android - GCMRegistrar.getRegistrationId(this)始终返回空字符串(使用GCM的Android Push通知)

 public void registerClient()
 {
  try
  {
   // Check that the device supports GCM (should be in a try / catch)
   GCMRegistrar.checkDevice(this);

   // Check the manifest to be sure this app has all the required
   // permissions.
   GCMRegistrar.checkManifest(this);

   // Get the existing registration id, if it exists.
   regId = GCMRegistrar.getRegistrationId(this);

   if (regId.equals(""))
   {

    // register this device for this project
    GCMRegistrar.register(this, PROJECT_ID);
    regId = GCMRegistrar.getRegistrationId(this);

regId = GCMRegistrar.getRegistrationId（this）;总是返回一个空字符串。是否已弃用GCMRegister类？
我从sdk / extras / google / gcm / gcm-client路径添加了gcm jar。
我也尝试添加Google Play服务库并执行代码（删除了gcm.jar），但随后显示GCMRegistrar类未找到异常
我已经检查了所有权限，它们似乎是正确的。
这是我的清单文件

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.gcmclient"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="14"
        android:targetSdkVersion="19" />

    <!-- receives GCM messages -->
    <uses-permission android:name="com.google.android.c2dm.permission.RECEIVE" />
    <!-- GCM connects to Google services -->
    <uses-permission android:name="android.permission.INTERNET" />

    <!-- GCM requires a Google account -->
    <uses-permission android:name="android.permission.GET_ACCOUNTS" />
    <uses-permission android:name="android.permission.USE_CREDENTIALS" />
    <uses-permission android:name="android.permission.READ_OWNER_DATA" />

    <!-- wake the processor if a GCM message is received -->
    <uses-permission android:name="android.permission.WAKE_LOCK" />

    <permission
        android:name="com.example.gcmclient.permission.C2D_MESSAGE"
        android:protectionLevel="signature" >
    </permission>

    <uses-permission android:name="com.example.gcmclient.permission.C2D_MESSAGE" />

    <application
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name=".MainActivity"
            android:label="@string/title_activity_main" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

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

        <receiver
            android:name=".GCMBroadcastReceiver"
            android:permission="com.google.android.c2dm.permission.SEND" >
            <intent-filter>
                <action android:name="com.google.android.c2dm.intent.RECEIVE" />

                <category android:name="com.example.gcmclient" />

                <action android:name="com.google.android.c2dm.intent.REGISTRATION" />

                <category android:name="com.example.gcmclient" />
            </intent-filter>
        </receiver>

        <service android:name=".GCMIntentService" >
        </service>
    </application>

</manifest>

最佳答案

您的代码看起来还可以，但是使用GCM时，您必须同步设置中的帐户。按照步骤。

转到设置--->添加帐户--->谷歌