Migrating to FCM from GCM

As you know Google introduced the new FCM (Firebase Cloud Messaging) as an upgrade to GCM, Its not mandatory to update your app to FCM as the GCM is still functional and the update is not affecting it. But

its recommended to upgrade so that you can get the new features. And for the new apps I’ll recommend to use FCM. So lets start migration our existing android app to FCM.

Firstly import your project to Firebase console and provide the package name and SHA-1. Then download the new google-services.json file and replace it with your existing file in your project.

Please note that now you don’t need any kind of permission in your manifest like in GCM so remove all the GCM related permissions from manifest file. In the app level gradle file change the dependency from

compile "com.google.android.gms:play-services-gcm:8.4.0"

1	compile "com.google.android.gms:play-services-gcm:8.4.0"

compile 'com.google.firebase:firebase-messaging:9.0.2'

1	compile 'com.google.firebase:firebase-messaging:9.0.2'

And now all the major changes just replace the code in manifest from

<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" />

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

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

        <service
            android:name=".MyGcmListenerService"
            android:exported="false" >
            <intent-filter>
                <action android:name="com.google.android.c2dm.intent.RECEIVE" />
            </intent-filter>
        </service>
        <service
            android:name=".RegistrationIntentService"
            android:exported="false" >
            <intent-filter>
                <action android:name="com.google.android.c2dm.intent.REGISTRATION" />
                <action android:name="com.google.android.c2dm.intent.RECEIVE" />
            </intent-filter>
        </service>
        <service
            android:name=".MyInstanceIDListenerService"
            android:exported="false" >
            <intent-filter>
                <action android:name="com.google.android.gms.iid.InstanceID" />
            </intent-filter>
        </service>

<receiver

android:name="com.google.android.gms.gcm.GcmReceiver"

android:exported="true"

android:permission="com.google.android.c2dm.permission.SEND" >

<intent-filter>

</intent-filter>

</receiver>

<service

android:name=".MyGcmListenerService"

android:exported="false" >

<intent-filter>

</intent-filter>

</service>

<service

android:name=".RegistrationIntentService"

android:exported="false" >

<intent-filter>

</intent-filter>

</service>

<service

android:name=".MyInstanceIDListenerService"

android:exported="false" >

<intent-filter>

</intent-filter>

</service>

to the new code

<service
            android:name=".MyFcmListenerService"
            android:exported="false" >
            <intent-filter>
                <action android:name="com.google.firebase.MESSAGING_EVENT" />
            </intent-filter>
        </service>
        <service
            android:name=".MyInstanceIDListenerService"
            android:exported="false" >
            <intent-filter>
                <action android:name="com.google.firebase.INSTANCE_ID_EVENT" />
            </intent-filter>
        </service>

<service

android:name=".MyFcmListenerService"

android:exported="false" >

<intent-filter>

</intent-filter>

</service>

<service

android:name=".MyInstanceIDListenerService"

android:exported="false" >

<intent-filter>

</intent-filter>

</service>

The new MyInstanceIDListenerService.java

public class MyInstanceIDListenerService extends FirebaseInstanceIdService {
   
    @Override
    public void onTokenRefresh() {
        String refreshedToken = FirebaseInstanceId.getInstance().getToken();
        SendTokenToServer(refreshedToken); 
    }

    public void SendTokenToServer(String token) {
        //YOUR CODE TO SEND TOKEN TO YOUR SERVER
    }
}

public class MyInstanceIDListenerService extends FirebaseInstanceIdService {

@Override

public void onTokenRefresh() {

String refreshedToken = FirebaseInstanceId.getInstance().getToken();

SendTokenToServer(refreshedToken);

}

public void SendTokenToServer(String token) {

//YOUR CODE TO SEND TOKEN TO YOUR SERVER

}

The FCMListenerService.java

public class MyFcmListenerService extends FirebaseMessagingService {

    @Override
    public void onMessageReceived(RemoteMessage remoteMessage) {
        Map data = remoteMessage.getData();
        String title = data.get("title").toString(); //your key value instead of 'title'
        String message = data.get("message").toString(); //your key value instead of 'de 
        sendNotification(title, message);
    }
 
    public void sendNotification(String head, String Content){
    //code to create a notification
    }
}

public class MyFcmListenerService extends FirebaseMessagingService {

@Override

public void onMessageReceived(RemoteMessage remoteMessage) {

Map data = remoteMessage.getData();

String title = data.get("title").toString(); //your key value instead of 'title'

String message = data.get("message").toString(); //your key value instead of 'de

sendNotification(title, message);

}

public void sendNotification(String head, String Content){

//code to create a notification

}

An you are ready to go. All the setup is ready just a little bit change, on the Activity in which you want to create the FCM token in your application just add the code

sendTokenServer(FirebaseInstanceId.getInstance().getToken());

1	sendTokenServer(FirebaseInstanceId.getInstance().getToken());

and the function sendTokenToServer(). And FCM is implemented but don’t forgot that now the API-Key and Sender Key is changed so update them on the server side.

You can also test the application notification from Firebase console as you can directly send message from there. For any assistance you can visit the link.

Aastha 15 December 2016

. . .

8 comments

Anmol Arora Jun 25, 2016 at 10:19 am

I’ve already migrated and the new fcm configuration is working fine. But my concern is that I’m not able to send push notification to the GCM registration tokens. When I try sending the push to old gcm registration token through Firebase Console it fails. Can you give any input on that?

aastha gupta Jul 15, 2016 at 1:56 pm
Hi Anmol, please check your Server API key, I guess it must have changed while migrating to FCM. If its changed then you can’t send messages to those GCM tokens from FCM console.

Reply

aastha gupta Jun 30, 2016 at 12:34 pm

Hi Anmol, you can’t send messages to earlier GCM registered devices through FCM console as the Server_API_key is changed during migration to FCM. And older GCM tokens or topics (in case of topic messaging) are connected to older API_key only.
You can use your former method of sending messages for contacting GCM users and FCM for new ones (but be sure of the API_key you are using) for 2- 3 updates after that most of your users must have been updated the app. Then you can completely move on to FCM console.

diti Sep 27, 2016 at 11:14 am

it has another method for sendin api requests, dont use the old url and request data, see the documentation for server request for Firebase, here is an example on server of FCM-server request with PHP:
https://uploads.disquscdn.com/images/b5115819254f5a3c143b407854a3704f8301919076a55595ed59c1339e5bf560.png

Aastha (Moderator) Sep 27, 2016 at 11:30 am
Yes FCM do have another method but its not strictly required to change the api. You can check it here
Please check the last line.

Reply

Alexander Ustinov Oct 3, 2016 at 10:24 am

It’s cool, but what will be with old apps on GCM?

Will It work correctly?

Aastha (Moderator) Oct 3, 2016 at 10:32 am
They will be fine as mostly the Server key (API key) remains same. So you can send notifications to them as well but not from Firebase console.

Reply
aastha gupta Oct 3, 2016 at 12:22 pm
They will be fine as mostly the Server key (API key) remains same. So you can send notifications to them as well but not from Firebase console.

Reply

Migrating to FCM from GCM

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