title: Android: application-wide font-size preference
body: <p>Is it possible to make an application-wide setting for the font-size to be used by all views displaying text? 
  I would like to provide a Preference to the user which should allow scaling all text in the app.</p>
  
  <p>Android explicitly allows using the <a href="http://developer.android.com/guide/topics/resources/more-resources.html#Dimension" rel="noreferrer">"sp" dimension unit</a> for scalable text, however there is no actual way to set the "user's font size preference" in a global way.</p>
  
  <p>Iterating through all views on Activity instantiation is not really an option ;-)</p>