title: UITextFieldDelegate method not called
body: <p>I'm following the Big Nerd Ranch iOS Programming book (Swift version) and I have this file.</p>
  
  <pre><code>import UIKit
  
  class ConversionViewController: UIViewController, UITextFieldDelegate {
  
      @IBOutlet var celsiusLabel: UILabel!
      @IBOutlet var textField: UITextField!
  
      func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -&gt; Bool {
          print("here")
          return true
      }
  
      //rest of the code here
  }
  </code></pre>
  
  <p>For some reason, the textField delegate method is not called. I can't see the "here" log in my console. I have double checked the naming and syntax a lot of times. Any ideas?</p>