Android C2DM学习——云端推送

一．基础知识

当我们开发需要和服务器交互的应用程序时，基本上都需要获取服务器端的数据，比如《地震及时通》就需要及时获取服务器上最新的地震信息。要获取服务器上不定时更新的信息一般来说有两种方法，第一种是客户端使用Pull（拉）的方式，隔一段时间就去服务器上获取信息，看是否有更新的信息出现。第二种就是服务器使用Push（推送）的方式，当服务器端有新信息了，则把最新的信息Push到客户端上。

虽然Pull和Push两种方式都能实现获取服务器端更新信息的功能，但是明显来说Push is better than pull。因为Pull方式更费客户端的网络流量，更主要的是费电量。

Android从2.2版本开始增加了Cloud to Device Messaging（C2DM）框架，在系统中支持了Push功能，基于Android平台使用Push功能更加简单了。虽然C2DM目前还处在实验室阶段，不过小规模的使用应该没问题

下面我们就来体验一下Android的C2DM功能。

二．C2DM框架

使用Android的C2DM功能有几个要求：

1.       需要Android2.2及以上的系统版本。

2.       使用C2DM功能的Android设备上需要设置好Google的账户。

3.       需要在这里注册使用C2DM功能的用户邮箱账号（最好为C2DM单独注册一个Gmail邮箱账号）。

我们接下来C2DM的一个完整过程，这里借用一下Google官方推出的Chrome To Phone过程图来说明下。

图1 C2DM操作过程图

要使用C2DM来进行Push操作，基本上要使用以下6个步骤：

         （1）注册：Android设备把使用C2DM功能的用户账户（比如[email protected]）和App名称发送给C2DM服务器。

         （2）C2DM服务器会返回一个registration_id值给Android设备，设备需要保存这个registration_id值。

         （3）Android设备把获得的registration_id和C2DM功能的用户账户（[email protected]）发送给自己的服务器，不过一般用户账户信息因为和服务器确定好的，所以不必发送。

这样Android设备就完成了C2DM功能的注册过程，接下来就可以接收C2DM服务器Push过来的消息了。

         （4）服务器获得数据。这里图中的例子Chrome To Phone，服务器接收到Chrome浏览器发送的数据。数据也可以是服务器本地产生的。这里的服务器是Google AppEngine（很好的一项服务，可惜在国内被屏了），要换成自己的服务器。服务器还要获取注册使用C2DM功能的用户账户（[email protected]）的ClientLogin权限Auth。

         （5）服务器把要发送的数据和registration_id一起，并且头部带上获取的Auth，使用POST的方式发送给C2DM服务器。

         （6）C2DM服务器会以Push的方式把数据发送给对应的Android设备，Android设备只要在程序中按之前和服务器商量好的格式从对应的key中获取数据即可。

         这样我们就大概明白了C2DM的工作流程，下面我们就结合一个实例来具体的说明以上6个步骤。

三．实例开发

我们要创建的程序名称为AndroidC2DMDemo，包名为com.ichliebephone.c2dm。

开始之前我们先去C2DM网页上注册一下使用C2DM功能的用户账户。

图2 应用程序名

         其中应用程序名要填写带包名的完整名称，比如这里为om.ichliebephone.c2dm. AndroidC2DMDemo。

图3 C2DM用户账户注册

         这里的contact邮箱使用一个你能接收到邮件的邮箱即可，下面的Role（sender）account邮箱最好单独注册一个Gmail邮箱来使用C2DM服务。我们这里使用的是专门注册的[email protected]邮箱。

         提交后，过一段时间就会收到Google发送过来的确认邮件，然后你就可以使用C2DM的Push服务了。

        

介绍了这么多，我们先来快速完成一个实例，只完成Android设备端的注册部分，不包含向服务器发送registration_id和服务器向C2DM服务器发送数据的具体代码，这部分只是用Ubuntu下的curl命令来模拟，主要是快速亲自体验一下Push的结果。

创建一个Android工程AndroidC2DMDemo，并且包含进Google的开源例子Chrome To Phone中的c2dm包com.google.android.c2dm，包中包含三个Java类，分别为：

