Hi @ErnSur,
Thanks for the question. This is the expected behavior outlined in the docs here,
https://firebase.google.com/docs/cloud-messaging/android/receive

There is some more discussion on this in this post,
https://stackoverflow.com/questions/37358462/firebase-onmessagereceived-not-called-when-app-in-background

Hope this helps.

Hi @vimanyu,
I see that you linked some references to Android side of the API and while I understand some technical limitations that may cause this behavior this still does not resolve my problem.

1. As described in my issue, behavior is different between SDK versions.
2. Android section of the documentation that you provided tells me to use Android intent - API that is not available from Unity's C# API.
3. Unity section of the documentation does not mention any of discussed problems.

Hi @ErnSur,
I apologize I missed the part where you mentioned that it behaves differently on 6.15.1.
I tried it with the messaging unity quickstart testapp and it is indeed different but I dont see any information about the notification being passed to that event.

    public virtual void OnMessageReceived(object sender, Firebase.Messaging.MessageReceivedEventArgs e) {
}      DebugLog("Received a new message");
      var notification = e.Message.Notification;
      if (notification != null) {
        DebugLog("title: " + notification.Title);
        DebugLog("body: " + notification.Body);
        var android = notification.Android;
        if (android != null) {
            DebugLog("android channel_id: " + android.ChannelId);
        }
      

6.16.1/6.15.1 foreground, I can see all the information from the notification.
6.16.1 background, onMessageReceived isn't called at all
6.15.1 background, onMessageReceived seems to be called but notification has no information.

Are you observing something similar on 6.15.1?

I will get in touch with the team to figure out what the expected behavior is here.

I experienced the same behavior, from what I can remember the title and body was missing but not the FirebaseMessage.Data.

Hi @ErnSur,
Thanks for flagging this. We found the problem and it was because we updated our messaging service to use JobIntentService instead of IntentService (recommended way introduced in Android O). I have queued the fix up for the next release but dont have an estimate of when that will be going out yet.

If you are curious, the change that caused the difference in behavior from 6.15.1 to 6.16.+.
https://github.com/firebase/firebase-cpp-sdk/pull/152/files#diff-7c5c8af611cc405196971b004848f71aef21053d9ebf196914548e488641c639
Look for changes in the file MessageForwardingService.java.

onHandleWork and consequently onHandleIntent was not being called after we moved to using JobIntentService. This meant that "data payloads" from notification didn't make it to the queue.

If you absolutely need the latest and dont mind building from our source, let me know and I can provide you a workaround before our next release.

Hi @ErnSur,
Thanks for flagging this. We found the problem and it was because we updated our messaging service to use JobIntentService instead of IntentService (recommended way introduced in Android O). I have queued the fix up for the next release but dont have an estimate of when that will be going out yet.

If you are curious, the change that caused the difference in behavior from 6.15.1 to 6.16.+.
https://github.com/firebase/firebase-cpp-sdk/pull/152/files#diff-7c5c8af611cc405196971b004848f71aef21053d9ebf196914548e488641c639
Look for changes in the file MessageForwardingService.java.

onHandleWork and consequently onHandleIntent was not being called after we moved to using JobIntentService. This meant that "data payloads" from notification didn't make it to the queue.

If you absolutely need the latest and dont mind building from our source, let me know and I can provide you a workaround before our next release.

I'd like some info on that possible workaround, because our app relies heavily on notifications when app is in the background.

Hi @npicouet,
I apologize but the workaround is more tricky than I expected.
My workaround works for C++ SDK if you are building that from source but you won't be able to build the corresponding Unity SDK as we don't have the open source instructions for that yet. Unfortunately, you will have to wait until the next release. This fix is pending review and should make it into our codebase internally and then we will push out a release with this fix. Until then, you might have to work with the older version. Sorry about that.

I experience the same problem on Unity 2020.1.17f1. Tried all Firebase Cloud Messaging starting from 6.15.x ending with 7.0.2 - everywhere the same result.
Our API form the message like this:

    notification = {
    	to: registration_token,
    	data: {
    		extra: payload['data']
    	}
    }

    if payload['title']
    notification[: notification] = {}
    notification[: notification][: title] = payload['title']
    notification[: notification][: body] = payload['body']
    notification[: notification][: sound] = 'default'
    notification[: notification][: badge] = payload['badge_count'] || '1'

What means it follows the requirement in documentation, because it has data and notification json objects.
The issue 100% reproducable on quickstart project following the instructions of @ErnSur

@vimanyu any way to make it work finally?

