swift - if 语句执行自己而不是其他人

Question

我这里有一个代码，每次运行它时，只有声明“所有字段都是必需的”的 if 语句有效，但不仅在必须调用它时，它实际上会代替其他语句运行。因此，即使所有字段都已完成，无论我做什么，我都会收到“所有字段都需要”作为警告消息。这是代码，感谢所有帮助，在此先感谢您。

import UIKit

class RegisterPageViewController: UIViewController {


@IBOutlet weak var userEmailTextField: UITextField!
@IBOutlet weak var userPasswordTextField: UITextField!
@IBOutlet weak var repeatPasswordTextField: UITextField!

override func viewDidLoad() {
    super.viewDidLoad()

    // Do any additional setup after loading the view.
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}
@IBAction func registerButtonTapped(_ sender: AnyObject) {

    let userEmail = ""
    let userPassword = ""
    let userRepeatPassword = ""



    // Check for empty fields


    if (userEmail.isEmpty || userPassword.isEmpty || 
userRepeatPassword.isEmpty)
    {
        // Display Alert Message
        displayMyAlertMessage(userMessage:"All fields are required")
        return
    }

    //Check if passwords match
    if (userPassword != userRepeatPassword)
    {
        // Display an alert message
        displayMyAlertMessage(userMessage:"Passwords do not match")
        return
    }


    // Store data
    UserDefaults.standard.set(userEmail, forKey:"userEmail")
    UserDefaults.standard.set(userEmail, forKey:"userPassword")
    UserDefaults.standard.synchronize()


    // Display alert message with confirmation
    _ = UIAlertController(title:"Alert", message:"Registration is 
successfull. Thank you!", 
preferredStyle:UIAlertControllerStyle.alert);

    _ = UIAlertAction(title:"Ok", style:UIAlertActionStyle.default)
    {
        action in
        self.dismiss(animated: true, completion:nil)
    }



 }


func displayMyAlertMessage(userMessage:String)
{

let myAlert = UIAlertController(title:"Alert", message: userMessage, 
preferredStyle:UIAlertControllerStyle.alert);


let okAction = UIAlertAction(title:"Ok", 
style:UIAlertActionStyle.default, handler:nil)

myAlert.addAction(okAction)

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


}


}

Answer 1

您是否曾为 userEmail、userPassword、userRepeatPassword 分配任何值？您在函数开始时将它们初始化为空，看起来它们的值永远不会改变。

与其在函数中声明它们，不如尝试使用类级变量，并将它们链接到 Storyboard 中的文本字段。

@IBOutlet weak var userEmail: UITextField!
@IBOutlet weak var userPassword: UITextField!
@IBOutlet weak var userRepeatPassword: UITextField!

@IBAction func registerButtonTapped(_ sender: AnyObject) {
    // Check for empty fields
    if (self.userEmail.text.isEmpty || self.userPassword.text.isEmpty || self.userRepeatPassword.text.isEmpty) {
        // Display Alert Message
        displayMyAlertMessage(userMessage:"All fields are required")
        return
    }
    ...
}