第一个类为C2DMBaseReceiver：

 /*
  * Copyright 2010 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.google.android.c2dm;

 import java.io.IOException;

 import android.app.AlarmManager;
 import android.app.IntentService;
 import android.app.PendingIntent;
 import android.content.Context;
 import android.content.Intent;
 import android.os.PowerManager;
 import android.util.Log;

 /**
  * Base class for C2D message receiver. Includes constants for the
  * strings used in the protocol.
  */
 /**
  * 接收和处理C2DM消息的基类
  * */
 public abstract class C2DMBaseReceiver extends IntentService {
     //和C2DM Push的Intent内容相关
     //重新向C2DM服务器注册
     private static final String C2DM_RETRY = "com.google.android.c2dm.intent.RETRY";
     //向C2DM服务器注册后的回调处理
     public static final String REGISTRATION_CALLBACK_INTENT = "com.google.android.c2dm.intent.REGISTRATION";
     //接收到C2DM服务器的推送消息
     private static final String C2DM_INTENT = "com.google.android.c2dm.intent.RECEIVE";

     // Logging tag
     private static final String TAG = "C2DM";

     // Extras in the registration callback intents.
     //向C2DM注册返回的intent中包含的key
     public static final String EXTRA_UNREGISTERED = "unregistered";
     public static final String EXTRA_ERROR = "error";
     public static final String EXTRA_REGISTRATION_ID = "registration_id";
     //向C2DM注册出错的原因
     public static final String ERR_SERVICE_NOT_AVAILABLE = "SERVICE_NOT_AVAILABLE";
     public static final String ERR_ACCOUNT_MISSING = "ACCOUNT_MISSING";
     public static final String ERR_AUTHENTICATION_FAILED = "AUTHENTICATION_FAILED";
     public static final String ERR_TOO_MANY_REGISTRATIONS = "TOO_MANY_REGISTRATIONS";
     public static final String ERR_INVALID_PARAMETERS = "INVALID_PARAMETERS";
     public static final String ERR_INVALID_SENDER = "INVALID_SENDER";
     public static final String ERR_PHONE_REGISTRATION_ERROR = "PHONE_REGISTRATION_ERROR";

     // wakelock
     private static final String WAKELOCK_KEY = "C2DM_LIB";

     private static PowerManager.WakeLock mWakeLock;
     private final String senderId;

     /**
      * The C2DMReceiver class must create a no-arg constructor and pass the
      * sender id to be used for registration.
      */
     public C2DMBaseReceiver(String senderId) {
         // senderId is used as base name for threads, etc.
         super(senderId);
         this.senderId = senderId;
     }
     //下面几个是接收到C2DM Push过来的信息后的回调函数，都可以在继承的子类中处理
     /**
      * Called when a cloud message has been received.
      */
     /**
      * 接收到C2DM服务器Push的消息后的回调函数，需要在继承的子类中处理
      * */
     protected abstract void onMessage(Context context, Intent intent);

     /**
      * Called on registration error. Override to provide better
      * error messages.
      *
      * This is called in the context of a Service - no dialog or UI.
      */
     /**
      * 出错的回调函数
      * */
     public abstract void onError(Context context, String errorId);

     /**
      * Called when a registration token has been received.
      */
     /**
      * 注册后的回调函数
      * */
     public void onRegistered(Context context, String registrationId) throws IOException {
         // registrationId will also be saved
     }

     /**
      * Called when the device has been unregistered.
      */
     /**
      * 取消注册的回调函数
      * */
     public void onUnregistered(Context context) {
     }

     //IntentService的方法
     @Override
     public final void onHandleIntent(Intent intent) {
         try {
             Context context = getApplicationContext();
             if (intent.getAction().equals(REGISTRATION_CALLBACK_INTENT)) {
                 handleRegistration(context, intent);//处理注册后的回调
             } else if (intent.getAction().equals(C2DM_INTENT)) {
                 onMessage(context, intent);//处理C2DM Push消息的回调
             } else if (intent.getAction().equals(C2DM_RETRY)) {
                 C2DMessaging.register(context, senderId); //重新注册
             }
         } finally {
             //  Release the power lock, so phone can get back to sleep.
             // The lock is reference counted by default, so multiple
             // messages are ok.

