ros_android map_nav add layer errors

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While I was trying to build map_nav, I noticed that add layer part has several errors.

As I touched mini view at upper right side (the occupancy layer preview), the map just disappears

and only arrows and paths appears.

I tried to fix this problem by loading separate "main activity" and two layouts.

Initially, the map appears in large scale and camera view appears in small scale (first layout, swaped view in xml file).

If I touch the camera preview at upper right side, MainActivity is loaded again with different layout (the one that is in git hub, camera view in larger scale and map in smaller scale).

This method succeeded in loading map, however, the arrow and paths did not appear.

If I press the map for a long time, arrows and paths appears and simultaneously, another arrow appears at the position I long pressed but map still disappears.

Does anyone has solution to original problem or to my solution?

Also, can anyone explain which activity draws arrows and lines?

            mapView.addLayer(occupancyGridLayer);
    mapView.addLayer(laserScanLayer);
    mapView.addLayer(pathLayer);
    mapView.addLayer(mapPosePublisherLayer);
    mapView.addLayer(initialPoseSubscriberLayer);
    mapView.addLayer(viewControlLayer)

I do get that occupancyGridLayer is the map view, however, I still cannot figure out which activity draws arrows, lines and goal arrow and such...

Thank you.