I want to show alternative multiple routes in google map. In my code I have set my location as source and a static place as destination. I have successfully drawn single route using this .
Can anyone please tell me , how can I show alternative routes for the same destination ?
Thanks.
I think you can do something like this
LatLng origin = sourcePosition;
LatLng dest = destPosition;
DownloadTask1 downloadTask = new DownloadTask1();
String url = downloadTask.getDirectionsUrl1(origin, dest);
downloadTask.execute(url);
DownloadTask1 class
private class DownloadTask1 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);
ParserTask1 parserTask = new ParserTask1();
// Invokes the thread for parsing the JSON data
parserTask.execute(result);
}
private String getDirectionsUrl1(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&alternatives=true&units=metric&mode=driving";
//&alternatives=true&units=metric&mode=driving
// Building the parameters to the web service
String parameters = str_origin + "&" + str_dest + "&" + sensor;
// 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;
}
}
downloadUrl() method
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){
e.printStackTrace();
//Log.d("Exception while downloading url", e.toString());
}finally{
iStream.close();
urlConnection.disconnect();
}
return data;
}
ParserTask1 class
private class ParserTask1 extends AsyncTask<String, Integer, List<List<List<HashMap<String, String>>>>> {
// Parsing the data in non-ui thread
@Override
protected List<List<List<HashMap<String, String>>>> doInBackground(String... jsonData) {
JSONObject jObject;
List<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
@Override
protected void onPostExecute(List<List<List<HashMap<String, String>>>> result) {
ArrayList<LatLng> points = null;
PolylineOptions lineOptions = new PolylineOptions();
PolylineOptions lineOptions1 = null;
MarkerOptions markerOptions = new MarkerOptions();
String distance = "";
String duration = "";
Integer size1 = 0;
Integer size2 = 0;
Integer size3 = 0;
// Log.d(SHETTY, "onPostExecute: result set "+result.size());
List<LatLng> aline1 = new ArrayList<LatLng>();
List<LatLng> aline2 = new ArrayList<LatLng>();
List<LatLng> aline3 = new ArrayList<LatLng>();
if (result != null) {
int i = 0;
Log.d(SHETTY, "onPostExecute: result size " + result.size());
while (i < result.size()) {
// for(int i=0;i<result.size();i++){
//result.size()
//int g= i-1;
points = new ArrayList<LatLng>();
// lineOptions = new PolylineOptions();
// if(i==1){
// }else{
List<List<HashMap<String, String>>> path1 = result.get(i);
for (int s = 0; s < path1.size(); s++) {
Log.d("pathsize1", path1.size() + "");
// Fetching i-th route
List<HashMap<String, String>> path = path1.get(s);
Log.d("pathsize", path.size() + "");
// Fetching all the points in i-th route
for (int j = 0; j < path.size(); j++) {
lineOptions1 = new PolylineOptions();
HashMap<String, String> point = path.get(j);
// points = new ArrayList<LatLng>();
// 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);
// Log.d("latlng", position.toString());
points.add(position);
}
// lineOptions.addAll(points);
// lineOptions.width(5);
// lineOptions.color(Color.BLUE);
// map.addPolyline(lineOptions);
}
// }
if (i == 0) {
// line1.addAll(points);
// mMap.addPolyline(line1);
size1 = points.size();
aline1.addAll(points);
} else if (i == 1) {
// line2.addAll(points);
// mMap.addPolyline(line2);
aline2.addAll(points);
size2 = points.size();
} else if (i == 2) {
// line3.addAll(points);
// mMap.addPolyline(line3);
aline3.addAll(points);
size3 = points.size();
}
// Adding all the points in the route to LineOptions
i++;