             // If the onMessage() needs to spawn a thread or do something else,
             // it should use it's own lock.
             mWakeLock.release();
         }
     }


     /**
      * Called from the broadcast receiver.
      * Will process the received intent, call handleMessage(), registered(), etc.
      * in background threads, with a wake lock, while keeping the service
      * alive.
      */
     static void runIntentInService(Context context, Intent intent) {
         if (mWakeLock == null) {
             // This is called from BroadcastReceiver, there is no init.
             PowerManager pm =
                 (PowerManager) context.getSystemService(Context.POWER_SERVICE);
             mWakeLock = pm.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK,
                     WAKELOCK_KEY);
         }
         mWakeLock.acquire();

         // Use a naming convention, similar with how permissions and intents are
         // used. Alternatives are introspection or an ugly use of statics.
         String receiver = context.getPackageName() + ".C2DMReceiver";
         intent.setClassName(context, receiver);

         context.startService(intent);

     }

     //处理注册后的回调
     private void handleRegistration(final Context context, Intent intent) {
         final String registrationId = intent.getStringExtra(EXTRA_REGISTRATION_ID);
         String error = intent.getStringExtra(EXTRA_ERROR);
         String removed = intent.getStringExtra(EXTRA_UNREGISTERED);
         Log.v(TAG, "handleRegistration");
         //打印出接收到的registraton_id
         Log.v(TAG, "dmControl: registrationId = " + registrationId +
                 ", error = " + error + ", removed = " + removed);
         if (Log.isLoggable(TAG, Log.DEBUG)) {
             Log.d(TAG, "dmControl: registrationId = " + registrationId +
                 ", error = " + error + ", removed = " + removed);
         }
         if (removed != null) {
             // Remember we are unregistered
             C2DMessaging.clearRegistrationId(context);
             onUnregistered(context);
             return;
         } else if (error != null) {
             // we are not registered, can try again
             C2DMessaging.clearRegistrationId(context);
             // Registration failed
             Log.e(TAG, "Registration error " + error);
             onError(context, error);
             if ("SERVICE_NOT_AVAILABLE".equals(error)) {
                 long backoffTimeMs = C2DMessaging.getBackoff(context);

                 Log.d(TAG, "Scheduling registration retry, backoff = " + backoffTimeMs);
                 Intent retryIntent = new Intent(C2DM_RETRY);
                 PendingIntent retryPIntent = PendingIntent.getBroadcast(context,
                         0 /*requestCode*/, retryIntent, 0 /*flags*/);

                 AlarmManager am = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
                 am.set(AlarmManager.ELAPSED_REALTIME,
                         backoffTimeMs, retryPIntent);

                 // Next retry should wait longer.
                 backoffTimeMs *= 2;
                 C2DMessaging.setBackoff(context, backoffTimeMs);
             }
         } else {
             try {
                 onRegistered(context, registrationId);
                 C2DMessaging.setRegistrationId(context, registrationId);
             } catch (IOException ex) {
                 Log.e(TAG, "Registration error " + ex.getMessage());
             }
         }
     }
 }

 

第二个类为C2DMBroadcastReceiver：

 /*
  */
 package com.google.android.c2dm;

 import android.app.Activity;
 import android.content.BroadcastReceiver;
 import android.content.Context;
 import android.content.Intent;

 /**
  * Helper class to handle BroadcastReciver behavior.
  * - can only run for a limited amount of time - it must start a real service
  * for longer activity
  * - must get the power lock, must make sure it's released when all done.
  *
  */
 /**
  * 帮助类，帮忙处理BroadcastReciver过程
  * */
 public class C2DMBroadcastReceiver extends BroadcastReceiver {

     @Override
     public final void onReceive(Context context, Intent intent) {
         // To keep things in one place.
         C2DMBaseReceiver.runIntentInService(context, intent);
         setResult(Activity.RESULT_OK, null /* data */, null /* extra */);
     }
 }

