How to prevent users from entering '#' and empty space(' ') in UITextfield - swift?

Question

I am trying to prevent users from entering the characters '#' and empty spaces (' '). I have got as far as below (see code below) but not sure how to complete the rest ...

 class CreateTags: UIViewController, UITextFieldDelegate {

 /*** OUTLETS ***/
 @IBOutlet weak var inputTxtOutlet: UITextField!


 override func viewDidLoad() {
      self.inputTxtOutlet.delegate = self
 }

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

 }

Answer 1

You need o implement following delegate method (as you already implemented)

Set delegate

yourtextField.delegate = self

Delegate method

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

    if string == "#" || string == " " {
        return false //disallow # and a space
    }
    return true

 }

In another way you can do it as follow

Create a constant that contains disallowed chars.

 let disallowedChars = ["#", " "] //add more chars as per your need

In delegate method check those chars...

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

      if disallowedChars.contains(string) {
        return false
      }

      return true
}