2021-08-13

限制输入框只能输入两位小数

限制输入框只能输入两位小数，如果一开始输入0，然后再次输入数字。默认在中间给添加上小数点。

    /// 输入框限制数字
    func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
        let text = textField.text ?? ""
        if !Tool.isNumberAndTwoDecimalContent(string: text + string) {
            if text.count > 0, string == ".", !text.contains(".") {
                return true
            }
            return false
            
        } else {
            if textField.text == "0", Tool.isNumberContent(string: string) {
                textField.text = "0."
            }
        }
        return true
    }

    /**
     *   判断只能输入数字和小数点后两位
     */
    static func isNumberAndTwoDecimalContent(string:String) -> Bool {
        let regex = "^[0-9]+(\\.[0-9]{1,2})?$"
        let predicate = NSPredicate(format: "SELF MATCHES %@", regex)
        let isValid = predicate.evaluate(with: string)
        return (isValid ? true : false)
    }

    /**
     *   判断只能输入数字
     */
    static func isNumberContent(string:String) -> Bool {
        let scan: Scanner = Scanner(string: string)
        var val:Int = 0
        return scan.scanInt(&val) && scan.isAtEnd
    }