title: UISearchbar keyboard search button Action
body: <p>I'm using <code>UISearchBar</code> when I input text on <code>UISearchBar</code> the keyboard shows. At that time, keyboard return key is "Search".
  I want to implement event when I press the keyboard search button.
  How can I implement the action?
  On <code>UITextField</code> it has </p>
  
  <pre><code>-(BOOL)textFieldShouldReturn:(UITextField *)textField;
  </code></pre>
  
  <p>But on <code>UISearchBar</code> it doesn't have return action.</p>
  
  <p>Thank you for your helping.</p>