迅速在UIAlertController之前執行segue

Question

我剛剛編寫了一個注冊頁面，其中如果用戶未在任何uitextfield中輸入文本，則它應該收到一條錯誤消息（UIAlert）； 否則（如果用戶在所有uitextfield中輸入文本）將顯示Firebase身份驗證的注冊頁面。

在我的代碼中，僅當身份驗證成功完成后，用戶才會定向到登錄頁面，否則應保留在帶有警告消息的注冊頁面中。

問題-我的代碼能夠生成警報消息，但是即使有錯誤，它也會同時使用戶自動登錄頁面。 這意味着它正在執行segue，使用戶登錄頁面，即不管警報消息如何，segue都將平倉。

誰能幫我為什么會這樣？

 @IBAction func registerPressed(_ sender: Any) {

    if nameText.text!.isEmpty || genderText.text!.isEmpty || countryText.text!.isEmpty || yourSchool.text!.isEmpty || yourClass.text!.isEmpty {

        print("Please fill all fields") //my code is printing this error

        //alert message popup - my code is ble to produce this alert but same it is performing segue and taking user to signin page
        //ideally, i want user to be in signup page unless all criteria meet

        let alertController = UIAlertController(title: "Error", message: "Please fill all fields", preferredStyle: .alert)
        alertController.addAction(UIAlertAction(title: "Ok", style: .default, handler: { (action:UIAlertAction) in
        print("Okay")
        }))

        let alertWindow = UIWindow(frame: UIScreen.main.bounds)
        alertWindow.rootViewController = UIViewController()
        alertWindow.windowLevel = UIWindowLevelAlert
        alertWindow.makeKeyAndVisible()
        alertWindow.rootViewController?.present(alertController, animated: true, completion: nil)


    }

    else {

        Auth.auth().createUser(withEmail: yourEmail.text!, password: yourPassword.text!) { (user, error) in

                    if error != nil {

                        ///print errror message

                        let alertController = UIAlertController(title: "Error", message: error?.localizedDescription, preferredStyle: .alert)
                        alertController.addAction(UIAlertAction(title: "Ok", style: .default, handler: { (action:UIAlertAction) in
                            print("Okay")
                        }))

                        let alertWindow = UIWindow(frame: UIScreen.main.bounds)
                        alertWindow.rootViewController = UIViewController()
                        alertWindow.windowLevel = UIWindowLevelAlert + 1;
                        alertWindow.makeKeyAndVisible()
                        alertWindow.rootViewController?.present(alertController, animated: true, completion: nil)

                    }

                    else {

                        print("You have successfully signed up")

                        self.performSegue(withIdentifier: "JoinUs2SignPage", sender: self)

                        //updating user information
                        let userID = Auth.auth().currentUser!.uid
                        let usertype: String = "Student"
                        self.ref.child("users").child(userID).setValue(["usertype": usertype ,"username": self.nameText.text!, "usergender": self.genderText.text!, "usercountry": self.countryText.text!, "userschool": self.yourSchool.text!, "userclass": self.yourClass.text!,])
                        }
            }
        }

}

Answer 1

從這段代碼來看，似乎沒有什么錯。 但是，您應該在Auth.auth().createUser(...)運行時阻止UI。 否則，您有可能在一切正確的情況下調用registerPressed ，但是隨后從標簽中刪除了文本並在回調之前再次調用它。 這樣，您將收到警報， 然后調用segue。

您呈現警報的方式也很瘋狂。 無需創建新窗口，而是向其添加視圖控制器和所有爵士樂，只需調用self.present(alertController, animated: true) 。 例如

let alertController = UIAlertController(title: "Error", message: "Please fill all fields", preferredStyle: .alert)
alertController.addAction(UIAlertAction(title: "Ok", style: .default, handler: { (action:UIAlertAction) in
    print("Okay")
}))

self.present(alertController, animated: true)

Answer 2

刪除序列並以編程方式推送到目標視圖控制器。

    self.navigationController?.pushViewController(destinationVC, animated: true)

Answer 3

我犯了一個愚蠢的錯誤，我直接在IBAction上創建了segue，因此每當我按下按鈕時，它都會執行segue，而與UIAlerts無關。 我的更新代碼如下：

   @IBAction func registerPressed(_ sender: Any) {

    if nameText.text!.isEmpty || genderText.text!.isEmpty || countryText.text!.isEmpty || yourSchool.text!.isEmpty || yourClass.text!.isEmpty {

        //alert message popup

        let alertController = UIAlertController(title: "Error", message: "Please fill all fields", preferredStyle: .alert)
        alertController.addAction(UIAlertAction(title: "Ok", style: .default, handler: { (action:UIAlertAction) in
        print("Okay")
        }))

        self.present(alertController, animated: true, completion: nil)


    }

    else {

        Auth.auth().createUser(withEmail: yourEmail.text!, password: yourPassword.text!) { (user, error) in

                    if error != nil {

                        ///print errror message

                        let alertController = UIAlertController(title: "Error", message: error?.localizedDescription, preferredStyle: .alert)
                        alertController.addAction(UIAlertAction(title: "Ok", style: .default, handler: { (action:UIAlertAction) in
                            print("Okay")
                        }))

                        self.present(alertController, animated: true, completion: nil)

                    }

                    else {

                        let alertController = UIAlertController(title: "Congratulation", message: "You have successfully signed up", preferredStyle: .alert)
                        alertController.addAction(UIAlertAction(title: "Get Started", style: .default, handler: { (action:UIAlertAction) in

                            self.performSegue(withIdentifier: "back2SignPage", sender: self)
                        }))

                        self.present(alertController, animated: true, completion: nil)

                        //updating user information
                        let userID = Auth.auth().currentUser!.uid
                        let usertype: String = "Student"
                        self.ref.child("users").child(userID).setValue(["usertype": usertype ,"username": self.nameText.text!, "usergender": self.genderText.text!, "usercountry": self.countryText.text!, "userschool": self.yourSchool.text!, "userclass": self.yourClass.text!,])
                        }
            }
        }

}