Question

我有一个JSON文件，其中包含一个城市的数据，其中包含所有道路的名称和编号。我正在使用搜索引擎为该城市开发地图。如何在Android Studio应用中添加此文件并在两个位置之间实现搜索？

 {
   "type": "FeatureCollection",
   "crs": {
      "type": "name",
      "properties": {
         "name": "urn:ogc:def:crs:OGC:1.3:CRS84"
      }
   },
   "features": [
      {
         "type": "Feature",
         "properties": {
            "Name": "yes",
            "description": "",
            "timestamp": null,
            "begin": null,
            "end": null,
            "altitudeMode": null,
            "tessellate": -1,
            "extrude": 0,
            "visibility": -1,
            "drawOrder": null,
            "icon": null,
            "description_1": null,
            "Number": "10",
            "RoadNameCo": "03_10234",
            "RoadNameAL": "Person Nmae"
         },
         "geometry": {
            "type": "Point",
            "coordinates": [
               260.853835,
               426.601668,
               0
            ]
         }
     }
  }

Answer 1

首先，您必须将文件放在资源或原始文件夹中。

getResources（）则getIdentifier（＆＃34; FILENAME_WITHOUT_EXTENSION＆＃34 ;, ＆＃34; raw＆＃34;，getPackageName（））;

然后使用上面的行，您可以从原始文件夹中获取数据。之后，您可以从JSON获得所有位置点。

为此您可以使用此Async任务将该JSON解析为Points

private class ParserTask extends AsyncTask<String, Integer, List<List<HashMap<String, String>>>> {

    // Parsing the data in non-ui thread
    @Override
    protected List<List<HashMap<String,
            String>>> doInBackground(String... jsonData) {
        JSONObject jObject;
        List<List<HashMap<String, String>>> routes = null;
        try {
            jObject = new JSONObject(jsonData[0]);
            DataParser parser = new DataParser();
            // 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<HashMap<String, String>>> result) {
        ArrayList<LatLng> points;
        PolylineOptions lineOptions = null;

        // Traversing through all the routes
        for (int i = 0; i < result.size(); i++) {
            points = new ArrayList<>();
            lineOptions = new PolylineOptions();

            // Fetching i-th route
            List<HashMap<String, String>> path = result.get(i);

            // Fetching all the points in i-th route
            for (int j = 0; j < path.size(); j++) {
                HashMap<String, String> point = path.get(j);

                double lat = Double.parseDouble(point.get("lat"));
                double lng = Double.parseDouble(point.get("lng"));
                LatLng position = new LatLng(lat, lng);

                points.add(position);
            }

            // Adding all the points in the route to LineOptions
            lineOptions.addAll(points);
            lineOptions.width(10);
            lineOptions.color(Color.RED);
        }

        // Drawing polyline in the Google Map for the i-th route
        if (lineOptions != null) {
            mMap.addPolyline(lineOptions);
        }
    }
}

这是Data Parser类

公共类DataParser {

/**
 * Receives a JSONObject and returns a list of lists containing latitude and longitude
 */
public List<List<HashMap<String, String>>> parse(JSONObject jObject) {

    List<List<HashMap<String, String>>> routes = new ArrayList<>();
    JSONArray jRoutes;
    JSONArray jLegs;
    JSONArray jSteps;

    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<>();
            /** Traversing all legs */
            for (int j = 0; j < jLegs.length(); j++) {
                jSteps = ((JSONObject) jLegs.get(j)).getJSONArray("steps");
                /** 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);
                    /** Traversing all points */
                    for (int l = 0; l < list.size(); l++) {
                        HashMap<String, String> hm = new HashMap<>();
                        hm.put("lat", Double.toString((list.get(l)).latitude));
                        hm.put("lng", Double.toString((list.get(l)).longitude));
                        path.add(hm);
                    }
                }
                routes.add(path);
            }
        }

    } catch (JSONException e) {
        e.printStackTrace();
    } catch (Exception e) {
        e.getMessage();
    }


    return routes;
}


/**
 * 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<>();
    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;
}

}

将JSON数据添加到Android Studio地图

1 个答案: