textField 最大长度和邮政编码验证

Posted 2023-02-23

【中文标题】textField 最大长度和邮政编码验证

【英文标题】：textField Maximum length and Postal Code validation

【发布时间】：2020-05-06 16:19:36

【问题描述】：

我有一个文本字段来输入加拿大邮政编码。我正在使用以下代码来确保格式正确，否则会显示警告，指出格式不正确。这在saveBtnClick 上运行没有问题；但由于validZipCode 函数，我无法在该字段中输入，因为它继续将false 返回到textField。我还需要确保该字段的最大字符长度不超过7 个字符，因此用户不能输入超过七个字。我看到许多解决方案仅用于设置最大长度；但无法弄清楚如何使用我在此处提到的用于邮政编码验证的现有条件来执行此操作。这是我当前的代码：

@IBOutlet weak var postalCodeTextField: UITextField!

override func viewDidLoad() 
    phoneNumberTextField.delegate = self
    postalCodeTextField.delegate = self


func validZipCode(postalCode:String)->String
    let postalcodeRegex = "^[a-zA-Z][0-9][a-zA-Z][- ]*[0-9][a-zA-Z][0-9]$"
    let pinPredicate = NSPredicate(format: "SELF MATCHES %@", postalcodeRegex)
    let bool = pinPredicate.evaluate(with: postalCode) as Bool
  return bool.description


@IBAction func saveBtnClicked(_ sender: Any) 

    let isPostalCodeValid = validZipCode(postalCode: postalCodeTextField.text ?? "")

    if isPostalCodeValid == "false" 

        simpleAlert(title: "Error!", msg: "Please enter a valid CA postal code")

     else
        if isPostalCodeValid == "true" 
       //the postalCaode is correct formatting
    






func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool 
        guard let text = textField.text else  return false 
        let newString = (text as NSString).replacingCharacters(in: range, with: string)

    if textField == phoneNumberTextField 
        textField.text = formattedNumber(number: newString)
     else

        if textField == postalCodeTextField 
            textField.text = validZipCode(postalCode: newString)
    

    return false

【参考方案1】：

如果我们将单个字符传递给函数validZipCode，它将始终返回false。因此，请验证单击saveButton 的谓词。

class ViewController: UIViewController, UITextFieldDelegate 
    @IBOutlet weak var postalCodeTextField: UITextField!

       override func viewDidLoad() 
            postalCodeTextField.delegate = self
        

        func validZipCode(postalCode:String)->Bool
              let postalcodeRegex = "^[a-zA-Z][0-9][a-zA-Z][- ]*[0-9][a-zA-Z][0-9]$"
            let pinPredicate = NSPredicate(format: "SELF MATCHES %@", postalcodeRegex)
            let bool = pinPredicate.evaluate(with: postalCode) as Bool
            return bool
        

        @IBAction func saveBtnClicked(_ sender: Any) 

            let isPostalCodeValid = validZipCode(postalCode: postalCodeTextField.text ?? "")

            if isPostalCodeValid == false 
                print("false")
               // simpleAlert(title: "Error!", msg: "Please enter a valid CA postal code")

             else
                if isPostalCodeValid == true 
                    print("true")
               //the postalCaode is correct formatting
            

        

        func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool 

            let currentText = textField.text ?? ""
             guard let stringRange = Range(range, in: currentText) else  return false 

            if textField == postalCodeTextField 
                // add their new text to the existing text
                let updatedText = currentText.replacingCharacters(in: stringRange, with: string)

                // make sure the result is under 7 characters
                return updatedText.count <= 7
            else
                return true
            
        

    

希望这会有所帮助！！

【讨论】：

这很棒。谢谢！你怎么能让邮政编码在第三个字符后包含一个空格？所以当你在那里输入时，结果看起来像XXX XXX，总共是 7 个，第四个总是一个空格

您可以将委托方法修改为， if textField == postalCodeTextField // 将它们的新文本添加到现有文本中 let updatedText = currentText.replacingCharacters(in: stringRange, with: string) if(currentText .count == 3) postalCodeTextField.text = postalCodeTextField.text！ + " " // 确保结果小于 7 个字符 return updatedText.count

我确实做到了；但问题是当我尝试退格和删除时；一旦到达字符 3，它就不允许用户进一步删除，因为 character.count 从 4 变为 3 - 这里是说在 3 个字符处放置一个空格，使其变为 4 个字符

好的，所以我使用这个解决方案来检测我们是否在退格，在这种情况下我不输入空格。否则我放空间：***.com/questions/29504304/…