title: Put indeterminate ProgressBar inside of PreferenceFragment's ListPreference
body: <p>How could I put a 'spinning' progress bar inside of a listpreference layout? It starts with an empty content (in fact there should only be the progressbar) and once the list content is processed the spinbar should be replaced by my content.</p>
  
  <p>How can I implement this through XML?</p>
  
  <p>Thank you in advance.</p>