display multiple routes in google map V2

Question

I am using this class to display a route on a map. The problem is that it only displays one route. What I want to do is display multiple alternate routes on the map. Even thought the server response has multiple routes, it only parses the first route and displays it. What changes should I make to display all the routes that the google server returns.Here is my class.

package com.maps.bestway;

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 org.json.JSONObject;

import android.annotation.SuppressLint;
import android.app.Activity;
import android.graphics.Color;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.widget.TextView;
import android.widget.Toast;

import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.GoogleMap.OnMapClickListener;
import com.google.android.gms.maps.MapFragment;
import com.google.android.gms.maps.model.BitmapDescriptorFactory;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;
import com.google.android.gms.maps.model.PolylineOptions;

public class map extends Activity {
GoogleMap map;
 ArrayList<LatLng> markerPoints;
TextView tvDistanceDuration;
 @SuppressLint("NewApi")
 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);

  tvDistanceDuration = (TextView) findViewById(R.id.tv_distance_time);

  // Initialising
  markerPoints = new ArrayList<LatLng>();


  map = ((MapFragment) getFragmentManager().findFragmentById(R.id.map))
    .getMap();
  // map.setMapType(GoogleMap.MAP_TYPE_HYBRID);
  // map.setMapType(GoogleMap.MAP_TYPE_NONE);
  map.setMapType(GoogleMap.MAP_TYPE_NORMAL);
  // map.setMapType(GoogleMap.MAP_TYPE_SATELLITE);
  // map.setMapType(GoogleMap.MAP_TYPE_TERRAIN);

//Enable MyLocation Button in the Map
  map.setMyLocationEnabled(true);

  //Checks whether the map is drawing traffic data
  //map.isTrafficEnabled();

  // Setting onclick event listener for the map
  map.setOnMapClickListener(new OnMapClickListener() {

      public void onMapClick(LatLng point) {

          // Already two locations
          if(markerPoints.size()>1){
              markerPoints.clear();
              map.clear();
          }

         // Adding new item to the ArrayList
          markerPoints.add(point);

          // Creating MarkerOptions
          MarkerOptions options = new MarkerOptions();

          // Setting the position of the marker
          options.position(point);

          /**
          * For the start location, the color of marker is GREEN and
          * for the end location, the color of marker is RED.
          */
          if(markerPoints.size()==1){
                      options.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_GREEN));
          }else if(markerPoints.size()==2){
                  options.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_RED));
          }

          // Add new marker to the Google Map Android API V2
          map.addMarker(options);

          // Checks, whether start and end locations are captured
          if(markerPoints.size() >= 2){
              LatLng origin = markerPoints.get(0);
              LatLng dest = markerPoints.get(1);

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

              DownloadTask downloadTask = new DownloadTask();

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

private String getDirectionsUrl(LatLng origin,LatLng dest){

  // Origin of route
  String str_origin = "origin="+origin.latitude+","+origin.longitude;

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

  // Sensor enabled
  String sensor = "sensor=false";

  //unit type 
  String unit = "units=metric";

  //add multipathes

  String pathes = "alternatives=true";

  // Building the parameters to the web service
  String parameters = str_origin+"&"+str_dest+"&"+sensor+"&"+unit+"&"+pathes;

  // Output format
  String output = "json";


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

  return url;
}

/** A 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);

      // Creating an http connection to communicate with url
      urlConnection = (HttpURLConnection) url.openConnection();

      // Connecting to url
      urlConnection.connect();

      // Reading data from url
      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 while downloading url", e.toString());
  }finally{
       iStream.close();
      urlConnection.disconnect();
   }
  return data;
}

// Fetches data from url passed
 private class DownloadTask extends AsyncTask<String, Void, String>{

  // Downloading data in non-ui thread
  @Override
  protected String doInBackground(String... url) {

       // For storing data from web service
       String data = "";

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

  // Executes in UI thread, after the execution of
  // doInBackground()
  @Override
  protected void onPostExecute(String result) {
      super.onPostExecute(result);

      ParserTask parserTask = new ParserTask();

      // Invokes the thread for parsing the JSON data
      parserTask.execute(result);
  }
}

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

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

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

      try{
          jObject = new JSONObject(jsonData[0]);
          DirectionsJSONParser parser = new DirectionsJSONParser();

          // Starts parsing data
          routes = parser.parse(jObject);
      }catch(Exception e){
          e.printStackTrace();
      }
      return routes;
  }

  // Executes in UI thread, after the parsing process
  protected void onPostExecute(List<List<HashMap<String, String>>> result) {
      ArrayList<LatLng> points = null;
      PolylineOptions lineOptions = null;
      MarkerOptions markerOptions = new MarkerOptions();
      String distance = "";
      String duration = "";

      if(result.size()<1){
          Toast.makeText(getBaseContext(), "No Points", Toast.LENGTH_SHORT).show();
          return;
      }

      // Traversing through all the routes
      for(int i=0;i<result.size();i++){
          points = new ArrayList<LatLng>();
          lineOptions = new PolylineOptions();

          // Fetching i-th route
          List<HashMap<String, String>> path = result.get(i);

          // Fetching all the points in i-th route
          for(int j=0;j<path.size();j++){
              HashMap<String,String> point = path.get(j);

             if(j==0){    // Get distance from the list
                  distance = (String)point.get("distance");
                  continue;
              }else if(j==1){ // Get duration from the list
                  duration = (String)point.get("duration");
                  continue;
              }

              double lat = Double.parseDouble(point.get("lat"));
              double lng = Double.parseDouble(point.get("lng"));
              LatLng position = new LatLng(lat, lng);

              points.add(position);
          }

          // Adding all the points in the route to LineOptions
          lineOptions.addAll(points);
          lineOptions.width(4);
          lineOptions.color(Color.CYAN);
      }

      tvDistanceDuration.setText("Distance:"+distance + ", Duration:"+duration);

      // Drawing polyline in the Google Map for the i-th route
      map.addPolyline(lineOptions);
  }
}

}

Answer 1

i went throw this code and the problem was i misplaced on of the for brackets in onPostExecute function and this is the right code for it:

protected void onPostExecute(List<List<HashMap<String, String>>> result) {
  ArrayList<LatLng> points = null;
  PolylineOptions lineOptions = null;
  MarkerOptions markerOptions = new MarkerOptions();
  String distance = "";
  String duration = "";

  if(result.size()<1){
      Toast.makeText(getBaseContext(), "No Points", Toast.LENGTH_SHORT).show();
      return;
  }

  // Traversing through all the routes
  for(int i=0;i<result.size();i++){
      points = new ArrayList<LatLng>();
      lineOptions = new PolylineOptions();

      // Fetching i-th route
      List<HashMap<String, String>> path = result.get(i);

      // Fetching all the points in i-th route
      for(int j=0;j<path.size();j++){
          HashMap<String,String> point = path.get(j);

         if(j==0){    // Get distance from the list
              distance = (String)point.get("distance");
              continue;
          }else if(j==1){ // Get duration from the list
              duration = (String)point.get("duration");
              continue;
          }

          double lat = Double.parseDouble(point.get("lat"));
          double lng = Double.parseDouble(point.get("lng"));
          LatLng position = new LatLng(lat, lng);

          points.add(position);
      }

      // Adding all the points in the route to LineOptions
      lineOptions.addAll(points);
      lineOptions.width(4);
      lineOptions.color(Color.CYAN);


  tvDistanceDuration.setText("Distance:"+distance + ", Duration:"+duration);

  // Drawing polyline in the Google Map for the i-th route
  map.addPolyline(lineOptions);
    }
  }
}