public void onShow() {
map.clearOverlays();
// Add 10 markers to the map at random locations
LatLngBounds bounds = map.getBounds();
LatLng southWest = bounds.getSouthWest();
LatLng northEast = bounds.getNorthEast();
double lngSpan = northEast.getLongitude() - southWest.getLongitude();
double latSpan = northEast.getLatitude() - southWest.getLatitude();
for (int i = 0; i < 10; i++) {
LatLng point = LatLng.newInstance(southWest.getLatitude() + latSpan
* Math.random(), southWest.getLongitude() + lngSpan * Math.random());
map.addOverlay(createMarker(point, i));
}
}