title: adding multiple marker on google map in android
body: <p>I am triyng to add multiple marker on google map. Here is my  code section</p>
  
  <pre><code>public class GoogleMap extends MapView 
   {
       MapController mc;
       MapView mapView; 
       GeoPoint p; 
  
      @Override
      public void onCreate(Bundle savedInstanceState)
      {
      ....
  
           double lat = Double.parseDouble(bundle.getString("paramLat"));
           double lng = Double.parseDouble(bundle.getString("paramLong"));
  
           mc = mapView.getController();
           p = new GeoPoint( (int) (lat * 1E6),  (int) (lng * 1E6));
           mc.animateTo(p);
           mc.setZoom(17);
  
           //---Add a location marker---
           MapOverlay mapOverlay = new MapOverlay();
           List&lt;Overlay&gt; listOfOverlays = mapView.getOverlays();
           listOfOverlays.clear();
           listOfOverlays.add(mapOverlay);    
  
           mapView.invalidate();
    }
  
  
  
  
  class MapOverlay extends com.google.android.maps.Overlay
      {
  
           @Override
           public boolean draw(Canvas canvas, MapView mapView, boolean shadow, long when) 
           {
              super.draw(canvas, mapView, shadow);       
  
  
                  //---translate the GeoPoint to screen pixels---
                      Point screenPts = new Point();
                      mapView.getProjection().toPixels(p, screenPts);
  
                     //---add the marker---
                     Bitmap bmp = BitmapFactory.decodeResource(getResources(),  R.drawable.pushpin);            
                     canvas.drawBitmap(bmp, screenPts.x, screenPts.y-50, null);     
  
  
                     return true;
  
  
  
           }
  }
  </code></pre>
  
  <p>I have two question here. When i tried to add only one marker, it works but draw method is invoked many times. But why? and when is it invoked? </p>
  
  <p>The second question is how can i add new marker. I created second geoPoint named p2 and after that what should i do? Thank you very much.</p>