我想使用货币格式化程序来设置带有逗号的金额和带有限制的小数，字符也不应超过 10，$ 应首先出现

Question

我想使用货币格式化程序来设置带逗号的金额和带限制的小数，字符也不应超过 10，$ 应首先出现。代码示例如下，但不适用于十进制。

    func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
        var newLength = 10
        if textField == donateAmountTextfield {
                let text = donateAmountTextfield.text!
                newLength = text.characters.count + string.characters.count - range.length
        }
    return newLength <= 10 // Bool
}
func textFieldDidEndEditing(_ textField: UITextField) {
    if textField == donateAmountTextfield {
        if donateAmountTextfield.text != "" {
            dollerSign.isHidden = true
            if let amountString = donateAmountTextfield.text?.currencyInputFormatting() {
                donateAmountTextfield.text = amountString
            }
    } else {
            dollerSign.isHidden = false
        }
    } else if textField == enterCardNumber {
        if validateData.validateDonation((donateAmountTextfield?.text)! as String) {
            self.view.makeToast("Please enter valid Donation amount", duration: 5.0, position: CSToastPositionCenter)
        }
    }
}

格式化程序类-

extension String {
    // formatting text for currency textField
    func currencyInputFormatting() -> String {
        var number: NSNumber!
        let formatter = NumberFormatter()
        formatter.numberStyle = .currencyAccounting
        formatter.currencySymbol = "$"
        formatter.maximumFractionDigits = 2
        formatter.minimumFractionDigits = 2
        var amountWithPrefix = self
        // remove from String: "$", ".", ","
        let regex = try! NSRegularExpression(pattern: "[^0-9]", options: .caseInsensitive)
        amountWithPrefix = regex.stringByReplacingMatches(in: amountWithPrefix, options: NSRegularExpression.MatchingOptions(rawValue: 0), range: NSMakeRange(0, self.characters.count), withTemplate: "")
        let double = (amountWithPrefix as NSString).doubleValue
        number = NSNumber(value: (double / 1))
        // if first number is 0 or all numbers were deleted
        guard number != 0 as NSNumber else {
            return ""
        }
        return formatter.string(from: number)!
    }
}

Answer 1

IBtextFieldName.text = self.formatCurrency(strAmount: strAmount) //In viewDidLoad
func formatCurrency(strAmount strAmount: String) -> String  {
    let formatter = NSNumberFormatter()
    formatter.numberStyle = NSNumberFormatterStyle.CurrencyStyle
    formatter.locale = NSLocale(localeIdentifier: "en_US")
    let numberFromField = (NSString(string: strAmount).doubleValue)/100
    return formatter.stringFromNumber(numberFromField)!
}
//For character should not exceed by 10
func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
    let newCharLength = textField.text!.characters.count + string.characters.count - range.length
    if newCharLength >= 10 {
        return false
    }
}