How to draw route directions from a marker to another one ? Googlemaps v2 Android

Question

Here is my code :

    public class MyGoogleMapActivity extends FragmentActivity {


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

            GoogleMap map = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map)).getMap();

            map.setMyLocationEnabled(true);

            LatLng Paris= new LatLng(64.711696, 12.170481);
            map.addMarker(new MarkerOptions().title("LolluSaba").position(Paris));
            LatLng Cinema= new LatLng(34.711696, 2.170481);
            map.addMarker(new MarkerOptions().title("Pseudo").position(Cinema));
       }
    }

And i like to draw a route from Paris to Cinema. How can I do it very simply ?

Answer 1

As you have two points so send it through google json which provides to draw route between two points. See this example.

Route direction between two location

Answer 2

Assuming that you have the coordinates of the two points you want to draw, you can get the route from google using the following methods:

class GetDirection extends AsyncTask<String, String, String> {

    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        dialog = new ProgressDialog(MapaAnunciante.this);
        dialog.setMessage("Drawing the route, please wait!");
        dialog.setIndeterminate(false);
        dialog.setCancelable(false);
        dialog.show();
    }

    protected String doInBackground(String... args) {
        String stringUrl = "http://maps.googleapis.com/maps/api/directions/json?origin=" + origin+ "&destination=" + destination+ "&sensor=false";
        StringBuilder response = new StringBuilder();
        try {
            URL url = new URL(stringUrl);
            HttpURLConnection httpconn = (HttpURLConnection) url
                    .openConnection();
            if (httpconn.getResponseCode() == HttpURLConnection.HTTP_OK) {
                BufferedReader input = new BufferedReader(
                        new InputStreamReader(httpconn.getInputStream()),
                        8192);
                String strLine = null;

                while ((strLine = input.readLine()) != null) {
                    response.append(strLine);
                }
                input.close();
            }

            String jsonOutput = response.toString();

            JSONObject jsonObject = new JSONObject(jsonOutput);

            // routesArray contains ALL routes
            JSONArray routesArray = jsonObject.getJSONArray("routes");
            // Grab the first route
            JSONObject route = routesArray.getJSONObject(0);

            JSONObject poly = route.getJSONObject("overview_polyline");
            String polyline = poly.getString("points");
            pontos = decodePoly(polyline);

        } catch (Exception e) {

        }

        return null;

    }

    protected void onPostExecute(String file_url) {
        for (int i = 0; i < pontos.size() - 1; i++) {
            LatLng src = pontos.get(i);
            LatLng dest = pontos.get(i + 1);
            try{
                //here is where it will draw the polyline in your map
                Polyline line = map.addPolyline(new PolylineOptions()
                    .add(new LatLng(src.latitude, src.longitude),
                            new LatLng(dest.latitude,                dest.longitude))
                    .width(2).color(Color.RED).geodesic(true));
            }catch(NullPointerException e){
                Log.e("Error", "NullPointerException onPostExecute: " + e.toString());
            }catch (Exception e2) {
                Log.e("Error", "Exception onPostExecute: " + e2.toString());
            }

        }
        dialog.dismiss();

    }
}

private List<LatLng> decodePoly(String encoded) {

    List<LatLng> poly = new ArrayList<LatLng>();
    int index = 0, len = encoded.length();
    int lat = 0, lng = 0;

    while (index < len) {
        int b, shift = 0, result = 0;
        do {
            b = encoded.charAt(index++) - 63;
            result |= (b & 0x1f) << shift;
            shift += 5;
        } while (b >= 0x20);
        int dlat = ((result & 1) != 0 ? ~(result >> 1) : (result >> 1));
        lat += dlat;

        shift = 0;
        result = 0;
        do {
            b = encoded.charAt(index++) - 63;
            result |= (b & 0x1f) << shift;
            shift += 5;
        } while (b >= 0x20);
        int dlng = ((result & 1) != 0 ? ~(result >> 1) : (result >> 1));
        lng += dlng;

        LatLng p = new LatLng((((double) lat / 1E5)),
                (((double) lng / 1E5)));
        poly.add(p);
    }

    return poly;
}

Where origin and destination are two strings containing the lat and lng of the points, formatted like "-1.0,2.0":

 String origin = "64.711696,12.170481";
 String destination = "34.711696,2.170481";

To execute it, just call new GetDirection().execute();

Hope it helps!

Answer 3

You Need to use the Directions API in combination with the Android Maps util Lib

1. Get the Encoded Polyline String from the Directions Api.
2. Decode the encoded string using Maps Util Lib into a list of lat/lng's (https://developers.google.com/maps/documentation/android/utility/#poly-encoding)
3. Draw the Polyline on the map using the lat/lngs!

Answer 4

First a List of LatLng you need

List<LatLng> ls_pos=new ArrayList<>();

After that In OnMapReady

mMap.setOnMarkerClickListener(new GoogleMap.OnMarkerClickListener() {
            @Override
            public boolean onMarkerClick(final Marker marker) {
   if (ls_pos.size() >= 2) {

 mMap.addPolyline(newPolylineOptions().addAll(ls_pos).width(10).color(Color.RED).visible(true).clickable(true));

     ls_pos.clear

That's Work for me.