swift - UITextfield 值在按下 6、7、8、9 时递增并限制编辑

Question

UITextField 响应不正确。我无法删除当前值，但是当我按下键盘上的数字 6、7、8、9 时，值会发生变化。此文本字段的方法是使用 UITextfield 委托设置的。当我屏蔽 shouldChangeCharactersIn 下的代码部分时，它可以工作。我的问题是为什么代码限制文本字段输入并且仅在键盘上按下某些数字时才响应？

func textFieldDidEndEditing(_ textField: UITextField) {
    let selectedLender = mortgageLender.text
    let selectedTerm = mortgageTerm.text


        let matchedLender = Data.currentRateData.first(where: {$0.financialInstitution == selectedLender})

        let sixMonthRate = matchedLender?.sixMonths
        let oneYearRate = matchedLender?.oneYear
        let twoYearRate = matchedLender?.twoYear
        let threeYearRate = matchedLender?.threeYear
        let fourYearRate = matchedLender?.fourYear
        let fiveYearRate = matchedLender?.fiveYear

        DispatchQueue.main.async {

        var selectedRateString:String = "0"

        if selectedTerm == "sixMonths" {
            let selectedRate = sixMonthRate
            selectedRateString = selectedRate ?? "0"
        } else if selectedTerm == "1 Year" {
            let selectedRate = oneYearRate
            selectedRateString = selectedRate ?? "0"
        } else if selectedTerm == "2 Year"{
            let selectedRate = twoYearRate
            selectedRateString = selectedRate ?? "0"
        } else if selectedTerm == "3 Year" {
            let selectedRate = threeYearRate
            selectedRateString = selectedRate ?? "0"
        }else if selectedTerm == "4 Year" {
            let selectedRate = fourYearRate
            selectedRateString = selectedRate ?? "0"
        }else if selectedTerm == "5 Year" {
            let selectedRate = fiveYearRate
            selectedRateString = selectedRate ?? "0"
        }

         self.mortgageInterestRate.text = selectedRateString.percentage
    }
    func textField(_ textField: UITextField, shouldChangeCharactersIn 
    range: NSRange, replacementString string: String) -> Bool {


    if textField.text == mortgageInterestRate.text {

        let text: NSString = (textField.text ?? "") as NSString
        let finalString = text.replacingCharacters(in: range, with: 
        string)
        mortgageInterestRate.text = finalString.percentage

        return false

    }
}

    var percentage: String {
    // removing all characters from string before formatting
    let stringWithoutSymbol = self.replacingOccurrences(of: "%", with: 
     "")

    let styler = NumberFormatter()
    styler.minimumFractionDigits = 2
    styler.maximumFractionDigits = 2
    styler.numberStyle = .percent
    styler.multiplier = 1

    if let result = NumberFormatter().number(from: stringWithoutSymbol) 
 {
        return styler.string(from: result)!
    }

    return self
}

标签： swiftuitextfield