title: iOS keyboard delegate callback function
body: <p>I've got a function set up to run when the return key is tapped on an textfield keypad, in an iOS app I'm writing.</p>
  
  <p>The function is quite slow, and takes about 15 - 20 seconds to run, during which time the whole screen just freezes up, the keypad hangs on the screen and nothing happens.</p>
  
  <p>Only when the function finishes running does the keypad disappear.</p>
  
  <p>The XIB file has "Editing Did End" set to "searchPlates", the funciton name, and it all works fine, I just want the keyboard to disappear, so I can show a UIProgressView while the search is happening. </p>
  
  <p>I've also got the following code in the view controller:</p>
  
  <pre><code>-(BOOL)textFieldShouldReturn:(UITextField *)thisTextField {
      if (thisTextField == self.plateInput) {
          [thisTextField resignFirstResponder];
      }
      return YES;
  } 
  </code></pre>
  
  <p>Is that clear enough? I want the keypad to disappear straight away when searchPlates is called.</p>