Почему не рисуется polyline между точками?

Question

[DmitrijP]

Добрый день!
Использую google maps api для создания своего приложения. Код должен прокладывать маршрут на карте используя Polyline. Однако, точки отмечаются, линяя не получается, в чём может быть проблема? (код в спойлере)

Код

import android.graphics.Color;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.OnMapReadyCallback;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;
import com.google.android.gms.maps.model.PolylineOptions;
import org.json.JSONObject;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;

import androidx.fragment.app.FragmentActivity;

public class MapsActivity extends FragmentActivity implements OnMapReadyCallback {

    private GoogleMap mMap;

    MarkerOptions origin, destination;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_maps);

        // Obtain the SupportMapFragment and get notified when the map is ready to be used.
        SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
                .findFragmentById(R.id.map);
        mapFragment.getMapAsync(this);

        //Setting marker to draw route between these two points
        /**
         * later to use tracking for app combine gps_tracker part for getting coordinates every time but save origin point by making condition in a loop/saving points
         * **/
        origin = new MarkerOptions().position(new LatLng(51.58, 10.667)).title("Origin layout").snippet("origin");
        destination = new MarkerOptions().position(new LatLng(51.2904, 10.666)).title("Destination").snippet("destination");

        // Getting URL to the Google Directions API
        String url = getDirectionsUrl(origin.getPosition(), destination.getPosition());

        DownloadTask downloadTask = new DownloadTask();

        // Start downloading json data from Google Directions API
        downloadTask.execute(url);

    }

    @Override

    public void onMapReady(GoogleMap googleMap){
        mMap = googleMap;
        mMap.addMarker(origin);
        mMap.addMarker(destination);
        mMap.animateCamera(CameraUpdateFactory.newLatLngZoom(origin.getPosition(), 9));
    }
    private class DownloadTask extends AsyncTask<String, Void, String> {

        @Override
        protected String doInBackground(String... url) {

            String data = "";

            try {
                data = downloadUrl(url[0]);
            } catch (Exception e) {
                Log.d("Background Task", e.toString());
            }
            return data;
        }

        @Override
        protected void onPostExecute(String result) {
            super.onPostExecute(result);
            ParserTask parserTask = new ParserTask();
            parserTask.execute(result);
        }
    }

    /**
     * Class to parse the JSON format
     */
    private class ParserTask extends AsyncTask<String, Integer, List<List<HashMap<String, String>>>> {

        // Parsing the data in non-ui thread
        @Override
        protected List<List<HashMap<String, String>>> doInBackground(String... jsonData){

            JSONObject jObject;
            List<List<HashMap<String, String>>> routes = null;

            try {
                jObject = new JSONObject(jsonData[0]);
                DataParser parser = new DataParser();
                routes = parser.parse(jObject);
            } catch (Exception e){
                e.printStackTrace();
            }
            return routes;
        }


        @Override
        protected void onPostExecute(List<List<HashMap<String, String>>> result) {
            ArrayList points = new ArrayList();


            for (int i = 0; i < result.size(); i++) {

                List<HashMap<String, String>> path = result.get(i);

                for (int j = 0; j < path.size(); j++) {
                    HashMap<String, String> point = path.get(j);
                    double lat = Double.parseDouble(point.get("lat"));
                    double lng = Double.parseDouble(point.get("lng"));
                    LatLng position = new LatLng(lat, lng);

                    points.add(position);
                }



            }

            // Drawing polyline in the Google Map
            mMap.getUiSettings().setZoomControlsEnabled(true);

            if (points.size() > 0) {
                PolylineOptions opts = new PolylineOptions().add(origin.getPosition(), destination.getPosition()).color(Color.BLUE).width(5);
                mMap.addPolyline(opts);
            }

        }
    }



    private String getDirectionsUrl(LatLng origin, LatLng dest){
        //origin fo route
        String str_origin  = "origin=" + origin.latitude + "," + origin.longitude;

        //destination of route
        String str_dest = "destination=" + dest.latitude + "," + dest.longitude;

        //Setting mode
        String mode = "mode=driving";

        //Building the parameters to the web service
        String parametrs = str_origin + "&" + str_dest + "&" + mode;

        //Output format
        String output = "json";

        //Building the url to the web service
        String url = "https://maps.googleapis.com/maps/api/directions/" + output + "?" +parametrs + "&key=" + "AIzaSyD_L8g3AcwXBKnEjhvLJwBXwI3L51LjQUU";

        return url;

    }

    /**
     *  method to download json data from url
     */


    private String downloadUrl(String strUrl) throws IOException{
        String data = "";
        InputStream iStream = null;
        HttpURLConnection urlConnection = null;
        try {
            URL url = new URL(strUrl);
            urlConnection = (HttpURLConnection) url.openConnection();

            urlConnection.connect();

            iStream = urlConnection.getInputStream();
            BufferedReader br = new BufferedReader(new InputStreamReader(iStream));
            StringBuffer sb = new StringBuffer();
            String line = "";
            while ((line = br.readLine()) != null) {
                sb.append(line);
            }
            data = sb.toString();
            br.close();
        } catch (Exception e){
            Log.d("Exception", e.toString());
        } finally{
            iStream.close();
            urlConnection.disconnect();
        }
        return data;
    }

}