如何限制文本字段只能输入十进制数字？

Question

我有用于 Celectial 导航计算的应用程序，我已将代码 textField.text 转换为 Double，但有时如果用户输入某些字段（如“1.0”和“1”），应用程序会崩溃，结果应用程序崩溃，因为无法扣除 Int 和 Double，以确保我想限制用户仅输入十进制数字“1.0”。对我来说最好的方法是编写一些代码，如果用户在按下完成按钮后自动输入例如“1”，添加“.0”以获得 1.0?

func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
    let allowedCharacters = "-1234567890."
        let allowedCharacterSet = CharacterSet(charactersIn: allowedCharacters)
        let typedCharactersSet = CharacterSet(charactersIn: string)
        return allowedCharacterSet.isSuperset(of: typedCharactersSet)

    }




     func TextField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
        guard let text = latDegTextField.text else { return true }
        let count = text.count + string.count - range.length
        return count == 2
    }

Answer 1

首先使用中的这个方法，即

func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
    if textField.text != "" || string != "" {
        let res = (textField.text ?? "") + string
        return Double(res) != nil
    }
    return true
}

然后在完成按钮操作中添加：

@IBAction func btnDoneTapped(_ sender: Any) {

    print(tf.text)
    guard let obj = Double(tf.text!) else { return }
    print(obj)
}

并且当您输入 1 并按下完成按钮时 print(tf.text) 将打印 Optional("1") 而 print(obj) 将打印 1.0

Answer 2

使用此代码：-

func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
        //Will prevent user from entering space as first character
        let enteredCharString = "\(textField.text ?? "")\(string )"
        if enteredCharString.trimmingCharacters(in: .whitespaces).count == 0 {
            return false
        }
        switch textField {
        case txt_Ammount:
            if txt_Ammount.text != "" || string != "" {
                let res = (txt_Ammount.text ?? "") + string
                return Double(res) != nil
            }
        default:
            true
        }



        return true

    }

如何限制文本字段只能输入十进制数字？

How to limit the text field to be able to enter only decimal digits?

validation

decimal

uitextfield

ios

swift