在所有视图控制器中创建警报功能 - swift

Question

我正在尝试声明一个用于在我的应用中显示警报的函数。为避免重复工作，我尝试对我的所有应用程序使用相同的功能。我试图通过创建一个带有函数 showNotification 的类来做到这一点。但是当我创建该类的对象并调用该方法时，什么也没有发生。我该怎么做？

class SharedPropertiesAndMetods : UIViewController {

    func showNotification(title: String, message: String)
    {
        let alertController = UIAlertController(title: title, message: message, preferredStyle: .alert)
        let defaultAction = UIAlertAction(title: "تائید", style: .default, handler: nil)
        alertController.addAction(defaultAction)
        present(alertController, animated: true, completion: nil)
    }

}

Answer 1

使用这样的扩展

extension UIViewController {
  func showAlert(title: String, message: String) {
    let alertController = UIAlertController(title: title, message:
      message, preferredStyle: .alert)
    alertController.addAction(UIAlertAction(title: "OK", style: .default, handler: {action in
    }))
    self.present(alertController, animated: true, completion: nil)
  }
}

这样调用函数

self.showAlert(title: "hi", message: "test")

Answer 2

我要做的是创建一个“通用”视图控制器来完成这项工作，而不是从它继承：

1.如果您想在每次视图确实出现时显示警报：

class GenericViewController: UIViewController {

    // MARK: - View lifecycle -

    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)
        if let notification = self.shouldDisplayAlertNotification() {
            self.showNotification(notification)
        }
    }

    // MARK: - Internal methods -

    func shouldDisplayAlertNotification() -> AlertNotification? {
        return nil
    }

    // MARK: - Private methods -

    private func showNotification(_ alertNotification: AlertNotification) {
    }

}

class MyController: GenericViewController {

    override func shouldDisplayAlertNotification() -> AlertNotification? {
        return AlertNotification(title: "Title", message: "Message")
    }

}

AlertNotification 是您的自定义模型类：

class AlertNotification {
    var title: String
    var message: String

    init(title: String, message: String) {
        self.title = title
        self.message = message
    }
}

这样，只有覆盖shouldDisplayAlertNotification的VC才会显示警报。

2。如果您想在“需求”时显示警报：

按照建议，扩展 UIViewController

extension UIViewController {
    func showNotification(title: String, message: String) {
    }
}

Answer 3

其实你可以在类之外的任何地方声明一个简单的方法。

func showAlertWithCompletion(message:String,okTitle:String,cancelTitle:String?,completionBlock:@escaping (_ okPressed:Bool)->()){
    let alertController = UIAlertController(title: AppName, message: message, preferredStyle: .alert)
    let okAction = UIAlertAction(title: okTitle, style: .default) { (ok) in
        completionBlock(true)
    }
    alertController.addAction(okAction)
    if let cancelTitle = cancelTitle{
        let cancelOption = UIAlertAction(title: cancelTitle, style: .cancel, handler: { (axn) in
            completionBlock(false)

        })
        alertController.addAction(cancelOption)
    }

    if let topController = UIWindow.topViewController(){
      topController.present(alertController, animated: true, completion: nil)
    }

}

这样，无论您调用它，您都会在完成句柄中获得 ok 按钮按下回调，甚至按照@Ganesh Kumar 的描述进行扩展

Answer 4

为什么不只是一个扩展

extension UIViewController {

    func showNotification(title: String, message: String)
    {
        let alertController = UIAlertController(title: title, message: message, preferredStyle: .alert)
        let defaultAction = UIAlertAction(title: "تائید", style: .default, handler: nil)
        alertController.addAction(defaultAction)
        present(alertController, animated: true, completion: nil)
    }
}

Answer 5

您可以使用此视图控制器扩展在整个应用程序中呈现警报视图。 https://github.com/SumitKr88/UIViewController-ShowAlertView/blob/master/UIViewController%2BExtensions.swift

extension UIViewController {

/// Show alert view
/// - Parameter title: title of alert
/// - Parameter message: message of alert
/// - Parameter actionTitles: List of action button titles(ex : "OK","Cancel" etc)
/// - Parameter style: Style of the buttons
/// - Parameter actions: actions repective to each actionTitles
/// - Parameter preferredActionIndex: Index of the button that need to be shown in bold. If nil is passed then it takes cancel as default button.

/**
 Example usage:-
 Just make sure actionTitles and actions array the same count.

 /********** 1. Pass nil if you don't need any action handler closure. **************/
 self.showAlert(title: "Title", message: "message", actionTitles: ["OK"], style: [.deafult], actions: [nil])

 /*********** 2. Alert view with one action **************/

 ///     let okActionHandler: ((UIAlertAction) -> Void) = {(action) in
 //Perform action of Ok here
 }
 self.showAlert(title: "Title", message: "message", actionTitles: ["OK", "CANCEL"], style: [.default, .cancel], actions: [okayActionHandler, nil])

 /********** 3.Alert view with two actions **************/

 let okActionHandler: ((UIAlertAction) -> Void) = {(action) in
 //Perform action of ok here
 }

 let cancelActionHandler: ((UIAlertAction) -> Void) = {(action) in
 //Perform action of cancel here
 }

 self.showAlert(title: "Title", message: "message", actionTitles: ["OK", "CANCEL"], style: [.default, .cancel], actions: [okActionHandler,cancelActionHandler], preferredActionIndex: 1)
 */

public func showAlert(title: String?,
                      message: String?,
                      actionTitles: [String?],
                      style: [UIAlertAction.Style],
                      actions: [((UIAlertAction) -> Void)?],
                      preferredActionIndex: Int? = nil) {
    let alert = UIAlertController(title: title, message: message, preferredStyle: .alert)
    for (index, title) in actionTitles.enumerated() {
        let action = UIAlertAction(title: title, style: style[index], handler: actions[index])
        alert.addAction(action)
    }
    if let preferredActionIndex = preferredActionIndex { alert.preferredAction = alert.actions[preferredActionIndex] }
    self.present(alert, animated: true, completion: nil)
}}

Answer 6

您可以为 alertController 创建扩展，还可以选择操作处理程序。这将允许根据是否需要处理程序使用两个不同的警报控制器。

extension  UIAlertControler {

class func genericErrorAlert(forAlert message: String, completion: ((UIAlertAction) -> Void)? = nil )

    let alert = UIAlertController(title: "Error", message: message, preferredStyle: .alert)

    alert.addAction(UIAlertAction(title: "OK", style: .cancel, handler: completion))

    return alert
  }
}

Answer 7

您还可以在您的应用中创建一个 util 文件，因为您可以添加任何可重用的方法或函数并在您的应用中的任何位置使用它，

导入基础 导入 UIKit

//标记：-警报

func showMessage(title: String, message: String!, VC: UIViewController) {

let alert : UIAlertController = UIAlertController(title: "", message: message, preferredStyle: UIAlertControllerStyle.alert)
let okAction = UIAlertAction(title: "OK", style: UIAlertActionStyle.default) {
    UIAlertAction in
}
alert.addAction(okAction)
VC.present(alert, animated: true, completion: nil)

}