在地图上绘制多个多边形

Question

I am facing this simple yet annoying problem in developing an App on AndroidStudio. I need to make my app able to draw more than one polygon on map.

You need to know that: 1. I don't want to have a fixed number of polygon's vertex. 2. I don't want to have a fixed number of polygons, I would like to add as many as I want. 3. I don't know the coordinates of the polygon's vertex in advance, I want to get them by clicking on the map.

What I did so far: First, I wrote the OnMapClick method, which let me get the coordinates of the point I click and put them in an ArrayList (arrayPoints). Then the other two methods (onPolylineClick and onMarkerClick) allow me to "close" the polygon and thus to create it:

 @Override
    public void onMapClick(LatLng latLng) {

        MarkerOptions marker = new MarkerOptions();
        marker.position(latLng);
        mGoogleMap.addMarker(marker);

        polylineOptions = new PolylineOptions();
        polylineOptions.clickable(true);
        polylineOptions.color(Color.BLACK);
        polylineOptions.width(8);
        arrayPoints.add(latLng);

        polylineOptions.addAll(arrayPoints);


        mGoogleMap.addPolyline(polylineOptions);


    }


   @Override
    public void onPolylineClick(Polyline polyline) {

        Polygon polygon = mGoogleMap.addPolygon(new PolygonOptions()
                .clickable(true)
                .addAll(arrayPoints));


        stylePolygon(polygon);

    }


    @Override
    public boolean onMarkerClick(Marker marker) {

        if (arrayPoints.contains(marker.getPosition())) {
            polygon = mGoogleMap.addPolygon(new PolygonOptions()
                    .clickable(true)
                    .addAll(arrayPoints));


            stylePolygon(polygon);
            polygoncoord = polygon.getPoints().toString();
            Log.i("polygoncoord", polygon.getPoints().toString());
        } else {
            AddPointOfAnalysisLabel(label, point_coords);
        }
        return true;
    }

Now the problem is that if I keep clicking on the map after the first polygon is closed, I also keep adding new marker of the same polyline, instead of creating a new polygon.

My idea is that maybe I can click on the polygon to close it and then this will allows me to create a new one (without removing the first one). Therefore I already prepared the onPolygonClick method, but I really have know idea what to write in it to realize what I have in my mind... Can you please help me?

Thanks in advance!

Answer 1

关闭多边形后，您需要重置arrayPoints列表，以便可以开始为下一个多边形收集点。

arrayPoints.clear();