checkNotNull(SENDER_ID, "SENDER_ID");

GCMRegistrar.checkDevice(this);
GCMRegistrar.checkManifest(this);

TextView mDisplay = (TextView) findViewById(R.id.display);

String regId = "";

if (!GCMRegistrar.isRegistered(this))
{
    mDisplay.setText("registering");
    GCMRegistrar.register(this, SENDER_ID);

    regId = GCMRegistrar.getRegistrationId(this);
    String url = "localhost/Google-Cloud-Messaging-Server-Test/registration.php?regId=" + regId;

    Log.i(TAG, "registration url: " + url);
    HttpRequest httprequest = new HttpRequest(url);
}
else
{
    regId = GCMRegistrar.getRegistrationId(this);

    mDisplay.setText(regId);
    Log.v(TAG, "Already registered");

    GCMRegistrar.unregister(this);
}

regId = GCMRegistrar.getRegistrationId(this);
String url = "localhost/Google-Cloud-Messaging-Server-Test/registration.php?regId=" + regId;

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.codeglue.google.cloud.messaging.test"
android:versionCode="1"
android:versionName="1.0" >

<uses-sdk
    android:minSdkVersion="10"
    android:targetSdkVersion="15" />

<permission
    android:name="com.codeglue.google.cloud.messaging.test.permission.C2D_MESSAGE"
    android:protectionLevel="signature" />

<uses-permission android:name="com.codeglue.google.cloud.messaging.test.permission.C2D_MESSAGE" />
<uses-permission android:name="android.permission.GET_ACCOUNTS" />
<uses-permission android:name="android.permission.WAKE_LOCK" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="com.google.android.c2dm.permission.RECEIVE" />

<application
    android:icon="@drawable/ic_launcher"
    android:label="@string/app_name" >

    <activity
        android:name=".MainActivity"
        android:label="@string/app_name" >

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

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

            <category android:name="com.codeglue.google.cloud.messaging.test" />
        </intent-filter>
    </receiver>

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

</application>

</manifest>

<uses-permission android:name="android.permission.INTERNET"/>
     <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
     <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
     <uses-permission android:name="android.permission.GET_ACCOUNTS"/>
<uses-permission android:name="android.permission.WAKE_LOCK"/>
<permission
    android:name="you_package_name.permission.C2D_MESSAGE"
    android:protectionLevel="signature" />
<uses-permission
    android:name="you_package_name.permission.C2D_MESSAGE" />
<!-- This app has permission to register and receive data message. -->
<uses-permission
    android:name="com.google.android.c2dm.permission.RECEIVE" />

<receiver
        android:name="com.google.android.gcm.GCMBroadcastReceiver"
        android:permission="com.google.android.c2dm.permission.SEND" >
        <intent-filter>
            <!-- Receives the actual messages. -->
            <action android:name="com.google.android.c2dm.intent.RECEIVE" />
            <!-- Receives the registration id. -->
            <action android:name="com.google.android.c2dm.intent.REGISTRATION" />
            <category android:name="you_package_name" />
         </intent-filter>
    </receiver>