Android：Osmdroid在触摸上添加标记不准确

Question

I tried to add marker when mapview touched based on this question , this is my code

    GeoPoint geoPoint = new GeoPoint(mLatitude, mLongitude);
    IMapController mapController = mMapView.getController();
    mapController.setZoom(5);
    mapController.setCenter(geoPoint);

    Overlay overlay = new Overlay(getActivity()) {

        ItemizedIconOverlay<OverlayItem> items = null;

        @Override
        protected void draw(Canvas c, MapView osmv, boolean shadow) {

        }

        @Override
        public boolean onSingleTapConfirmed(MotionEvent e, MapView mapView) {
            Projection proj = mapView.getProjection();
            GeoPoint loc = (GeoPoint) proj.fromPixels((int)e.getX(), (int)e.getY());
            double longitude = loc.getLongitudeE6()/1000000;
            double latitude = loc.getLatitudeE6()/1000000;

            mLatitude = latitude;
            mLongitude = longitude;

            ArrayList<OverlayItem> markers = new ArrayList<>();
            OverlayItem item = new OverlayItem("", "", new GeoPoint(latitude, longitude));
            item.setMarker(ContextCompat.getDrawable(getActivity(), R.drawable.ic_maps_marker_large));
            markers.add(item);

            if (items == null) {
                items = new ItemizedIconOverlay<>(getActivity(), markers, null);
                mMapView.getOverlays().add(items);
                mMapView.invalidate();
            } else {
                mMapView.getOverlays().remove(items);
                mMapView.invalidate();
                items = new ItemizedIconOverlay<>(getActivity(), markers, null);
                mMapView.getOverlays().add(items);
            }
            return true;
        }

    };

    mMapView.getOverlays().add(overlay);

The problem is when zoomed in marker added on random position, not accurate. But it's working fine if mapview zoomed out, maybe about 5 zoom level and below.

Answer 1

(Posted on behalf of the OP).

Finally I'm able to fix this by using this code:

    GeoPoint geoPoint = new GeoPoint(mLatitude, mLongitude);
    IMapController mapController = mMapView.getController();
    mapController.setZoom(5);
    mapController.setCenter(geoPoint);

    Overlay overlay = new Overlay(getActivity()) {

        ItemizedIconOverlay<OverlayItem> items = null;

        @Override
        protected void draw(Canvas c, MapView osmv, boolean shadow) {

        }

        @Override
        public boolean onSingleTapConfirmed(MotionEvent e, MapView mapView) {
            Projection proj = mapView.getProjection();
            GeoPoint loc = (GeoPoint) proj.fromPixels((int)e.getX(), (int)e.getY());
            double longitude = loc.getLongitude();
            double latitude = loc.getLatitude();
            mLatitude = latitude;
            mLongitude = longitude;

            ArrayList<OverlayItem> markers = new ArrayList<>();
            OverlayItem item = new OverlayItem("", "", new GeoPoint(latitude, longitude));
            item.setMarker(ContextCompat.getDrawable(getActivity(), R.drawable.ic_maps_marker_large));
            markers.add(item);

            if (items == null) {
                items = new ItemizedIconOverlay<>(getActivity(), markers, null);
                mMapView.getOverlays().add(items);
                mMapView.invalidate();
            } else {
                mMapView.getOverlays().remove(items);
                mMapView.invalidate();
                items = new ItemizedIconOverlay<>(getActivity(), markers, null);
                mMapView.getOverlays().add(items);
            }
            return true;
        }

    };

    mMapView.getOverlays().add(overlay);