swift - 元组 Void (aka ()) 的值没有成员 "isSuperset"

Question

我在两个字符集之间创建了一个联合，以便能够使用带有 decimalDigits 字符集的句点。

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

            let allowed = CharacterSet.decimalDigits
            let period = CharacterSet.init(charactersIn: ".")
            let both = CFCharacterSetUnion(allowed as! CFMutableCharacterSet, period as CFCharacterSet)

            let characterSet = NSCharacterSet(charactersIn: string)

            return both.isSuperset(of: characterSet as CharacterSet)
        }

然而，返回“both.isSuperset(of: characterSet as CharacterSet)”。如何纠正？

更新 1:与当前建议的答案一起显示的错误

更新 2:最新更新

Answer 1

尝试这样做:

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

    var allowed = CharacterSet.decimalDigits
    let period = CharacterSet.init(charactersIn: ".")
    allowed.formUnion(period)

    //UNCOMMENT when isSuperset is working
    //let characterSet = CharacterSet(charactersIn: string)
    //return allowed.isSuperset(of: characterSet)

    // Swift 3 appropriate solution 
    let isSuperset = string.rangeOfCharacter(from: allowed.inverted) == nil
    return isSuperset
}

I found here的基础.

更好的是，让“allowed”(或“both”，无论您决定如何命名)成为在 viewDidLoad 中创建的属性> 这样您就不会在每次键入字符时都重新创建和合并字符集。