Are you seeing the problem in 6.15.1?
The issue that I was looking into is the one that was originally reported in this thread, specifically the difference in behavior between 6.15 and 6.16.+.
As far as that difference in behavior is concerned, I can provide a way to fix it in C++ open source SDK but that won't fix the issue in Unity SDK. The fix is ready in our internal systems and will roll out with the next release.

Are you seeing the problem in 6.15.1?

As I said I tested all SDKs starting from 6.15.0. So yes, it exists. Now I am on 7.0.2, and it still here

The fix is ready in our internal systems and will roll out with the next release.

Did I correctly understand, that this issue existed for almost 1 year (or when that 6.15.0 was released) and only next Unity SDK will include the fix?

To be honest, I can't figure out how such important bugs are

1. were generally admitted
2. were not resolved in a timely manner

In my opinion, this functionality is one of the most important - activation push notification with data transfer. Looks like that was important only to me and the creator of this ticket.

@npicouet, this very severe bug was reported 2 months ago and 6 weeks ago you found the problem. We experience it, too. When do you think this fix will be included in an update for Unity? It's really needed!

I've just hit this issue myself.
'Data-only' messages behave just fine but if I combine my data with a Notification, I risk losing my data if the app is backgrounded.
I guess until this is fixed I'll have no option but to send two messages to perform the dual function of alerting my client and sending data to the application, right?
Unity 2020.1.13f1
Firebase Unity SDK 7.0.2

@npicouet, we just released Unity 7.1.0 which should have a fix for the original issue in this ticket.
If you have some time, could you verify if things are working as expected.

Can confirm @RobBrooks words: 7.1.0 "fix"doesn't work.
Unbelievable...

Hi @RobBrooks and @novavision, I am sorry to hear that but just wanted to clarify some thing. The original issue filed by @ErnSur was a change in behavior of a callback function introduced in 6.16.x (it worked in 6.15.2).

"FirebaseMessaging.MessageReceived does not fire when I click on notification and the app is opened from the background. I experience the issue in SDK versions of 6.16.0 and 6.16.1, I see no problem in version 6.15.2"

It might be a different problem from what you are running into, please correct me if I am wrong but 6.15.x does not work for you at all.

If that is the case, we should create a new issue and we will look into that specifically. Are you able to reproduce the problem in any of the quickstart examples? That will speed up the debugging too.

@vimanyu I am having exactly this case.
Here is the issue I created before finding this one: #883

Everything is pretty clear - clicking the received Push Notification and opening the app (fresh start or from background) MessageReceived not called, and there is no way to get the data from playload.

Hi everyone,
Apologies for the late response. I had some time to look into this and I think I know what is going on. The underlying problem was in our C++ SDK which was fixed in the latest release but Unity SDK has its own Native Custom Activity which is still using the old way of doing things.

I tested the following workaround on my end and now the functionality seems to match what happens in 6.15.1. It will be really helpful if we can get a confirmation this also works on your end.

Tested on Messaging unity quickstart in Unity 2018.4.29f1, Firebase Unity SDK 7.1.0, Android 8.0.
For the workaround, there is a modified Unity Native Activity file and a manifest in the attached zip file
fcm_877.zip

1. Copy FCM_workaround directory from the attached zip file into your Assets directory (this will place the required java code for the modified Unity native activity). Make sure to click on that file in Unity and ensure only "Android" platform is enabled for it in the Inspector panel.

2. Update the block for Messaging in Assets/Plugins/Android/AndroidManifest.xml (there is a file AndroidManifest.xml in the zip file for reference but you might not want to use it as you have other plugins in your project). The important sections to look for are repointing to our modified activity and adding a permission to the messaging service.

# Replace 
    <activity android:name="com.google.firebase.MessagingUnityPlayerActivity" 
# with
    <activity android:name="com.google.firebase_workaround.MessagingUnityPlayerActivityWorkaround" 

AND

# Replace
   <service android:name="com.google.firebase.messaging.MessageForwardingService"  android:exported="false">

# with
    <service android:name="com.google.firebase.messaging.MessageForwardingService"
         android:permission="android.permission.BIND_JOB_SERVICE"
         android:exported="false" >
    </service>

Let me know if there are any questions.