然后你可以创建一个带有多个按钮的弹出窗口,如下所示:

Popups.SharedInstance.ShowAlert(self, title: "Title goes here", message: "Messages goes here", buttons: ["button one" , "button two"]) { (buttonPressed) -> Void in
    if buttonPressed == "button one" { 
      //Code here
    } else if buttonPressed == "button two" {
        // Code here
    }
}

或者弹出一个按钮,像这样:

Popups.SharedInstance.ShowPopup("Title goes here", message: "Message goes here.")

适用于13.0以上版本 使用SceneDelegate

适用于所有类型的课程

static func showWindowAlert(alertMessage: String, inVC:UIViewController) {
        DispatchQueue.main.async(execute: {
            guard let windowScene = UIApplication.shared.connectedScenes.first as? UIWindowScene,
                let sceneDelegate = windowScene.delegate as? SceneDelegate
              else {
                return
              }
            sceneDelegate.window?.rootViewController = inVC
            sceneDelegate.window?.windowLevel = UIWindow.Level.alert + 1
        
            let alert2 = UIAlertController(title: App_Name, message: alertMessage, preferredStyle: .alert)
            let defaultAction2 = UIAlertAction(title: "OK", style: .default, handler: { action in
            })
            alert2.addAction(defaultAction2)
        
            sceneDelegate.window?.makeKeyAndVisible()
        
            sceneDelegate.window?.rootViewController?.present(alert2, animated: true, completion: nil)
        })
    }

它不工作的原因是因为你传递给函数的某个值不正确。swift不像Objective-C,你可以把nil放在类类型的参数中,没有任何限制(可能是)。参数otherButtonTitles被定义为非可选的,其类型的末尾没有(?)。所以你必须传递一个具体的值给它。