[Xamarin.Firebase.Messaging] Cannot receive push notifications when app is closed

[Alexander-Alekseev]

Xamarin.Android Version (eg: 6.0):

Xamarin.Forms v4.3.0.908675 (not the latest one, but the "previous" one)
Xamarin.Android.* libs are v28.0.0.3

Operating System & Version (eg: Mac OSX 10.11):

Edition: Windows 10 Pro
Version: 1809
OS Build: 17763.805

Google Play Services Version (eg: 8.4.0):

Xamarin.GooglePlayServices.Base v71.1610.0
Xamarin.Firebase.Messaging v71.1740.0

Describe your Issue:

Title says the problem.
Application receives push notification in both foreground and background, but does not receive them if I force close it.
I followed both Xamarin and Firebase/Google tutorials to 'integrate' Firebase messaging services.
I do have google-services.json in my project (in the Android project, not in the common one).
OnMessageReceived is not called when app is closed (I checked logs).
I payload only data messages, not notification messages.
I'm sure that server side works correctly, because my Java Android application with the same settings (and the same google-services.json) is able to receive push notifications when it's closed.
What else can be checked? Please let me know.

Steps to Reproduce (with link to sample solution if possible):

Implementation of FirebaseMessagingService: https://gist.github.com/Alexander-Alekseev/cb555f0ee5bb56c33229e3fbb1848682.
Android manifest: https://gist.github.com/Alexander-Alekseev/d4a0a603afd6ff7b7038b7f854f1e4d7.

Include any relevant Exception Stack traces, build logs, adb logs:

[CanT94]

I have the same problem. Since 1 week the Android Push Notifications stopped working, when I close the app. The store version of my app doesnt have this problem, so it has to be something that came from an update. I am testing it right now and it works if I have the app open and press on home button then it still works, but as soon as I close the app it stops receiving notifications.

[Alexander-Alekseev]

@CanT94, hey, could you please share which versions of Xamarin.Forms, Xamarin.GooglePlayServices.Base, Xamarin.Firebase.Messaging etc. did you use in your build which was uploaded to store and receives push notifications?

[Alexander-Alekseev]

Hi @moljac, no news here? Do you need any additional info?

@CanT94, hello again, could you please help us to find out which packages versions did you use in your store version?

[moljac]

@Alexander-Alekseev Sorry, but no new info right now. I need to sit down and dig into docs. Seems it might be different behavior for closed and force closed apps, but not 100% sure

[moljac]

Yes package version diff/comparisnon would help.

[Loki606]

v71 of all relevant Firebase packages and none of the tutorials are working.

[Alexander-Alekseev]

Hey @moljac, still no news here?
Last time you mentioned 'docs' which you need to dig into. Could you please share which docs did you mean? Maybe I can find something helpful that can increase the speed of solving the problem...

[MattVon]

I made a post on StackOverflow with little success right now, I created a sample project to work on isolating this issue but my sample project works spot on (Foreground, Background and app killed)... Although I've ensured nuget packages, code, manifests, etc. are identical from my sample project to my main project - yet my main project experiences this same issue regardless.

[FrankSzendzielarz]

Likewise same issue. Had 4.3 Forms, just updated to latest today and still same problem.

[Alexander-Alekseev]

@MattVon,
@FrankSzendzielarz,
hi, I got a new email from MS/Xamarin support team yesterday. Here it is:

This is indeed a confirmed bug within the framework and it seems that a few users are experiencing a similar issue as well.

The product team that works on the GooglePlayComponents for Xamarin are aware of this issue and are working towards a resolution. We’ve brought the Github issue that you’ve posted to their attention and we can follow the status of the report via the following link: #273

This is likely due to the new libraries (AndroidX) that are being released as the product has been focusing on making these available as quickly as they can. The issue might be resolved once these libraries have become a stable release and available via NuGet.

I am going to archive this case temporarily while we wait for this bug to be fixed, I will certainly reach out to you should there be any updates that resolves this issue.

Since the support team refers to this task, let's continue the discussion here.

[FrankSzendzielarz]

OK, I finally got this working. Still seem to be some minor issues in my project, probably to do with token refresh, but the core issue of notifications not being received when app is closed now seems to be resolved for me. There were a number of confusing factors.

1. Main issue turned out to be accessing shared library App property setters from the constructor of the derived FirebaseMessagingService. I had to work around this.
2. Issue 1) was largely down to my lack of understanding of Android architecture coming at this as a Xamarin .NET developer. I learnt that an Android 'app' consists of at least 3 components (following is my understanding, caveat emptor): the App UI, Services and Receivers. The app has some different states, such as foreground, stopped, and force stopped. When an app is just stopped by swiping it out of the recents list, only the App UI components is terminated; the services/receivers continue as long as memory is available. When an 'intent' (seems to be android parlance for 'message' or 'event') is received when the app is in the 'swipe stopped' state the receiver/service wakes up and handles it, in my case the Firebase message service/receiver, but the app does not exist. 'Force stopped' kills the app and its services, so it can't work.
3. Running from Visual Studio debugger and then stopping causes a Force Stop. You need to run the app direct on the device a second time after debugging.
4. Most of the online docs for configuring Xamarin are out of date. The Receiver elements in the android manifest are unnessary for example.
5. Getting the logs means running the app on device without debugger, then using Visual Studio Device Log to view the messages.
6. The error message is cryptic "Could not activate JNI Handle 0x7fdbfee170 (key_handle 0x7d963d4) of Java type 'crc64925d64ef8a16450b/FirebaseService' as managed type 'CMSApp.Droid.FirebaseService'."

Suspect that xam/firebase updates modified the lifecycle resulting in the above main issue. Perhaps the updates coincided with code changes that led to this issue.