MainActivity.java

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        RichNotifications.onNewIntent(this, getIntent());
    }

    @Override
    protected void onResume() {
        super.onResume();

        // Check for Google Services + register for Remote Notifications
        RichNotifications.checkForGoogleServicesAndRegister(this, "jhondoe");
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        RichNotifications.onActivityResult(this, requestCode, resultCode);
    }

    @Override
    protected void onNewIntent(Intent intent) {
        super.onNewIntent(intent);
        RichNotifications.onNewIntent(this, intent);
    }

Manifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.test.app">

    <uses-permission android:name="android.permission.WAKE_LOCK" />
    <uses-permission android:name="android.permission.INTERNET" />
    <!-- Required to handle connectivity change event -->
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

    <permission
        android:name="com.test.app.permission.C2D_MESSAGE"
        android:protectionLevel="signature" />

    <uses-permission android:name="com.test.app.permission.C2D_MESSAGE" />

    <application
        android:name=".MyApp"
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">

        <activity android:name="com.test.app.MainActivity">
            <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.gms.gcm.GcmReceiver"
            android:exported="true"
            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.test.app" />
            </intent-filter>
        </receiver>

        <service
            android:name="app.test.richnotifications.InstanceIDService"
            android:exported="false">
            <intent-filter>
                <action android:name="com.google.android.gms.iid.InstanceID" />
            </intent-filter>
        </service>

        <service
            android:name="app.test.richnotifications.RegistrationIntentService"
            android:exported="false" />

        <receiver android:name="app.test.richnotifications.ConnectivityChangeListener">
            <intent-filter>
                <action android:name="android.net.conn.CONNECTIVITY_CHANGE" />
            </intent-filter>
        </receiver>

        <service
            android:name="app.test.richnotifications.GCMListener"
            android:exported="false">
            <intent-filter>
                <action android:name="com.google.android.c2dm.intent.RECEIVE" />
            </intent-filter>
        </service>

    </application>

</manifest>

MyApp.java

public class MyApp extends Application {
    @Override
    public void onCreate() {
        super.onCreate();

        // Provide Activity class which should be launched, API key & secret, GCM sender ID, notification icon
        RichNotifications.configure(getCacheDir(), MainActivity.class,
                getString(R.string.API_KEY), getString(R.string.API_SECRET),
                getString(R.string.gcm_defaultSenderId), R.drawable.ic_notification_small);
    }
}

strings.xml

<resources>
    <string name="API_KEY">a94a8fe5ccb19ba61c4c0873d391e987982fbbd3</string>
    <string name="API_SECRET">99efc50a9206bde3d7a8e694aad8e138ca7dc3f7</string>
</resources>