mapView getItemsAtLocation nullPointerException

 The error was arising when there was an itemizedoverlay, which had no overlayitems, on the mapview. The following code solved the error:

if(itemizedoverlayCurrent.hasItems()) overlays.add(itemizedoverlayCurrent); 
if(itemizedoverlayCompleted.hasItems())overlays.add(itemizedoverlayCompleted);  
if(itemizedoverlayFuture.hasItems())overlays.add(itemizedoverlayFuture);