title: How to update markers on the MapView?
body: <p>I've added a few markers to my MapView:</p>
  
  <pre><code>List&lt;Overlay&gt; mapOverlays;
  Drawable drawable;
  MapOverlay itemizedOverlay;
  
  mapOverlays = mapView.getOverlays();
  drawable = this.getResources().getDrawable(R.drawable.map_dot_green);
  itemizedOverlay = new MapOverlay(drawable, mapView);
  GeoPoint markerPoint = new GeoPoint(lat, lng);
  OverlayItem overlayItem = new OverlayItem(markerPoint, "name", "description");
  itemizedOverlay.addOverlay(overlayItem);
  mapOverlays.add(itemizedOverlay);
  </code></pre>
  
  <p>Now I need to change markers (<code>drawables</code>) regularly for them. I am planning to use <code>Runnable</code> for this. But how can I replace the markers?</p>
  
  <p>Upd. here is the current code for the same:</p>
  
  <pre><code>public class Map extends MapActivity {
      private MapOverlay itemizedOverlay;
      private MapView mapView;
  
  private Runnable mUpdateMapMarkers = new Runnable() {
       public void run() {
         Drawable drawable_green = getResources().getDrawable(R.drawable.map_dot_green);
         int w = drawable_green.getIntrinsicWidth();
         int h = drawable_green.getIntrinsicHeight();
         drawable_green.setBounds(-w / 2, -h, w / 2, 0);
  
         for (int i = 0; i &lt; itemizedOverlay.size(); i++) {
           itemizedOverlay.getItem(i).setMarker(drawable_green);
         }
         mapView.invalidate();
  
           mHandler.postDelayed(mUpdateMapMarkers, 5*60*1000); // once in 5 minutes   
       }
    };
  </code></pre>