我想实现一个gcm客户端到一个现有的android应用程序。所以，通过以下this教程，我写了以下代码：

public class RegisterForGCMAsyncTask extends AbstractSecureOperationTask {

...

@Override
protected Boolean doInBackground(String... params) {
    String token = authenticate();
    getRegId();
    if (TextUtils.isEmpty(registrationId)) {
        return false;
    }
    //
    try {
        URL url = convertToURLEscapingIllegalCharacters(String.format(Constants.REGISTER_URL,
                registrationId, userId, token));
        URLConnection connection = url.openConnection();
        InputStreamReader streamReader = new InputStreamReader(connection.getInputStream());
        JSONParser parser = new JSONParser();
        JSONObject rootObj = (JSONObject) parser.parse(streamReader);
        String status = rootObj.get("status").toString();
        if (status.equals("OK")) {
            return true;
        }
    } catch (ParseException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }
    return false;
}

private void getRegId() {
    try {
        if (gcm == null) {
            gcm = GoogleCloudMessaging.getInstance(context);
        }
        registrationId = gcm.register(PROJECT_ID);
    } catch (IOException e) {
        Log.e(LOG_TAG, e.getMessage(), e);
    }
}
}

安卓主节日：

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="de.xxxxxxxx.xxxxxxxx"
      android:versionCode="20140617"
      android:versionName="2.0.0">

<uses-sdk
        android:minSdkVersion="15"
        android:targetSdkVersion="19"/>

<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.GET_ACCOUNTS"/>
<uses-permission android:name="android.permission.WAKE_LOCK"/>
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<uses-permission android:name="com.google.android.c2dm.permission.RECEIVE"/>
<uses-permission android:name="com.google.android.providers.gsf.permission.READ_GSERVICES"/>

<permission
        android:name="de.xxxxxxxx.xxxxxxxx.permission.MAPS_RECEIVE"
        android:protectionLevel="signature"/>
<uses-permission android:name="de.xxxxxxxx.xxxxxxxx.permission.MAPS_RECEIVE"/>

<permission
        android:name="de.xxxxxxxx.xxxxxxxx.permission.C2D_MESSAGE"
        android:protectionLevel="signature"/>
<uses-permission android:name="de.xxxxxxxx.xxxxxxxx.permission.C2D_MESSAGE"/>

<!-- Maps API needs OpenGL ES 2.0. -->
<uses-feature
        android:glEsVersion="0x00020000"
        android:required="true"/>

<application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme">

    <activity
            android:name="de.retterapps.Handyalarm.views.activities.MainActivity"
            android:configChanges="orientation|screenLayout|screenSize|layoutDirection"
            android:label="@string/app_name"
            android:theme="@style/AppTheme">
        <intent-filter>
            <action android:name="android.intent.action.MAIN"/>

            <category android:name="android.intent.category.LAUNCHER"/>
        </intent-filter>
    </activity>

    <receiver
            android:name=".helper.gcm.GcmBroadcastReceiver"
            android:permission="com.google.android.c2dm.permission.SEND">
        <intent-filter>
            <action android:name="com.google.android.c2dm.intent.RECEIVE"/>
            <category android:name="de.xxxxxxxx.xxxxxxxx"/>
        </intent-filter>
    </receiver>
    <service android:name=".helper.gcm.GcmMessageHandler"/>

    <meta-data
            android:name="com.google.android.gms.version"
            android:value="@integer/google_play_services_version"/>
    <meta-data
            android:name="com.google.android.maps.v2.API_KEY"
            android:value="xxxxxxxx"/>
</application>

昨天一切正常，我可以检索注册ID。但现在，总是有一个IOException说SERVICE_NOT_AVAILABLE。
我在我的三星Galaxy S5和Genymotion模拟器（Android 4. 1. 2）上测试了它，但我得到的结果总是一样的。有人知道如何解决这个问题吗？

编辑

以下是完整的堆栈跟踪：

java.io.IOException: SERVICE_NOT_AVAILABLE
    at com.google.android.gms.gcm.GoogleCloudMessaging.register(Unknown Source)
    at de.retterapps.Handyalarm.helper.tasks.RegisterForGCMAsyncTask.getRegId(RegisterForGCMAsyncTask.java:72)
    at de.retterapps.Handyalarm.helper.tasks.RegisterForGCMAsyncTask.doInBackground(RegisterForGCMAsyncTask.java:43)
    at de.retterapps.Handyalarm.helper.tasks.RegisterForGCMAsyncTask.doInBackground(RegisterForGCMAsyncTask.java:24)
    at android.os.AsyncTask$2.call(AsyncTask.java:287)
    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
    at java.util.concurrent.FutureTask.run(FutureTask.java:137)
    at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
    at java.lang.Thread.run(Thread.java:856)