ios - 将 UITextField MM/YY 格式化为过期时间

Question

尝试为信用卡到期日设置一个 textField 下面的代码可以正常工作，只是想改变行为，目前当您从第三个数字开始输入时 /字符将被添加为过期格式。如果我想在用户键入第二个数字后添加 / 字符怎么办？例如，如果用户键入 01 直接插入分隔符

open func reformatAsExpiration(_ textField: UITextField) {
        guard let string = textField.text else { return }
        let expirationString = String(ccrow.expirationSeparator)
        let cleanString = string.replacingOccurrences(of: expirationString, with: "", options: .literal, range: nil)
        if cleanString.length >= 3 {
            let monthString = cleanString[Range(0...1)]
            var yearString: String
            if cleanString.length == 3 {
                yearString = cleanString[2]
            } else {
                yearString = cleanString[Range(2...3)]
            }
            textField.text = monthString + expirationString + yearString
        } else {
            textField.text = cleanString
        }
    }

Answer 1

Swift 5 :

这是验证输入的月份和年份的解决方案

使用 TextField 委托(delegate)方法 shouldChangeCharactersIn

func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
    guard let oldText = textField.text, let r = Range(range, in: oldText) else {
        return true
    }
    let updatedText = oldText.replacingCharacters(in: r, with: string)

    if string == "" {
        if updatedText.count == 2 {
            textField.text = "\(updatedText.prefix(1))"
            return false
        }
    } else if updatedText.count == 1 {
        if updatedText > "1" {
            return false
        }
    } else if updatedText.count == 2 {
        if updatedText <= "12" { //Prevent user to not enter month more than 12
            textField.text = "\(updatedText)/" //This will add "/" when user enters 2nd digit of month
        }
        return false
    } else if updatedText.count == 5 {
        self.expDateValidation(dateStr: updatedText)
    } else if updatedText.count > 5 {
        return false
    }

    return true
}

下面函数中的验证逻辑

func expDateValidation(dateStr:String) {

    let currentYear = Calendar.current.component(.year, from: Date()) % 100   // This will give you current year (i.e. if 2019 then it will be 19)
    let currentMonth = Calendar.current.component(.month, from: Date()) // This will give you current month (i.e if June then it will be 6)

    let enteredYear = Int(dateStr.suffix(2)) ?? 0 // get last two digit from entered string as year
    let enteredMonth = Int(dateStr.prefix(2)) ?? 0 // get first two digit from entered string as month
    print(dateStr) // This is MM/YY Entered by user

    if enteredYear > currentYear {
        if (1 ... 12).contains(enteredMonth) {
            print("Entered Date Is Right")
        } else {
            print("Entered Date Is Wrong")
        }
    } else if currentYear == enteredYear {
        if enteredMonth >= currentMonth {
            if (1 ... 12).contains(enteredMonth) {
               print("Entered Date Is Right")
            } else {
               print("Entered Date Is Wrong")
            }
        } else {
            print("Entered Date Is Wrong")
        }
    } else {
       print("Entered Date Is Wrong")
    }

}