Android Google Maps API V2 gets slower each time it loads again

Question

I have a fragment in my app which has a MapFragment inside. When I load this fragment I start to read about 2000 marker data from server and after reading them I will loop through each marker and add it to the Map. At first it takes 4 seconds for the map to show these 2000 markers. but each time after loading the map again ( like changing orientation or changing the drawermenu item and backing to the map again ) it takes more and more to load the markers. for example after 8 times changing the orientation, it takes 40 seconds for the map to load the same 2000 markers !

here is how I initialize the map :

        googleMap = ((MapFragment) getFragmentManager().findFragmentById(R.id.map)).getMap();
        CameraPosition cameraPosition = new CameraPosition.Builder().target( new LatLng(50.941303, 6.958166)).zoom(10).build();
        googleMap.moveCamera(CameraUpdateFactory.newCameraPosition(cameraPosition));

        // check if map is created successfully or not
        if (googleMap == null) {
            Toast.makeText(getActivity().getApplicationContext(),
                    "Sorry! unable to create maps", Toast.LENGTH_SHORT)
                    .show();
        }

and here I add the markers to the map :

    for (int i = 0; i<mapVehicles.size(); i++)
    {
        // latitude and longitude
        double latitude = mapVehicles.get(i).latitude;
        double longitude = mapVehicles.get(i).longitude;

        // create marker
        MarkerOptions marker = new MarkerOptions().position(new LatLng(latitude, longitude))
                .title(mapVehicles.get(i).lineTripIdentification).snippet(destinationShort + ": " + mapVehicles.get(i).destination);

        // Changing marker icon
        marker.icon(BitmapDescriptorFactory.fromResource(R.drawable.vehicleannotation));

        // adding marker            
        vehicleMarkers.put(googleMap.addMarker(marker), mapVehicles.get(i));


    }

I also used the following in the onCreateView of the Fragment which has the MapFragment :

this.setRetainInstance(true);

any help would be much appreciated :)

Answer 1

Instead of removing and adding all markers again and again you should change the position of each marker by setPosition (LatLng latlng).

Answer 2

Only load the markes if not loaded before:

public void onCreate(Bundle savedInstanceState) {

    ...

    if (savedInstanceState != null) {
        // do nothing 
    } else {
        // add markers
    }

}