}
// Drawing polyline in the Google Map for the i-th route
// map.addPolyline(lineOptions);
}
if (size3 != 0)
{
if ((size1 > size2 && size1 > size3)) {
if (size2 > size3) {
PolylineOptions line1 = new PolylineOptions().width(8).color(getActivity().getResources().getColor(R.color.grey));
PolylineOptions line2 = new PolylineOptions().width(8).color(getActivity().getResources().getColor(R.color.grey));
PolylineOptions line3 = new PolylineOptions().width(8).color(getActivity().getResources().getColor(R.color.lightblue));
line1.addAll(aline1);
line2.addAll(aline2);
line3.addAll(aline3);
mMap.addPolyline(line1);
mMap.addPolyline(line2);
mMap.addPolyline(line3);
Log.d(SHETTY, "onPostExecute: 3110 ");
} else {
PolylineOptions line1 = new PolylineOptions().width(8).color(getActivity().getResources().getColor(R.color.grey));
PolylineOptions line2 = new PolylineOptions().width(8).color(getActivity().getResources().getColor(R.color.lightblue));
PolylineOptions line3 = new PolylineOptions().width(8).color(getActivity().getResources().getColor(R.color.grey));
line1.addAll(aline1);
line2.addAll(aline2);
line3.addAll(aline3);
mMap.addPolyline(line1);
mMap.addPolyline(line3);
mMap.addPolyline(line2);
Log.d(SHETTY, "onPostExecute: 3127 ");
}
} else if ((size2 > size1 && size2 > size3)) {
if (size1 > size3) {
PolylineOptions line1 = new PolylineOptions().width(8).color(getActivity().getResources().getColor(R.color.grey));
PolylineOptions line2 = new PolylineOptions().width(8).color(getActivity().getResources().getColor(R.color.grey));
PolylineOptions line3 = new PolylineOptions().width(8).color(getActivity().getResources().getColor(R.color.lightblue));
line1.addAll(aline1);
line2.addAll(aline2);
line3.addAll(aline3);
mMap.addPolyline(line1);
mMap.addPolyline(line2);
mMap.addPolyline(line3);
Log.d(SHETTY, "onPostExecute: 3147 ");
} else {
PolylineOptions line1 = new PolylineOptions().width(8).color(getActivity().getResources().getColor(R.color.lightblue));
PolylineOptions line2 = new PolylineOptions().width(8).color(getActivity().getResources().getColor(R.color.grey));
PolylineOptions line3 = new PolylineOptions().width(8).color(getActivity().getResources().getColor(R.color.grey));
line1.addAll(aline1);
line2.addAll(aline2);
line3.addAll(aline3);
mMap.addPolyline(line2);
mMap.addPolyline(line3);
mMap.addPolyline(line1);
Log.d(SHETTY, "onPostExecute: 3164 ");
}
} else if ((size3 > size1 && size3 > size2)) {
if (size1 > size2) {
PolylineOptions line1 = new PolylineOptions().width(8).color(getActivity().getResources().getColor(R.color.grey));
PolylineOptions line2 = new PolylineOptions().width(8).color(getActivity().getResources().getColor(R.color.lightblue));
PolylineOptions line3 = new PolylineOptions().width(8).color(getActivity().getResources().getColor(R.color.grey));
line1.addAll(aline1);
line2.addAll(aline2);
line3.addAll(aline3);
mMap.addPolyline(line3);
mMap.addPolyline(line1);
mMap.addPolyline(line2);
Log.d(SHETTY, "onPostExecute: 3182 ");
} else {
PolylineOptions line1 = new PolylineOptions().width(8).color(getActivity().getResources().getColor(R.color.lightblue));
PolylineOptions line2 = new PolylineOptions().width(8).color(getActivity().getResources().getColor(R.color.grey));
PolylineOptions line3 = new PolylineOptions().width(8).color(getActivity().getResources().getColor(R.color.grey));
line1.addAll(aline1);
line2.addAll(aline2);
line3.addAll(aline3);
mMap.addPolyline(line3);
mMap.addPolyline(line2);
mMap.addPolyline(line1);
Log.d(SHETTY, "onPostExecute: 3196 ");
}
} else {
System.out.println("ERROR!");
}
}else if(size2!=0)
{
if(size1>size2){
