title: Codename One - Listener for virtual keyboard opened and virtual keyboard closed
body: <p>I would like to execute some code when the virtual keyboard (if it exists) it's opened and when it's closed. I'm not interested for a listener attached to a particular text field, I'm interested to execute some code every time that the virtual keyboard is opened and is closed.</p>
  
  <p>For example, can I log when it's opened and when it's closed?</p>
  
  <p>I've seen the method <code>getVirtualKeyboardListener()</code> of the class <code>Display</code>, but I didn't understood how to use it.</p>