 

第三个类为C2DMessaging：

 /*
  * Copyright 2010 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.google.android.c2dm;

 import android.app.PendingIntent;
 import android.content.Context;
 import android.content.Intent;
 import android.content.SharedPreferences;
 import android.content.SharedPreferences.Editor;

 /**
  * Utilities for device registration.
  *
  * Will keep track of the registration token in a private preference.
  */
 /**
  * 和注册相关的一些实用函数
  * */
 public class C2DMessaging {
     public static final String EXTRA_SENDER = "sender";
     public static final String EXTRA_APPLICATION_PENDING_INTENT = "app";
     public static final String REQUEST_UNREGISTRATION_INTENT = "com.google.android.c2dm.intent.UNREGISTER";
     public static final String REQUEST_REGISTRATION_INTENT = "com.google.android.c2dm.intent.REGISTER";
     public static final String LAST_REGISTRATION_CHANGE = "last_registration_change";
     public static final String BACKOFF = "backoff";
     public static final String GSF_PACKAGE = "com.google.android.gsf";  //GSF为GoogleServicesFramework.apk的缩写


     // package
     static final String PREFERENCE = "com.google.android.c2dm";

     private static final long DEFAULT_BACKOFF = 30000;

     /**
      * Initiate c2d messaging registration for the current application
      */
     public static void register(Context context,
             String senderId) {
         Intent registrationIntent = new Intent(REQUEST_REGISTRATION_INTENT);
         registrationIntent.setPackage(GSF_PACKAGE);
         registrationIntent.putExtra(EXTRA_APPLICATION_PENDING_INTENT,
                 PendingIntent.getBroadcast(context, 0, new Intent(), 0));
         registrationIntent.putExtra(EXTRA_SENDER, senderId);
         context.startService(registrationIntent);
         // TODO: if intent not found, notification on need to have GSF
     }

     /**
      * Unregister the application. New messages will be blocked by server.
      */
     public static void unregister(Context context) {
         Intent regIntent = new Intent(REQUEST_UNREGISTRATION_INTENT);
         regIntent.setPackage(GSF_PACKAGE);
         regIntent.putExtra(EXTRA_APPLICATION_PENDING_INTENT, PendingIntent.getBroadcast(context,
                 0, new Intent(), 0));
         context.startService(regIntent);
     }

     /**
      * Return the current registration id.
      *
      * If result is empty, the registration has failed.
      *
      * @return registration id, or empty string if the registration is not complete.
      */
     public static String getRegistrationId(Context context) {
         final SharedPreferences prefs = context.getSharedPreferences(
                 PREFERENCE,
                 Context.MODE_PRIVATE);
         String registrationId = prefs.getString("dm_registration", "");
         return registrationId;
     }

     public static long getLastRegistrationChange(Context context) {
         final SharedPreferences prefs = context.getSharedPreferences(
                 PREFERENCE,
                 Context.MODE_PRIVATE);
         return prefs.getLong(LAST_REGISTRATION_CHANGE, 0);
     }

     static long getBackoff(Context context) {
         final SharedPreferences prefs = context.getSharedPreferences(
                 PREFERENCE,
                 Context.MODE_PRIVATE);
         return prefs.getLong(BACKOFF, DEFAULT_BACKOFF);
     }

     static void setBackoff(Context context, long backoff) {
         final SharedPreferences prefs = context.getSharedPreferences(
                 PREFERENCE,
                 Context.MODE_PRIVATE);
         Editor editor = prefs.edit();
         editor.putLong(BACKOFF, backoff);
         editor.commit();

     }

     // package
     static void clearRegistrationId(Context context) {
         final SharedPreferences prefs = context.getSharedPreferences(
                 PREFERENCE,
                 Context.MODE_PRIVATE);
         Editor editor = prefs.edit();
         editor.putString("dm_registration", "");
         editor.putLong(LAST_REGISTRATION_CHANGE, System.currentTimeMillis());
         editor.commit();

