Android在谷歌地图上显示json数据。正在显示标记

Question

我需要在谷歌地图上显示json数据。

我的问题是它只在谷歌地图上加载了一个json数组，而另一个则没有加载。当我关闭应用程序并再次打开时，它也没有显示任何标记。这是我的代码

 @Override
    public void onMapReady(GoogleMap googleMap) {
        mMap = googleMap;

        setUpMap();
    }

here i'm loading service call.

private void setUpMap() {
        // Retrieve the city data from the web service
        // In a worker thread since it's a network operation.
        new Thread(new Runnable() {
            public void run() {
                try {
                    retrieveAndAddCities();
                } catch (IOException e) {
                    Log.e(LOG_TAG, "Cannot retrive cities", e);
                    return;
                }
            }
        }).start();
    }

 protected void retrieveAndAddCities() throws IOException {
        HttpURLConnection conn = null;
        final StringBuilder json = new StringBuilder();
        try {
            // Connect to the web service
            URL url = new URL(SERVICE_URL);
            conn = (HttpURLConnection) url.openConnection();
            InputStreamReader in = new InputStreamReader(conn.getInputStream());

            // Read the JSON data into the StringBuilder
            int read;
            char[] buff = new char[1024];
            while ((read = in.read(buff)) != -1) {
                json.append(buff, 0, read);
            }
        } catch (IOException e) {
            Log.e(LOG_TAG, "Error connecting to service", e);
            throw new IOException("Error connecting to service", e);
        } finally {
            if (conn != null) {
                conn.disconnect();
            }
        }

        // Create markers for the city data.
        // Must run this on the UI thread since it's a UI operation.
        runOnUiThread(new Runnable() {
            public void run() {
                try {
                    createMarkersFromJson(json.toString());
                } catch (JSONException e) {
                    Log.e(LOG_TAG, "Error processing JSON", e);
                }
            }
        });
    }

    void createMarkersFromJson(String json) throws JSONException {
        // De-serialize the JSON string into an array of city objects
        JSONArray jsonArray = new JSONArray(json);
        for (int i = 0; i < jsonArray.length(); i++) {
            // Create a marker for each city in the JSON data.
            JSONObject jsonObj = jsonArray.getJSONObject(i);
            System.out.println("ben:"+jsonObj);
            mMap.addMarker(new MarkerOptions()
                    .title(jsonObj.getString("name"))
                    .snippet(Integer.toString(jsonObj.getInt("population")))
                    .position(new LatLng(
                            jsonObj.getJSONArray("latlng").getDouble(0),
                            jsonObj.getJSONArray("latlng").getDouble(1)
                    ))
            );
        }
1s when i load google maps its loading only one location from json array. when i close the app and open again it will not load any location.

i have multiple location from json service but it load only one location on google maps. dont know what is issues.

I am using this example as a reference.

https://gist.github.com/TimPim/5902100

This my service 

[ { "name": "John Doe", "latlng": [ 62.457434, 17.349869 ], "population": "123" }, { "name": "Jane Doe", "latlng": [ 62.455102, 17.345599 ], "population": "132" }, { "name": "James Bond", "latlng": [ 62.458287, 17.356306 ], "population": "123" } ]

任何人都可以提供示例代码。如果我从后台更改此服务，则不会在谷歌地图上显示任何内容。