Android：Osmdroid 在触摸时添加标记不准确

Posted 2023-03-25

【中文标题】Android：Osmdroid 在触摸时添加标记不准确

【英文标题】：Android: Osmdroid add marker on touch not accurate

【发布时间】：2016-05-29 17:05:45

【问题描述】：

我尝试在基于此question 触摸地图视图时添加标记，这是我的代码

    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);

问题是在随机位置上添加的标记放大时，不准确。但是，如果 mapview 缩小它就可以正常工作，可能是大约 5 级及以下。

【参考方案1】：

（代表 OP 发布）。

最后我可以通过使用这段代码来解决这个问题：

    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);