     }

     // package
     static void setRegistrationId(Context context, String registrationId) {
         final SharedPreferences prefs = context.getSharedPreferences(
                 PREFERENCE,
                 Context.MODE_PRIVATE);
         Editor editor = prefs.edit();
         editor.putString("dm_registration", registrationId);
         editor.commit();

     }
 }

 

代码中已添加了部分中文注释，可以先大概了解下，等整个工程建立完了在一起解释。

然后创建我们自己的包com.ichliebephone.c2dm，包含两个类，一个是工程的入口AndroidC2DMDemo：

 package com.ichliebephone.c2dm;

 import com.google.android.c2dm.C2DMessaging;

 import android.app.Activity;
 import android.os.Bundle;
 import android.util.Log;

 public class AndroidC2DMDemo extends Activity {
     /** Called when the activity is first created. */
     private static final String TAG = "AndroidC2DMDemo";
     public static final String SENDER_ID = "[email protected]"; //使用C2DM服务的用户账户
     public static final String MESSAGE_KEY_ONE = "msg";   //和服务器商量好的接收消息的键值key

     @Override
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.main);

         Log.v(TAG, "Start");
         //向C2DM服务器注册
         C2DMessaging.register(this, SENDER_ID);
     }


 }

 

很简单，就是开始向C2DM服务器进行注册。

另一个类为C2DMBaseReceiver的子类C2DMReceiver：

 package com.ichliebephone.c2dm;

 import java.io.IOException;

 import android.app.Notification;
 import android.app.NotificationManager;
 import android.app.PendingIntent;
 import android.content.Context;
 import android.content.Intent;
 import android.os.Bundle;
 import android.util.Log;

 import com.google.android.c2dm.C2DMBaseReceiver;
 //接收C2DM服务器Push的消息，包括注册返回的registration_id消息，推送的数据消息等
 public class C2DMReceiver extends C2DMBaseReceiver{

     private static final String TAG="C2DMReceiver";
     //
     public C2DMReceiver()
     {
         super(AndroidC2DMDemo.SENDER_ID);
     }
     public C2DMReceiver(String senderId) {
         super(senderId);
         // TODO Auto-generated constructor stub
     }
     //接收到Push消息的回调函数
     @Override
     protected void onMessage(Context context, Intent intent) {
         // TODO Auto-generated method stub
         Log.v(TAG, "C2DMReceiver message");
         Bundle extras = intent.getExtras();
         if(extras!=null){
             String msg = (String)extras.get(AndroidC2DMDemo.MESSAGE_KEY_ONE);
             Log.v(TAG, "The received msg = "+msg);
             //在标题栏上显示通知
             NotificationManager notificationManager = (NotificationManager)getSystemService(NOTIFICATION_SERVICE);
             Notification notification = new Notification(R.drawable.icon, msg, System.currentTimeMillis());
             PendingIntent contentIntent = PendingIntent.getActivity(this, 0, new Intent(this, AndroidC2DMDemo.class), 0);
             notification.setLatestEventInfo(this, getString(R.string.app_name), msg, contentIntent);
             notificationManager.notify(0, notification);

         }
     }

     @Override
     public void onError(Context context, String errorId) {
         // TODO Auto-generated method stub
         Log.v(TAG, "C2DMReceiver error");
     }

     @Override
     public void onRegistered(Context context, String registrationId)
             throws IOException {
         // TODO Auto-generated method stub
         super.onRegistered(context, registrationId);
         Log.v(TAG, "C2DMReceiver Register");
     }
     @Override
     public void onUnregistered(Context context) {
         // TODO Auto-generated method stub
         super.onUnregistered(context);
         Log.v(TAG, "C2DMReceiver UnRegister");
     }
 }

 

在这个类中我们主要在接收到Push的回调函数onMessage中对消息进行了接收，并且使用Notification的方式显示在状态栏上。

我们完整的工程目录是这样的：

图4 工程目录

         最后我们还要在AndroidManifest.xml中增加对应的权限等内容:

 <?xml version="1.0" encoding="utf-8"?>
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
       package="com.ichliebephone.c2dm"
       android:versionCode="1"
       android:versionName="1.0">
     <uses-sdk android:minSdkVersion="8" />

