如何通过Google Map API通过公路获取距离

Question

我想在我的应用中通过步行和驾车来获取距离。我已经按行获取了距离，但是现在我想要确切的距离。我已阅读为Google帐户启用API密钥计费功能，并且已经完成了。现在我不明白他的代码，我已经看过多个并尝试过，但是不了解如何使用Google指南中提供的API。有时应用程序崩溃，有时它什么也没有响应。首先，我想做的是获得只有步行或乘车即可的确切距离。任何帮助将不胜感激我尝试过的最后一个代码，但是什么也没做]

origin = new LatLng(currentLat, currentLong);
                    dest = new LatLng(donarLat, donarLong);
                    String url = getDirectionsUrl();
                    DownloadTask downloadTask = new DownloadTask();
                    downloadTask.execute(url);

 private String getDirectionsUrl() {
        // Origin of route
        String str_origin = "origin=" + currentLat + "," + currentLong;
        // Destination of route
        String str_dest = "destination=" + donarLat + "," + donarLong;
        // Sensor enabled
        String sensor = "sensor=false";
        // Building the parameters to the web service
        String key = "key=" + "**********NR9TxLUwXyeq0jwV6k************";
        String parameters = str_origin + "&" + str_dest + "&" + sensor + "&" + key;
        // 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) {
            Toast.makeText(this, e.getMessage(), Toast.LENGTH_SHORT).show();
        } finally {
            iStream.close();
            urlConnection.disconnect();
        }
        return data;
    }

    // Fetches data from url passed
    private class DownloadTask extends AsyncTask<String, Void, ArrayList<String>> {
        @Override
        protected ArrayList<String> doInBackground(String... urlList) {
            try {
                ArrayList<String> returnList = new ArrayList<String>();
                for (String url : urlList) {
                }
                return returnList;
            } catch (Exception e) {
                Log.d("Background Task", e.toString());
                return null; // Failed, return null
            }
        }

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

            ParserTask parserTask = new ParserTask();

            for (String url : results) {
                parserTask.execute(url);
            }

        }
    }

    /**
     * A class to parse the Google Places in JSON format
     */
    private class ParserTask extends AsyncTask<String, Integer, ArrayList<List<HashMap<String, String>>>> {
        // Parsing the data in non-ui thread
        @Override
        protected ArrayList<List<HashMap<String, String>>> doInBackground(String... jsonData) {
            try {
                ArrayList<List<HashMap<String, String>>> routes = new ArrayList<List<HashMap<String, String>>>();

                // for (String url : jsonData) {
                for (int i = 0; i < jsonData.length; i++) {
                    JSONObject jObject = new JSONObject(jsonData[i]);

                    DirectionsJSONParser parser = new DirectionsJSONParser();

                    routes = (ArrayList<List<HashMap<String, String>>>) parser.parse(jObject);
                }
                return routes;
            } catch (Exception e) {
                Log.d("Background task", e.toString());
                return null; // Failed, return null
            }
        }

        @Override
        protected void onPostExecute(ArrayList<List<HashMap<String, String>>> result) {
            if (result.size() < 1) {
                Toast.makeText(DonarList.this, "No Points", Toast.LENGTH_LONG).show();
                return;
            }

            for (int i = 0; i < result.size(); i++) {

                List<HashMap<String, String>> path = result.get(i);
                String distance = "No distance";

                for (int j = 0; j < path.size(); j++) {
                    HashMap<String, String> point = path.get(j);

                    if (j == 0) {
                        distance = point.get("distance");
                        continue;
                    }
                }

                Log.d("Distance: ", distance);
                Toast.makeText(DonarList.this, "Your Distance ya hy :" + distance, Toast.LENGTH_SHORT).show();

            }

我想在我的应用中通过步行和驾车来获取距离。我已经按行获取了距离，但是现在我想要确切的距离。我已阅读为Google帐户启用API密钥计费功能，我...

Answer 1

我曾经构建了一个应用程序，可以计算从我的位置到附近餐馆的宽度。 Google Maps API不会为您提供距离，但是您可以使用道路上的纬度/经度点并使用公式来计算距离。