Question

我已经在其上创建了一个带有UITextField的UIAlertController，并且UITextField只需要在0到100之间取整数。

我该怎么做？

这是我的代码

let confirm = UIAlertController(title: "I want to reserve", message: "sometext", preferredStyle: UIAlertControllerStyle.alert)

            confirm.addTextField(configurationHandler: { (textField) in


                textField.placeholder = "Please fill the number between 0-100"

            })

            confirm.addAction(UIAlertAction(title: "No", style: UIAlertActionStyle.default, handler: nil))

            confirm.addAction(UIAlertAction(title: "Yes", style: UIAlertActionStyle.destructive, handler: { (action) in

                self.isReserve = true

                self.reservedIcon.alpha = 0
                self.reservedTitle.alpha = 0

                self.cancelReservedIcon.alpha = 1
                self.cancelReservedTitle.alpha = 1


            }))

Answer 1

let confirm = UIAlertController(title: "I want to reserve", message: "sometext", preferredStyle: UIAlertControllerStyle.alert)

        confirm.addTextField(configurationHandler: { (textField) in


            textField.placeholder = "Please fill the number between 0-100"

        })

        confirm.addAction(UIAlertAction(title: "No", style: UIAlertActionStyle.default, handler: nil))

        confirm.addAction(UIAlertAction(title: "Yes", style: .default, handler: { [weak alert] (_) in
        let textField = alert?.textFields![0]
        if textField.text != "1234" {  // change your if condition
           self.isReserve = true

            self.reservedIcon.alpha = 0
            self.reservedTitle.alpha = 0

            self.cancelReservedIcon.alpha = 1
            self.cancelReservedTitle.alpha = 1
        } else {
           // your else condition
        }
}))

Answer 2

将UITextFieldDelegate添加到您的控制器

然后你的代码：

    let confirm = UIAlertController(title: "I want to reserve", message: "sometext", preferredStyle: UIAlertControllerStyle.alert)

        confirm.addTextField(configurationHandler: { (textField) in


            textField.placeholder = "Please fill the number between 0-100"

        })
        let textfield = confirm.textFields?.first
        textfield?.keyboardType = .numberPad
        textfield?.delegate = self
        confirm.addAction(UIAlertAction(title: "No", style: UIAlertActionStyle.default, handler: nil))

        confirm.addAction(UIAlertAction(title: "Yes", style: UIAlertActionStyle.destructive, handler: { (action) in

            self.isReserve = true

            self.reservedIcon.alpha = 0
            self.reservedTitle.alpha = 0

            self.cancelReservedIcon.alpha = 1
            self.cancelReservedTitle.alpha = 1


        }))

        self.present(confirm, animated: true) {

        }

添加Textfield委托：

func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
    guard let text = textField.text else { return true }
    return text.characters.count <= 100 // Your limit
}

Answer 3

您可以使用shouldChangeCharactersInRange方法和String扩展来检查输入字符串是否包含数字并控制0到100之间的文本输入

    extension String  {
        var isNumber : Bool {
            get{
                return !self.isEmpty && self.stringWithoutWhitespaces.rangeOfCharacter(from: CharacterSet.decimalDigits.inverted) == nil
            }
        }

        var stringWithoutWhitespaces: String {
            return self.replacingOccurrences(of: " ", with: "")
        }

     }


    func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
        // return true if the string only contains numeric characters
        var isValid = false
        if string.isNumber {
            if let num = Int(string.stringWithoutWhitespaces) {
                isValid = (num >= 0 && num <= 100)
            }
        }
        return isValid
     }

如何在UIAlertController上限制UITextField只使用指定范围的数字？

3 个答案: