import com.google.android.apps.iosched.gcm.ServerUtilities; //导入依赖的package包/类
private void notifyGcmDevices() {
    String plusID = AccountUtils.getPlusProfileId(getApplicationContext());
    if (plusID != null) {
        LOGI(TAG, "Sending device sync notification");
        AndroidHttpClient httpClient = new AndroidHttpClient(Config.GCM_SERVER_URL);
        httpClient.setMaxRetries(1);
        ParameterMap params = httpClient.newParams()
                .add("key", Config.GCM_API_KEY)
                .add("squelch", ServerUtilities.getGcmId(this));
        String path = "/send/" + plusID + "/sync_user";
        httpClient.post(path, params, new AsyncCallback() {
            @Override
            public void onComplete(HttpResponse httpResponse) {
                LOGI(TAG, "Device sync notification sent");
            }

            @Override
            public void onError(Exception e) {
                LOGW(TAG, "Device sync notification failed", e);
            }
        });


    } else {
        LOGI(TAG, "No gPlusID, skipping device sync notification");
    }
}
 

import com.google.android.apps.iosched.gcm.ServerUtilities; //导入依赖的package包/类
public static void signOut(final Context context) {
    // Sign out of GCM message router
    ServerUtilities.onSignOut(context);

    // Destroy auth tokens
    invalidateAuthToken(context);

    // Remove remaining application state
    SharedPreferences sp = PreferenceManager.getDefaultSharedPreferences(context);
    sp.edit().clear().commit();
    context.getContentResolver().delete(ScheduleContract.BASE_CONTENT_URI, null, null);
}
 

import com.google.android.apps.iosched.gcm.ServerUtilities; //导入依赖的package包/类
private void registerGCMClient() {
    GCMRegistrar.checkDevice(this);
    if (BuildConfig.DEBUG) {
        GCMRegistrar.checkManifest(this);
    }

    final String regId = GCMRegistrar.getRegistrationId(this);

    if (TextUtils.isEmpty(regId)) {
        // Automatically registers application on startup.
        GCMRegistrar.register(this, Config.GCM_SENDER_ID);

    } else {
        // Device is already registered on GCM, check server.
        if (GCMRegistrar.isRegisteredOnServer(this)) {
            // Skips registration
            LOGI(TAG, "Already registered on the GCM server");

        } else {
            // Try to register again, but not on the UI thread.
            // It's also necessary to cancel the task in onDestroy().
            mGCMRegisterTask = new AsyncTask<Void, Void, Void>() {
                @Override
                protected Void doInBackground(Void... params) {
                    boolean registered = ServerUtilities.register(HomeActivity.this, regId);
                    if (!registered) {
                        // At this point all attempts to register with the app
                        // server failed, so we need to unregister the device
                        // from GCM - the app will try to register again when
                        // it is restarted. Note that GCM will send an
                        // unregistered callback upon completion, but
                        // GCMIntentService.onUnregistered() will ignore it.
                        GCMRegistrar.unregister(HomeActivity.this);
                    }
                    return null;
                }

                @Override
                protected void onPostExecute(Void result) {
                    mGCMRegisterTask = null;
                }
            };
            mGCMRegisterTask.execute(null, null, null);
        }
    }
}
 

import com.google.android.apps.iosched.gcm.ServerUtilities; //导入依赖的package包/类
private void registerGCMClient() {
    GCMRegistrar.checkDevice(this);
    GCMRegistrar.checkManifest(this);

    final String regId = GCMRegistrar.getRegistrationId(this);

    if (TextUtils.isEmpty(regId)) {
        // Automatically registers application on startup.
        GCMRegistrar.register(this, Config.GCM_SENDER_ID);

    } else {
        // Device is already registered on GCM, needs to check if it is
        // registered on our server as well.
        if (ServerUtilities.isRegisteredOnServer(this)) {
            // Skips registration.
            LOGI(TAG, "Already registered on the C2DM server");
        } else {
            // Try to register again, but not in the UI thread.
            // It's also necessary to cancel the thread onDestroy(),
            // hence the use of AsyncTask instead of a raw thread.
            mGCMRegisterTask = new AsyncTask<Void, Void, Void>() {
                @Override
                protected Void doInBackground(Void... params) {
                    boolean registered = ServerUtilities.register(HomeActivity.this, regId);
                    // At this point all attempts to register with the app
                    // server failed, so we need to unregister the device
                    // from GCM - the app will try to register again when
                    // it is restarted. Note that GCM will send an
                    // unregistered callback upon completion, but
                    // GCMIntentService.onUnregistered() will ignore it.
                    if (!registered) {
                        GCMRegistrar.unregister(HomeActivity.this);
                    }
                    return null;
                }

                @Override
                protected void onPostExecute(Void result) {
                    mGCMRegisterTask = null;
                }
            };
            mGCMRegisterTask.execute(null, null, null);
        }
    }
}