PolylineOptions line1 = new PolylineOptions().width(8).color(getActivity().getResources().getColor(R.color.grey));
PolylineOptions line2 = new PolylineOptions().width(8).color(getActivity().getResources().getColor(R.color.lightblue));
line1.addAll(aline1);
line2.addAll(aline2);
mMap.addPolyline(line1);
mMap.addPolyline(line2);
}else
{
PolylineOptions line1 = new PolylineOptions().width(8).color(getActivity().getResources().getColor(R.color.lightblue));
PolylineOptions line2 = new PolylineOptions().width(8).color(getActivity().getResources().getColor(R.color.grey));
line1.addAll(aline1);
line2.addAll(aline2);
mMap.addPolyline(line2);
mMap.addPolyline(line1);
}
}
else if(size1!=0){
PolylineOptions line1 = new PolylineOptions().width(8).color(getActivity().getResources().getColor(R.color.lightblue));
line1.addAll(aline1);
mMap.addPolyline(line1);
}
}
}
Now for parsing JObject create DirectionsJSONParser class
public class DirectionsJSONParser {
/**
* Receives a JSONObject and returns a list of lists containing latitude and
* longitude
*/
public List<List<List<HashMap<String,String>>>> parse(JSONObject jObject){
List<List<HashMap<String, String>>> routes = new ArrayList<List<HashMap<String,String>>>() ;
List<List<List<HashMap<String,String>>>> routes1 = new ArrayList<List<List<HashMap<String,String>>>>() ;
JSONArray jRoutes = null;
JSONArray jLegs = null;
JSONArray jSteps = null;
try {
jRoutes = jObject.getJSONArray("routes");
/** Traversing all routes */
for(int i=0;i<jRoutes.length();i++){
jLegs = ( (JSONObject)jRoutes.get(i)).getJSONArray("legs");
List path = new ArrayList<HashMap<String, String>>();
List path1 = new ArrayList<ArrayList<HashMap<String,String>>>();
// Log.d("legs",jLegs.toString());
/** Traversing all legs */
for(int j=0;j<jLegs.length();j++){
HashMap<String, String> hm1 = new HashMap<String, String>();
jSteps = ( (JSONObject)jLegs.get(j)).getJSONArray("steps");
// Log.d("steps",jSteps.toString());
/** Traversing all steps */
for(int k=0;k<jSteps.length();k++){
String polyline = "";
polyline = (String)((JSONObject)((JSONObject)jSteps.get(k)).get("polyline")).get("points");
List<LatLng> list = decodePoly(polyline);
// Log.d("polyline",polyline.toString());
/** Traversing all points */
for(int l=0;l<list.size();l++){
HashMap<String, String> hm = new HashMap<String, String>();
hm.put("lat", Double.toString(((LatLng)list.get(l)).latitude) );
hm.put("lng", Double.toString(((LatLng)list.get(l)).longitude) );
path.add(hm);
// Log.d("lat", Double.toString(((LatLng)list.get(l)).latitude));
// Log.d("lng", Double.toString(((LatLng)list.get(l)).longitude));
}
}
path1.add(path);
}
routes1.add(path1);
}
} catch (JSONException e) {
e.printStackTrace();
}catch (Exception e){
}
return routes1;
}
/**
* Method to decode polyline points
* Courtesy : http://jeffreysambells.com/2010/05/27/decoding-polylines-from-google-maps-direction-api-with-java
* */
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;
}
}
At the end you'll have main route in blue colour and alternatives in grey. Hope it helps.
Google Directions API have 4 different parameters for drawing routes. https://developers.google.com/maps/documentation/directions/#TravelModes
driving, walking, bicycling, transit
So you can use this parameters and try to get different routes.
Sometimes they can be equal to each other(for example walking and bicycling) between locations that near each other.
But you can handle this and just don't draw duplicates.
Also you can try to create your one mechanism for drawing routes between 2 points on map(maybe just straight line :)). But if you want something complicated it will be really difficult to create this yourself.
