Detect backspace Event in UITextField

Question

I am searching for solutions on how to capture a backspace event, most Stack Overflow answers are in Objective-C but I need on Swift language.

First I have set deleg

Answer 1

Swift 4: If the user presses the backspace button, string is empty so this approach forces textField to only accept characters from a specified character set (in this case utf8 characters) and backspaces (string.isEmpty case).

func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
    if string.cString(using: String.Encoding.utf8) != nil {
        return true
    } else if string.isEmpty {
        return true
    } else {
        return false
    }
}