Question

我当时正在Android Studio（使用Java）中开发一个项目，并使用本教程将Google Maps嵌入到我的应用程序中： https://www.youtube.com/watch?v=CCZPUeY94MU

通过本教程，我可以输入位置和目的地并找到两者之间的路线。出于我的项目目的，我想要一个组成路径的坐标列表。汽车将通过的“每个”点。

我对编码还很陌生-如果缺少信息，请随时问我另一个问题。

谢谢。

Answer 1

public class DirectionFinder {

    private static final String DIRECTION_URL_API = "https://maps.googleapis.com/maps/api/directions/json?";
    private static final String GOOGLE_API_KEY = "your-api-key";
    private final DirectionFinderListener listener;
    private final String origin;
    private final String destination;

    public DirectionFinder(DirectionFinderListener listener, String origin, String destination) {
        this.listener = listener;
        this.origin = origin;
        this.destination = destination;
    }

    public void execute() throws UnsupportedEncodingException {
        listener.onDirectionFinderStart();
        new DownloadRawDataTask().execute(createUrl());
    }

    private String createUrl() throws UnsupportedEncodingException {
        String urlOrigin = URLEncoder.encode(origin, "utf-8");
        String urlDestination = URLEncoder.encode(destination, "utf-8");

        return DIRECTION_URL_API + "origin=" + urlOrigin + "&destination=" + urlDestination + "&key=" + GOOGLE_API_KEY;
    }

    private class DownloadRawDataTask extends AsyncTask<String, Void, String> {
        @Override
        protected String doInBackground(String... params) {
            String link = params[0];
            try {
                URL url = new URL(link);
                InputStream hInputStream = url.openConnection().getInputStream();
                StringBuffer hStringBuffer = new StringBuffer();
                BufferedReader hBufferedReader = new BufferedReader(new InputStreamReader(hInputStream));

                String line;
                while ((line = hBufferedReader.readLine()) != null) {
                    hStringBuffer.append(line + "\n");
                }

                return hStringBuffer.toString();

            } catch (IOException e) {
                e.printStackTrace();
            }
            return null;
        }

        @Override
        protected void onPostExecute(String res) {
            try {
                parseJSon(res);
            } catch (JSONException e) {
                e.printStackTrace();
            }
        }
    }

    private void parseJSon(String data) throws JSONException {
        if (data == null)
            return;
        try {
            List<Route> routes = new ArrayList<>();
            JSONObject jsonData = new JSONObject(data);
            JSONArray jsonRoutes = jsonData.getJSONArray("routes");
            for (int i = 0; i < jsonRoutes.length(); i++) {
                JSONObject jsonRoute = jsonRoutes.getJSONObject(i);
                Route route = new Route();

                JSONObject overview_polylineJson = jsonRoute.getJSONObject("overview_polyline");
                JSONArray jsonLegs = jsonRoute.getJSONArray("legs");
                JSONObject jsonLeg = jsonLegs.getJSONObject(0);
                JSONObject jsonDistance = jsonLeg.getJSONObject("distance");
                JSONObject jsonDuration = jsonLeg.getJSONObject("duration");
                JSONObject jsonEndLocation = jsonLeg.getJSONObject("end_location");
                JSONObject jsonStartLocation = jsonLeg.getJSONObject("start_location");

                // route.distance = new Distance(jsonDistance.getString("text"), jsonDistance.getInt("value"));
                //route.duration = new Duration(jsonDuration.getString("text"), jsonDuration.getInt("value"));
                route.endAddress = jsonLeg.getString("end_address");
                route.startAddress = jsonLeg.getString("start_address");
                route.startLocation = new LatLng(jsonStartLocation.getDouble("lat"), jsonStartLocation.getDouble("lng"));
                route.endLocation = new LatLng(jsonEndLocation.getDouble("lat"), jsonEndLocation.getDouble("lng"));
                route.points = decodePolyLine(overview_polylineJson.getString("points"));

                routes.add(route);
            }

            listener.onDirectionFinderSuccess(routes);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

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

。使用此类来查找方向和路线上的所有点。您进行活动的方式字符串原点= String.valueOf（route_Latitude）.concat（“，”）。concat（String.valueOf（route_Longitude））; 字符串目标= String.valueOf（routedestination_Lattitude）.concat（“，”）。concat（String.valueOf（routedestination_Longitude））; 新的DirectionFinder（this，起点，目的地）.execute（）;

返回组成Google Maps路径的坐标。

1 个答案: