android : get turn by turn direction of route between two geo locations

Question

I want to show turn by turn directions between two locations. I tried

 uri = "http://maps.google.com/maps?saddr="
                + "lat1" + ","
                +  "lon1" + "&daddr="
                + "lat2" + "," + "long2";
        Intent intent = new Intent(android.content.Intent.ACTION_VIEW,
                Uri.parse(uri));

It gives the route. But i dont want to open a browser and show. Instead is there a way to get the route so that it can be displayed in my own layout. For ex in text views.

You can send http request using googlemap api and parser response. — Trung Nguyen, Oct 18 '12 at 13:11
[The Google Directions API](https://developers.google.com/maps/documentation/directions/) — Trung Nguyen, Oct 18 '12 at 13:17
You want to get a line between your location and destination or the road name in the way between your location and destination ? — Trung Nguyen, Oct 18 '12 at 14:32
I want directions like 1. turn right and go 100m 2. turn left and go straight 500m ... Thank you. — png, Oct 24 '12 at 10:44
http://stackoverflow.com/questions/14702621/answer-draw-path-between-two-points-using-google-maps-android-api-v2 — Azahar, Dec 24 '13 at 12:36

score 2 · Answer 1 · answered Nov 01 '12 at 06:56

These code i wrote in my graduation project so they're not optimized.

MapService class: I parser data response from google map.

public class MapService {
public static final String TAG = "[MapService]";
public static final String GET_DIRECTION_URL = "http://maps.google.com/maps/api/directions/json?" + "origin=%f,%f" + "&destination=%f,%f" + "&sensor=true&language=en&units=metric";

public static DirectionResult getDirectionResult(double latitude1, double longtitude1, double latitude2, double longtitude2) {
    String url = String.format(GET_DIRECTION_URL, latitude1, longtitude1, latitude2, longtitude2);
    Log.d("URL", url);
    // parse direction
    DirectionParser directionParser = new DirectionParser() {
        @Override
        public void onSuccess(JSONObject json) throws JSONException {
            // process response status
            String status = json.getString("status");
            if (!status.equals("OK")) {
                String error = null;

                if (status.equals("NOT_FOUND") || status.equals("ZERO_RESULTS")) {
                    error = Global.application.getString(R.string.errCantGetDirection);
                } else {
                    error = Global.application.getString(R.string.errGetDirection);
                }

                result.instructions = new String[] { error };
                result.hasError = true;
                return;
            }

            /*
             * routes[] legs[] steps[] html_instructions
             */
            JSONArray arrRoutes = json.getJSONArray("routes");

            // no routes found
            if (arrRoutes.length() == 0) {
                result.instructions = new String[] { Global.application.getString(R.string.errCantGetDirection) };
                result.hasError = true;
                return;
            }

            JSONArray arrLegs = arrRoutes.getJSONObject(0).getJSONArray("legs");
            JSONObject firstLeg = arrLegs.getJSONObject(0);
            JSONArray arrSteps = firstLeg.getJSONArray("steps");
            int len = arrSteps.length();
            result.instructions = new String[len];
            result.points = new LinkedList<GeoPoint>();
            JSONObject leg = null;

            // get instructions
            for (int i = 0; i < len; ++i) {
                leg = arrSteps.getJSONObject(i);
                // location = leg.getJSONObject("start_location");
                String encoded = leg.getJSONObject("polyline").getString("points");
                result.points.addAll(decodePoly(encoded));

                result.instructions[i] = Html.fromHtml(leg.getString("html_instructions")).toString();
                Log.d("html_instructions", "" + Html.fromHtml(leg.getString("html_instructions")));
                // result.points[i] = new GeoPoint(
                // (int) (location.getDouble("lat") * 1E6),
                // (int) (location.getDouble("lng") * 1E6));
            }

            // location = leg.getJSONObject("end_location");
            // result.points[len] = new GeoPoint(
            // (int) (location.getDouble("lat") * 1E6),
            // (int) (location.getDouble("lng") * 1E6));

            // distance and duration info
            JSONObject distance = firstLeg.getJSONObject("distance");
            if (distance != null) {
                result.distance = distance.getString("text");
            }
            JSONObject duration = firstLeg.getJSONObject("duration");
            if (duration != null) {
                result.duration = duration.getString("text");
            }
        }

        @Override
        public void onFailure(String message) {
            String error = "Error";

            result.instructions = new String[] { error };
            result.hasError = true;
        }
    };

    // return direction result
    RestClient.getData(url, directionParser);
    return directionParser.result;
}

private static List<GeoPoint> decodePoly(String encoded) {
    List<GeoPoint> poly = new ArrayList<GeoPoint>();
    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;

        GeoPoint p = new GeoPoint((int) (((double) lat / 1E5) * 1E6), (int) (((double) lng / 1E5) * 1E6));
        poly.add(p);
    }

    return poly;
}

    }

Direction parser and direction result

public class DirectionParser extends JSONParser {
public DirectionResult result = new DirectionResult();

protected int jsonType = JSONParser.GOOGLE_DIRECTION_JSON;

public DirectionParser() {
    jsonType = JSONParser.GOOGLE_DIRECTION_JSON;
}

@Override
public void onFailure(String message) {
}

@Override
public void onSuccess(JSONObject json) throws JSONException {
}
}

public class DirectionResult {
 public String[] instructions;
 public List<GeoPoint> points;
 public String duration;
 public String distance;
 public boolean hasError = false;
}

What you want is the instruction of DirectionResult. You can simple create an array adapter with string array

 instructions = directionResult.instructions;// DirectionResult you got from MapService.
    ArrayAdapter<String> adapter1 = new ArrayAdapter<String>(DirectionListActivity.this, android.R.layout.simple_list_item_1, instructions);
                 listDirection.setAdapter(adapter1);

Update: Another parser i found Google-Maps-Directions-API-Java-Parser

score 0 · Answer 2 · answered Oct 18 '12 at 13:11

0

Check out GreatMaps. They have logic for retrieving routes. Its C# based, just use their logic and write the equivalent in Java.

http://greatmaps.codeplex.com/

answered Oct 18 '12 at 13:11

William Morrison

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android : get turn by turn direction of route between two geo locations

2 Answers2