Java tutorial
/* * Copyright 2010 Facebook, 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.heraldapp.share.facebook; import java.io.BufferedReader; import java.io.FileNotFoundException; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.net.HttpURLConnection; import java.net.MalformedURLException; import java.net.SocketTimeoutException; import java.net.URL; import org.json.JSONException; import org.json.JSONObject; import android.app.AlertDialog.Builder; import android.content.Context; import android.os.Bundle; import android.webkit.CookieManager; import android.webkit.CookieSyncManager; /** * Utility class supporting the Facebook Object. * * @author ssoneff@facebook.com * */ public final class Util { public static String encodeUrl(Bundle parameters) { if (parameters == null) return ""; StringBuilder sb = new StringBuilder(); boolean first = true; for (String key : parameters.keySet()) { if (first) first = false; else sb.append("&"); sb.append(key + "=" + parameters.getString(key)); } return sb.toString(); } public static Bundle decodeUrl(String s) { Bundle params = new Bundle(); if (s != null) { String array[] = s.split("&"); for (String parameter : array) { String v[] = parameter.split("="); params.putString(v[0], v[1]); } } return params; } /** * Parse a URL query and fragment parameters into a key-value bundle. * * @param url * the URL to parse * @return a dictionary bundle of keys and values */ public static Bundle parseUrl(String url) { // hack to prevent MalformedURLException url = url.replace("fbconnect", "http"); try { URL u = new URL(url); Bundle b = decodeUrl(u.getQuery()); b.putAll(decodeUrl(u.getRef())); return b; } catch (MalformedURLException e) { return new Bundle(); } } /** * Connect to an HTTP URL and return the response as a string. * * Note that the HTTP method override is used on non-GET requests. (i.e. * requests are made as "POST" with method specified in the body). * * @param url * - the resource to open: must be a welformed URL * @param method * - the HTTP method to use ("GET", "POST", etc.) * @param params * - the query parameter for the URL (e.g. access_token=foo) * @return the URL contents as a String * @throws MalformedURLException * - if the URL format is invalid * @throws IOException * - if a network problem occurs */ public static String openUrl(String url, String method, Bundle params) throws MalformedURLException, IOException { if (method.equals("GET")) { url = url + "?" + encodeUrl(params); } String response = ""; HttpURLConnection conn = null; try { conn = (HttpURLConnection) new URL(url).openConnection(); conn.setRequestProperty("User-Agent", System.getProperties().getProperty("http.agent") + " FacebookAndroidSDK"); conn.setReadTimeout(10000); conn.setConnectTimeout(10000); if (!method.equals("GET")) { // use method override params.putString("method", method); conn.setRequestMethod("POST"); conn.setDoOutput(true); conn.getOutputStream().write(encodeUrl(params).getBytes("UTF-8")); } response = read(conn.getInputStream()); } catch (FileNotFoundException e) { // Error Stream contains JSON that we can parse to a FB error response = read(conn.getErrorStream()); } catch (SocketTimeoutException e) { return response; } return response; } private static String read(InputStream in) throws IOException { StringBuilder sb = new StringBuilder(); BufferedReader r = new BufferedReader(new InputStreamReader(in), 1000); for (String line = r.readLine(); line != null; line = r.readLine()) { sb.append(line); } in.close(); return sb.toString(); } public static void clearCookies(Context context) { // Edge case: an illegal state exception is thrown if an instance of // CookieSyncManager has not be created. CookieSyncManager is normally // created by a WebKit view, but this might happen if you start the // app, restore saved state, and click logout before running a UI // dialog in a WebView -- in which case the app crashes @SuppressWarnings("unused") CookieSyncManager cookieSyncMngr = CookieSyncManager.createInstance(context); CookieManager cookieManager = CookieManager.getInstance(); cookieManager.removeAllCookie(); } /** * Parse a server response into a JSON Object. This is a basic * implementation using org.json.JSONObject representation. More * sophisticated applications may wish to do their own parsing. * * The parsed JSON is checked for a variety of error fields and a * FacebookException is thrown if an error condition is set, populated with * the error message and error type or code if available. * * @param response * - string representation of the response * @return the response as a JSON Object * @throws JSONException * - if the response is not valid JSON * @throws FacebookError * - if an error condition is set */ public static JSONObject parseJson(String response) throws JSONException, FacebookError { // Edge case: when sending a POST request to /[post_id]/likes // the return value is 'true' or 'false'. Unfortunately // these values cause the JSONObject constructor to throw // an exception. if (response.equals("false")) { throw new FacebookError("request failed"); } if (response.equals("true")) { response = "{value : true}"; } JSONObject json = new JSONObject(response); // errors set by the server are not consistent // they depend on the method and endpoint if (json.has("error")) { JSONObject error = json.getJSONObject("error"); throw new FacebookError(error.getString("message"), error.getString("type"), 0); } if (json.has("error_code") && json.has("error_msg")) { throw new FacebookError(json.getString("error_msg"), "", Integer.parseInt(json.getString("error_code"))); } if (json.has("error_code")) { throw new FacebookError("request failed", "", Integer.parseInt(json.getString("error_code"))); } if (json.has("error_msg")) { throw new FacebookError(json.getString("error_msg")); } if (json.has("error_reason")) { throw new FacebookError(json.getString("error_reason")); } return json; } /** * Display a simple alert dialog with the given text and title. * * @param context * Android context in which the dialog should be displayed * @param title * Alert dialog title * @param text * Alert dialog message */ public static void showAlert(Context context, String title, String text) { Builder alertBuilder = new Builder(context); alertBuilder.setTitle(title); alertBuilder.setMessage(text); alertBuilder.create().show(); } }