Plotting markers on a map in Android using data from a JSON web service and the Google Maps Android API v2

MainActivity.java

/*
 * Copyright (c) 2013 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
 * in compliance with the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License
 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
 * or implied. See the License for the specific language governing permissions and limitations under
 * the License.
 */

package com.example.google.maps.demo;

import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;

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

import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.util.Log;

import java.io.IOException;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;

/**
 * @author saxman
 */
public class MainActivity extends FragmentActivity {
    private static final String LOG_TAG = "ExampleApp";

    private static final String SERVICE_URL = "YOUR DRIVE SERVICE URL";

    protected GoogleMap map;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        setUpMapIfNeeded();
    }

    @Override
    protected void onResume() {
        super.onResume();
        setUpMapIfNeeded();
    }

    private void setUpMapIfNeeded() {
        if (map == null) {
            map = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map))
                    .getMap();
            if (map != null) {
                setUpMap();
            }
        }
    }

    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);
            map.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)
                 ))
            );
        }
    }
}

You should have added an example.json structure somewhere. Would be awesome :)

https://gist.github.com/TimPim/5902100 Look in the comment at the begining. There you have a JSON

the problem I faced is that:

my json file will be updated hourly, and i read cached json file always.

how can I read updated raw json (ascii) file from GDrive?

For me it only displays the marker of the first 18 objects in the json file. It doesnt display more than 18 markers. How to solve this?

this worked fine for me!!!but i am facing the same problem with jbridge.What if my json is updated hourly??i need to update the markers

how to map json data with weblayout response, for eg: if i took firstname from weblayout and mapping the value from text file (file holding jsondata)

@jackbillstrom Hey am working on something Similar to this but am passing a delivery note number in an edittext in another activity that finds a builds a string url that fetches the json data with the coordinates , the problem is that i cant move data from the activity with the edit text to the map in another activity

In line 61 what is .getMap() ?