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copied!<p>First of all we will get source and destination points between which we have to draw route. Then we will pass these attribute to below function.</p> <pre><code> public String makeURL (double sourcelat, double sourcelog, double destlat, double destlog ){ StringBuilder urlString = new StringBuilder(); urlString.append("http://maps.googleapis.com/maps/api/directions/json"); urlString.append("?origin=");// from urlString.append(Double.toString(sourcelat)); urlString.append(","); urlString .append(Double.toString( sourcelog)); urlString.append("&destination=");// to urlString .append(Double.toString( destlat)); urlString.append(","); urlString.append(Double.toString( destlog)); urlString.append("&sensor=false&mode=driving&alternatives=true"); urlString.append("&key=YOUR_API_KEY"); return urlString.toString(); } </code></pre> <p>This function will make the url that we will send to get Direction API response. Then we will parse that response . The parser class is</p> <pre><code>public class JSONParser { static InputStream is = null; static JSONObject jObj = null; static String json = ""; // constructor public JSONParser() { } public String getJSONFromUrl(String url) { // Making HTTP request try { // defaultHttpClient DefaultHttpClient httpClient = new DefaultHttpClient(); HttpPost httpPost = new HttpPost(url); HttpResponse httpResponse = httpClient.execute(httpPost); HttpEntity httpEntity = httpResponse.getEntity(); is = httpEntity.getContent(); } catch (UnsupportedEncodingException e) { e.printStackTrace(); } catch (ClientProtocolException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } try { BufferedReader reader = new BufferedReader(new InputStreamReader( is, "iso-8859-1"), 8); StringBuilder sb = new StringBuilder(); String line = null; while ((line = reader.readLine()) != null) { sb.append(line + "\n"); } json = sb.toString(); is.close(); } catch (Exception e) { Log.e("Buffer Error", "Error converting result " + e.toString()); } return json; } } </code></pre> <p>This parser will return us string. We will call it like that.</p> <pre><code>JSONParser jParser = new JSONParser(); String json = jParser.getJSONFromUrl(url); </code></pre> <p>Now we will send this string to our drawpath function. The drawpath function is </p> <pre><code>public void drawPath(String result) { try { //Tranform the string into a json object final JSONObject json = new JSONObject(result); JSONArray routeArray = json.getJSONArray("routes"); JSONObject routes = routeArray.getJSONObject(0); JSONObject overviewPolylines = routes.getJSONObject("overview_polyline"); String encodedString = overviewPolylines.getString("points"); List<LatLng> list = decodePoly(encodedString); Polyline line = mMap.addPolyline(new PolylineOptions() .addAll(list) .width(12) .color(Color.parseColor("#05b1fb"))//Google maps blue color .geodesic(true) ); /* for(int z = 0; z<list.size()-1;z++){ LatLng src= list.get(z); LatLng dest= list.get(z+1); Polyline line = mMap.addPolyline(new PolylineOptions() .add(new LatLng(src.latitude, src.longitude), new LatLng(dest.latitude, dest.longitude)) .width(2) .color(Color.BLUE).geodesic(true)); } */ } catch (JSONException e) { } } </code></pre> <p>Above code will draw the path on mMap. The code of decodePoly is</p> <pre><code>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; } </code></pre> <p>As direction call may take time so we will do all this in Asynchronous task. My Asynchronous task was </p> <pre><code>private class connectAsyncTask extends AsyncTask<Void, Void, String>{ private ProgressDialog progressDialog; String url; connectAsyncTask(String urlPass){ url = urlPass; } @Override protected void onPreExecute() { // TODO Auto-generated method stub super.onPreExecute(); progressDialog = new ProgressDialog(MainActivity.this); progressDialog.setMessage("Fetching route, Please wait..."); progressDialog.setIndeterminate(true); progressDialog.show(); } @Override protected String doInBackground(Void... params) { JSONParser jParser = new JSONParser(); String json = jParser.getJSONFromUrl(url); return json; } @Override protected void onPostExecute(String result) { super.onPostExecute(result); progressDialog.hide(); if(result!=null){ drawPath(result); } } } </code></pre> <p>I hope it will help.</p>

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