Java tutorial
/* * Copyright (C) 2011 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.partytv.server; import android.os.AsyncTask; import android.util.Log; import org.apache.http.HttpEntity; import org.apache.http.HttpResponse; import org.apache.http.client.HttpClient; import org.apache.http.client.methods.HttpGet; import org.apache.http.impl.client.DefaultHttpClient; import org.json.JSONArray; import org.json.JSONException; import org.json.JSONObject; import java.io.IOException; import java.net.URI; import java.net.URISyntaxException; import java.net.URLEncoder; /** * This class provides Geocoding services through the Google Maps APIs. */ public class GeoCoderTask extends AsyncTask<String, Void, GeoResponse> { // URL prefix to the geocoder private static final String GEOCODER_REQUEST_PREFIX_FOR_JSON = "//maps.googleapis.com/maps/api/geocode/json"; private static final String TAG = null; public GeoResponse geocode(String address) throws IOException, URISyntaxException, JSONException { // prepare a URL to the geocoder String url = GEOCODER_REQUEST_PREFIX_FOR_JSON + "?address=" + URLEncoder.encode(address, "UTF-8") + "&sensor=false"; // prepare an HTTP connection to the geocoder URI uri = new URI("http", url, null); HttpGet get = new HttpGet(uri); HttpClient client = new DefaultHttpClient(); HttpResponse response = client.execute(get); HttpEntity entity = response.getEntity(); String str = Utilities.convertStreamToString(entity.getContent()); JSONObject json = new JSONObject(str); return parse(json); } private GeoResponse parse(JSONObject json) { GeoResponse geoResponse = null; try { JSONArray array = json.getJSONArray("results"); if (array.length() > 0) { JSONObject obj = array.getJSONObject(0); JSONObject viewport = obj.getJSONObject("geometry").getJSONObject("viewport"); double minLat = viewport.getJSONObject("southwest").getDouble("lat"); double minLng = viewport.getJSONObject("southwest").getDouble("lng"); double maxLat = viewport.getJSONObject("northeast").getDouble("lat"); double maxLng = viewport.getJSONObject("northeast").getDouble("lng"); geoResponse = new GeoResponse(minLat, minLng, maxLat, maxLng); } } catch (JSONException e) { Log.e(TAG, e.toString()); } return geoResponse; } /** * The system calls this to perform work in a worker thread and delivers it * the parameters given to AsyncTask.execute() */ protected GeoResponse doInBackground(String... address) { try { return geocode(address[0]); } catch (IOException e) { e.printStackTrace(); } catch (URISyntaxException e) { e.printStackTrace(); } catch (JSONException e) { e.printStackTrace(); } return null; } }