     <!--Only this application can receive the message and registration result  -->
     <!-- 设置一个权限，使只有这个应用才能接收到对应Push的消息及注册时返回的结果  -->
     <permission android:name="com.ichliebephone.c2dm.permission.C2D_MESSAGE"
         android:protectionLevel="signature"></permission>
     <uses-permission android:name="com.ichliebephone.c2dm.permission.C2D_MESSAGE"/>
     <!-- This application has the permission to register and receive c2dm message -->
     <!-- 设置注册和接收C2DM Push消息的权限 -->
     <uses-permission android:name="com.google.android.c2dm.permission.RECEIVE" />
     <!-- Send and registration id to the server  -->
     <!-- 设置联网权限，在把registration_id发送给服务器的时候要用 -->
     <uses-permission android:name="android.permission.INTERNET" />
     <!-- App must have this permission to use the library -->
     <!-- 其他和获取手机中用户账户相关的权限 -->
     <uses-permission android:name="android.permission.WAKE_LOCK" />
     <uses-permission android:name="android.permission.GET_ACCOUNTS" />
     <uses-permission android:name="android.permission.USE_CREDENTIALS" />

     <application android:icon="@drawable/icon" android:label="@string/app_name">
         <activity android:name=".AndroidC2DMDemo"
                   android:label="@string/app_name">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />
                 <category android:name="android.intent.category.LAUNCHER" />
             </intent-filter>
         </activity>

         <!-- In order to use the c2dm library, an
              application must declare a class with the name C2DMReceiver, in its
              own package, extending com.google.android.c2dm.C2DMBaseReceiver
              It must also include this section in the manifest. -->
         <!-- 为了使用c2dm包com.google.android.c2dm及其对应的3个类，我们需要声明一个
             继承com.google.android.c2dm.C2DMBaseReceiver类的子类C2DMReceiver，
             并且要在这声明下 -->
         <service android:name=".C2DMReceiver" />

         <!-- Only google service can send data messages for the app. If permission is not set -
              any other app can generate it -->
         <!-- 谷歌的C2DM服务只为这个程序发送数据，声明对应的权限 -->
         <receiver android:name="com.google.android.c2dm.C2DMBroadcastReceiver"
                   android:permission="com.google.android.c2dm.permission.SEND">
             <!-- Receive the actual message -->
             <!-- 可以接收实际的Push数据 -->
             <intent-filter>
                 <action android:name="com.google.android.c2dm.intent.RECEIVE" />
                 <category android:name="com.ichliebephone.c2dm" />
             </intent-filter>
             <!-- Receive the registration id -->
             <!-- 可以接收注册后返回的registration_id -->
             <intent-filter>
                 <action android:name="com.google.android.c2dm.intent.REGISTRATION" />
                 <category android:name="com.ichliebephone.c2dm" />
             </intent-filter>
         </receiver>
     </application>
 </manifest>

 

因为C2DM功能只有2.2及以上的Android系统才支持，因此创建一个2.2及以上的AVD，然后在”设置->账户与同步”里还要设置好Google Account，如下图所示：

图5 设置Android设备中的Google账户

然后就可以运行程序了，我们会在DDMS输出中看到获得的registration_id：

图6 获得的registration_id

如果第一次运行没有出现，试着再运行一次。

有了registration_id，我们的服务器端就可以向C2DM端发送需要Push的数据了，这里进行简单化处理下，在Ubuntu下直接使用curl命令来模拟服务器功能向C2DM发送数据。

我们先来获取C2DM的ClientLogin权限Auth，在Ubuntu终端下输入：

 lingaohe@lingaohe-laptop:~$ curl -d "accountType=HOSTED_OR_GOOGLE&[email protected]&Passwd=androidc2dmdemo&service=ac2dm&source=bupt-c2dmdemo-1.0" https://www.google.com/accounts/ClientLogin

 

这个表示以POST的方式向https://www.google.com/accounts/ClientLogin发送数据，其中把Email和Passwd换成你自己在C2DM网页上注册的邮箱号和密码。

