Android Open Source - Google-Directions-Android Google Parser

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License

The source code is released under:

Copyright (c) 2013 Joel Dean Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software...

Java Source Code

package com.directions.route;
/*w  w w .j  a  v  a  2  s. c om*/
import android.util.Log;

import com.google.android.gms.maps.model.LatLng;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;

public class GoogleParser extends XMLParser implements Parser {
    /**
     * Distance covered. *
     */
    private int distance;

    public GoogleParser(String feedUrl) {
        super(feedUrl);
    }

    /**
     * Parses a url pointing to a Google JSON object to a Route object.
     *
     * @return a Route object based on the JSON object by Haseem Saheed
     */

    public Route parse() {
        // turn the stream into a string
        final String result = convertStreamToString(this.getInputStream());
        if (result == null) return null;

        //Create an empty route
        final Route route = new Route();
        //Create an empty segment
        final Segment segment = new Segment();
        try {
            //Tranform the string into a json object
            final JSONObject json = new JSONObject(result);
            //Get the route object
            final JSONObject jsonRoute = json.getJSONArray("routes").getJSONObject(0);
            //Get the leg, only one leg as we don't support waypoints
            final JSONObject leg = jsonRoute.getJSONArray("legs").getJSONObject(0);
            //Get the steps for this leg
            final JSONArray steps = leg.getJSONArray("steps");
            //Number of steps for use in for loop
            final int numSteps = steps.length();
            //Set the name of this route using the start & end addresses
            route.setName(leg.getString("start_address") + " to " + leg.getString("end_address"));
            //Get google's copyright notice (tos requirement)
            route.setCopyright(jsonRoute.getString("copyrights"));
            //Get distance and time estimation
            route.setDurationText(leg.getJSONObject("duration").getString("text"));
            route.setDistanceText(leg.getJSONObject("distance").getString("text"));
            route.setEndAddressText(leg.getString("end_address"));
            //Get the total length of the route.
            route.setLength(leg.getJSONObject("distance").getInt("value"));
            //Get any warnings provided (tos requirement)
            if (!jsonRoute.getJSONArray("warnings").isNull(0)) {
                route.setWarning(jsonRoute.getJSONArray("warnings").getString(0));
            }
                    /* Loop through the steps, creating a segment for each one and
                     * decoding any polylines found as we go to add to the route object's
                     * map array. Using an explicit for loop because it is faster!
                     */
            for (int i = 0; i < numSteps; i++) {
                //Get the individual step
                final JSONObject step = steps.getJSONObject(i);
                //Get the start position for this step and set it on the segment
                final JSONObject start = step.getJSONObject("start_location");
                final LatLng position = new LatLng(start.getDouble("lat"),
                        start.getDouble("lng"));
                segment.setPoint(position);
                //Set the length of this segment in metres
                final int length = step.getJSONObject("distance").getInt("value");
                distance += length;
                segment.setLength(length);
                segment.setDistance(distance / 1000);
                //Strip html from google directions and set as turn instruction
                segment.setInstruction(step.getString("html_instructions").replaceAll("<(.*?)*>", ""));
                //Retrieve & decode this segment's polyline and add it to the route.
                route.addPoints(decodePolyLine(step.getJSONObject("polyline").getString("points")));
                //Push a copy of the segment to the route
                route.addSegment(segment.copy());
            }
        } catch (JSONException e) {
            Log.e("Routing Error", e.getMessage());
            return null;
        }
        return route;
    }

    /**
     * Convert an inputstream to a string.
     *
     * @param input inputstream to convert.
     * @return a String of the inputstream.
     */

    private static String convertStreamToString(final InputStream input) {
        if (input == null) return null;

        final BufferedReader reader = new BufferedReader(new InputStreamReader(input));
        final StringBuilder sBuf = new StringBuilder();

        String line = null;
        try {
            while ((line = reader.readLine()) != null) {
                sBuf.append(line);
            }
        } catch (IOException e) {
            Log.e("Routing Error", e.getMessage());
        } finally {
            try {
                input.close();
            } catch (IOException e) {
                Log.e("Routing Error", e.getMessage());
            }
        }
        return sBuf.toString();
    }

    /**
     * Decode a polyline string into a list of GeoPoints.
     *
     * @param poly polyline encoded string to decode.
     * @return the list of GeoPoints represented by this polystring.
     */

    private List<LatLng> decodePolyLine(final String poly) {
        int len = poly.length();
        int index = 0;
        List<LatLng> decoded = new ArrayList<LatLng>();
        int lat = 0;
        int lng = 0;

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

            decoded.add(new LatLng(
                    lat / 100000d, lng / 100000d
            ));
        }

        return decoded;
    }
}

Java Source Code List

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