code: public static MapsForgeTileSource createFromFiles(File[] file, XmlRenderTheme theme, String themeName) {
          //these settings are ignored and are set based on .map file info
          int minZoomLevel = MIN_ZOOM;
          int maxZoomLevel = MAX_ZOOM;
          int tileSizePixels = TILE_SIZE_PIXELS;
  
          return new MapsForgeTileSource(themeName, minZoomLevel, maxZoomLevel, tileSizePixels, file, theme, MultiMapDataStore.DataPolicy.RETURN_ALL, null);
      }
docs: Creates a new MapsForgeTileSource from file[].
  <p></p>
  Parameters minZoom and maxZoom are obtained from the
  database. If they cannot be obtained from the DB, the default values as
  defined by this class are used, which is zoom = 3-20
  
  @param file
  @param theme     this can be null, in which case the default them will be used
  @param themeName when using a custom theme, this sets up the osmdroid caching correctly
  @return