如果你的邮箱已在C2DM网页上注册，并且密码没有错误的话就会返回需要的Auth内容：

 SID=DQAAAKYAAADcTtHbBBNcZJEOfkfVRycD_ZOIidwsQ3UwIY7cSrYWaY6uhlfo0l9gRPB-mQxP4K2T5tWiG--vWVmSTeq5p8SPwgnsYvfzj7bkNiPPIy4xRimVVfBmAHnZgLohw7gHMKi5DS6kK-Ut5tNzdTkI0I2tUDF0ryQ7MnPpI6Sj-gUCyBXmvKatHHDnNTTV78XdGIx7FYej1DyqGsPsYo3bCstHgltjv3cd2Hs7D4yrpUWHZw
 LSID=DQAAAKgAAABCpaoUE4XvxM24Cofntw1IUGx5fKxX-m7aqTL0zhunP0OjzJ2sn9ywmPa1BMZ2cF2IchuxHFLVzaSQfydAmiHZJGXLgaUorpIN6yz1e0VFWKmS6j4wGjZOos3QoJ9rkha0jKbOiHfBesADjxk-qjJ24TJ0RL-xkZHQyzS69YlA1KyzqIKjAMCzgqaDfCwhqxylJzizJksO2h8xpAFXZ38d_grm8XYZtzejiCiAMAR65A
 Auth=DQAAAKoAAACRF4pgYULnXULoWgbwfdqmMiRhfZYa1l-LW_rwGD7cofov4L4c2bVrtCOXbEbkju_hhqdAonpMkrb5icptt28fU8c-s-u1y2MXNYDxPIdQzfA2t6oI3NTmyj35MpsR1NKL4TN7ZVEn6z9NueuiKAqLHukZYh1YMGkGC8M6rVvA7AWPW36064XCQED7KLVNp_pGT00lrni7UdZKZWEy0FT-EVR-OxDyHWw6C-5Kmfkisw

 

返回的内容包括SID，LSID和Auth三个部分，其中Auth是我们需要的内容。

有了Auth和registration_id值后，我们就可以继续用curl命令模拟我们自己服务器的功能向C2DM发送要推送的数据：

 lingaohe@lingaohe-laptop:~$ curl -H "Authorization:GoogleLogin auth=DQAAAKoAAACRF4pgYULnXULoWgbwfdqmMiRhfZYa1l-LW_rwGD7cofov4L4c2bVrtCOXbEbkju_hhqdAonpMkrb5icptt28fU8c-s-u1y2MXNYDxPIdQzfA2t6oI3NTmyj35MpsR1NKL4TN7ZVEn6z9NueuiKAqLHukZYh1YMGkGC8M6rVvA7AWPW36064XCQED7KLVNp_pGT00lrni7UdZKZWEy0FT-EVR-OxDyHWw6C-5Kmfkisw" -d "registration_id=APA91bGUBoSvt3G5Ny9t0IGLmIKAKYX6G6VHwSQHh3tP2fqcaQ0N4GPdKh5B3RDUHFCFF06YwT8ifOP_cOy5BAWyCLHL8d8NpuIW9AqXt9h2JSBVF2MitZA&collapse_key=1&data.msg=ichliebejiajia" https://android.apis.google.com/c2dm/send

 

其中发送的数据部分为data.msg=ichliebejiajia，表示发送的数据内容为ichliebejiajia，键值为msg，键值得和Android终端上的程序统一好，以便终端上可以获取。如果发送成功，会返回一个id值，比如：

 id=0:1308623423080544%6c5c15c200000031
 lingaohe@lingaohe-laptop:~$

 

这时我们的服务器就已经把数据发送给C2DM服务器了，Android设备上一会就能接收到C2DM服务器Push的数据。

在我们的例子中我们可以看到DDMS中打印出的消息：

图7 获取到的Push数据

同时Android模拟器的状态栏上会有对应的通知显示：

图8 Android模拟器接收到的Push数据

       这样我们就快速实现了下Android的C2DM框架的Push功能。进一步的具体解释说明及服务器端的代码处理我们以后再学习。

 

文章对应的完整代码例子下载地址：

http://download.csdn.net/source/3425855