如何使用swift3.0在uitextfield中设置最大4位数字

Question

我使用此代码，但 return 任何人都应该使用。但是我需要使用这两种情况。那么我该如何改变呢？任何人帮助我。我限制了一个 (.0 符号，同时只允许 4 位数。我该怎么做。？？？

   func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {

    guard let text = amountField.text else { return true }
    let newLength = text.characters.count + string.characters.count - range.length
    return newLength <= 4 // Bool

   let ACCEPTABLE_CHARACTERS = "1234567890"
    let cs = CharacterSet(charactersIn: ACCEPTABLE_CHARACTERS).inverted
    let filtered: String = string.components(separatedBy: cs).joined(separator: "")
    return string == filtered



}

Answer 1

您的问题的可能解决方案。

func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {

    var newLength = string.utf16.count - range.length

    if let text = textfield.text {
        newLength = text.utf16.count + string.utf16.count - range.length
    }

    let characterSet = NSMutableCharacterSet()
    characterSet.addCharacters(in: "1234567890")

    if string.rangeOfCharacter(from: characterSet.inverted) != nil || newLength > 4 {
        return false
    }
    return true
}

如何使用swift3.0在uitextfield中设置最大4位数字

how to set the maximum 4 digit number in uitextfield using swift3.0

uitextfield

swift3

swift4