Created BroadcastReceiver that kicks the C2DM/GCM update process when the app is upgraded

android/AndroidManifest.xml

@@ -79,6 +79,17 @@
             </intent-filter>
         </receiver>
 
+        <!-- 
+          Receiver called when the application is updated (Android 3.1+), it will check
+          if the previous version used C2DM and update to GCM if necessary.
+          -->
+        <receiver
+            android:name=".Updater">
+            <intent-filter>
+                <action android:name="android.intent.action.MY_PACKAGE_REPLACED" />
+            </intent-filter>
+        </receiver>
+
         <receiver android:name=".UserPresentReceiver" android:enabled="false">
             <intent-filter>
                 <action android:name="android.intent.action.USER_PRESENT" />

android/src/com/google/android/apps/chrometophone/DeviceRegistrar.java

@@ -150,4 +150,22 @@ public class DeviceRegistrar {
         Configuration config = context.getResources().getConfiguration();
         return (config.screenLayout & xlargeBit) == xlargeBit;
     }
+
+    /**
+     * Update the device to use GCM instead of C2DM.
+     */
+    static boolean updateC2DM(Context context) {
+        SharedPreferences prefs = Prefs.get(context);
+        String c2dmRegId = prefs.getString("deviceRegistrationID", null);
+        // The old versions of the app that used C2DM stored the registration id in the default
+        // preferences; the new version stores it in the GCM library.
+        if (c2dmRegId != null) {
+            Log.i(TAG, "Updating from C2DM to GCM");
+            DeviceRegistrar.unregisterWithServer(context, c2dmRegId, "ac2dm");
+            GCMRegistrar.register(context, DeviceRegistrar.SENDER_ID);
+            return true;
+        } else {
+            return false;
+        }
+    }
 }

android/src/com/google/android/apps/chrometophone/HistoryActivity.java

@@ -44,14 +44,8 @@ public class HistoryActivity extends Activity implements OnChildClickListener {
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
 
-        SharedPreferences prefs = Prefs.get(this);
+        boolean isGcmUpdate = DeviceRegistrar.updateC2DM(this);
-        String c2dmRegId = prefs.getString("deviceRegistrationID", null);
+        if (!isGcmUpdate) {
-        if (c2dmRegId != null) {
-            // this is an update from the version that uses C2DM: must
-            // unregister and register again using GCM
-            DeviceRegistrar.unregisterWithServer(this, c2dmRegId, "ac2dm");
-            GCMRegistrar.register(this, DeviceRegistrar.SENDER_ID);
-        } else {
             // Run the setup first if necessary
             String gcmRegId = GCMRegistrar.getRegistrationId(this);
             if (gcmRegId.equals("")) {

android/src/com/google/android/apps/chrometophone/Updater.java

@@ -0,0 +1,22 @@
+package com.google.android.apps.chrometophone;
+
+import android.content.BroadcastReceiver;
+import android.content.Context;
+import android.content.Intent;
+import android.util.Log;
+
+/**
+ * Receiver called when the application is updated (Android 3.1+), it will check
+ * if the previous version used C2DM and, if so, update to GCM.
+ */
+public class Updater extends BroadcastReceiver {
+
+    private static final String TAG = "Updater";
+
+    @Override
+    public void onReceive(Context context, Intent intent) {
+        Log.d(TAG, "onReceive(" + intent + ")");
+        DeviceRegistrar.updateC2DM(context);
+    }
+    
+}