Swift 3 - Limit TextField to alphanumeric (with whitespace and hypens) - swift

Question

Want to limit Textfield input to only A-Z,a-z,0-9, " " and -. Currently have:
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool
{
if self.isNumericTextInput{
let allowedCharacters = CharacterSet.decimalDigits
let characterSet = CharacterSet(charactersIn: string)
if allowedCharacters.isSuperset(of: characterSet) && returnFlag{
return true
} else{
return false
}
} else{
// Allow only alphanumerics, whitespace and hyphens
}
return
}

Answer 1

Though it's late to answer, but it might be useful to someone.
Swift 3:
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
/// 1. replacementString is NOT empty means we are entering text or pasting text: perform the logic
/// 2. replacementString is empty means we are deleting text: return true
if string.characters.count > 0 {
var allowedCharacters = CharacterSet.alphanumerics
allowedCharacters.insert(charactersIn: " -") // "white space & hyphen"
let unwantedStr = string.trimmingCharacters(in: allowedCharacters)
return unwantedStr.characters.count == 0
}
return true
}
Note: This will work for pasting strings into the text field as well. Pasted string will not be displayed in text field if it contains any unwanted characters.

Answer 2

Try this:
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
let characterSet = CharacterSet(charactersIn: string)
let allowedCharacters = (self.isNumericTextInput
? CharacterSet.decimalDigits
: CharacterSet(charactersIn: "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789 -"))
return allowedCharacters.isSuperset(of: characterSet) && returnFlag
}