元组Void（aka（））的值没有成员＆＃34; isSuperset＆＃34;

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＆＃34; both.isSuperset（of：characterSet as CharacterSet）＆＃34;。怎么纠正？

更新1： 使用当前建议的答案显示错误

更新2： 最近更新

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，使“allowed”（或“both”，无论你决定命名它）在viewDidLoad中创建的属性，这样你就不会重新创建和联合每次输入字符时都会设置字符集。