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（例如“ 1.0”和“ 1”），应用程序崩溃，结果应用程序崩溃是因为't减去Int和Double，以确保我想限制用户只能输入十进制数字“ 1.0”。对我而言，最好的方法是编写如下代码：如果用户在按下完成按钮后自动输入“ 1”，然后添加“ .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HERE中的此方法

Tgt_df_time_in_zone_detail = Tgt_df_view_time_in_zone_detail_dtaas.join(Tgt_df_individual_in_shift_tiz,
(Tgt_df_view_time_in_zone_detail_dtaas.id_individual == Tgt_df_individual_in_shift_tiz.id_individual)
& (Tgt_df_view_time_in_zone_detail_dtaas.timestamp_start >= Tgt_df_individual_in_shift_tiz.swipein)
& (Tgt_df_view_time_in_zone_detail_dtaas.timestamp_start <= Tgt_df_individual_in_shift_tiz.swipeout)
& (Tgt_df_view_time_in_zone_detail_dtaas.timestamp_end >= Tgt_df_individual_in_shift_tiz.swipein) 
& (Tgt_df_view_time_in_zone_detail_dtaas.timestamp_end <= Tgt_df_individual_in_shift_tiz.swipeout)
, "left_outer")

然后在完成按钮的操作中添加以下内容：

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
}

当您输入@IBAction func btnDoneTapped(_ sender: Any) { print(tf.text) guard let obj = Double(tf.text!) else { return } print(obj) }并按完成按钮时，1将打印print(tf.text)，而Optional("1")将打印print(obj)

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？

2 个答案: