title: Mapview osmdroid not visible in a fragment
body: <p>I've tried to add the MapView (org.osmdroid.views.MapView) in a relativeLayout in the Fragment's onActivityCreated. But it don't work. This Fragment is launched by a ShrlockFragmentActivity.
  How Can I make it work?</p>
  
  <pre><code>public class CommuneFragment extends SherlockFragment {
  
  Context mContext = getActivity();
  
  public void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setHasOptionsMenu(true);
  }
  
  public View onCreateView(LayoutInflater inflater, ViewGroup container,
          Bundle savedInstanceState) {
      super.onCreateView(inflater, container, savedInstanceState) ;
      return inflater.inflate(R.layout.commune_map_fragment, container, false);
  }
  
  
  @Override
  public void onActivityCreated(final Bundle savedState) {
      super.onActivityCreated(savedState);
      mContext=getActivity();
  
      View mView = getView();
  
      //Create the OSM view
      MapView mapView = new MapView(mContext, null);
      //enable zoom in and out on the OSM
      mapView.setClickable(true);
      mapView.setBuiltInZoomControls(true);
  
      RelativeLayout RL= (RelativeLayout) getActivity().findViewById(R.id.rl);
      RL.addView(mapView);
    }
  </code></pre>