How to prepare a map tiles archive for osmdroid for offline maps?

Question

I prepared this simple project to test the offline map functionality of osmdroid. In the first step I use the Internet connection to download tiles. Everything works as expected. The following code snippet shows the settings for the activity containing the map view.

public class MainActivity extends Activity {

    public static final GeoPoint BERLIN = new GeoPoint(52.516667, 13.383333);

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        MapView mapView = (MapView) findViewById(R.id.mapview);
        mapView.setClickable(true);
        mapView.setBuiltInZoomControls(true);
        mapView.setMultiTouchControls(true);
        mapView.setUseDataConnection(true);
        mapView.setTileSource(TileSourceFactory.MAPNIK);

        IMapController mapViewController = mapView.getController();
        mapViewController.setZoom(15);
        mapViewController.setCenter(BERLIN);
    }

}

Now I want to manually supply a archive file containing the tile bitmaps. These are the steps I did to prepare for offline mode:

1. I zip the existing folders on the sdcard which can be found in /mnt/sdcard/osmdroid/tiles/.
2. I place the resulting Mapnik.zip one level above in /mnt/sdcard/osmdroid/.
3. I delete all the cached tiles in /mnt/sdcard/osmdroid/tiles/Mapnik.

Now I turn off the wireless connection on the phone and restart the application. No map tile shows up. Why?

Answer 1

You're supposed to use the tile packager to create your zip, or mobile atlas creator. However, if you rename all the *.tile files in your zip to *.png, it should work (not tested).