title: osmdroid - how to download tiles for offline use?
body: <p>My app tries to download tiles for offline use like this:</p>
  
  <pre><code>for (MapTile mapTile : tileSet) {   
    mapView.getTileProvider().getMapTile(mapTile);
  }
  </code></pre>
  
  <p>However, only a small part of the tileSet is actually downloaded.</p>
  
  <p>How can I download all tiles contained in the tileSet at once?</p>