title: How to get the Map Extent change event in OSMdroid?
body: <p>I am using the Osmdroid library in my custom Android App. </p>
  
  <p>At every extent change (&amp; when the map is zoomed in) I want to query the sqlite database and get records that lie within that extent. For this I need something similar to a Map Extent change event.</p>
  
  <p>I could not find such an event on the MapView Class. How Do I achieve what I want to do? </p>
  
  <p><strong>UPDATE</strong>
  I am using the MapListner like this:</p>
  
  <pre><code>mapView.setMapListener(new MapListener() {   
      public boolean onZoom(ZoomEvent arg0) {
          return false;
      }
  
      public boolean onScroll(ScrollEvent arg0) {
           onExtentChange();
          return false;
      }
  } );
  </code></pre>
  
  <p>but the onScrollEvnt is fired several times for each pan of the map. How do I get the last or final scrollEvent?</p>