Android - Don't display system notification if not needed

[roccozanni]

Hi,
here at Spreaker we use GCM to notify our mobile apps that they need to sync new data, so we basically send a notification to tell the app that some kind of data are changed and they need to be synced.

We started with Android and now we're working on porting the same features on iOS, but in order to have GCM deliver the notification to the app while is in background we needed to add the content_available parameter. No issue on iOS side but the Android app started behave differently that before.

We target play services 8.4 and we discovered that this version introduced the auto-display of the system notification in content_available is specified. The issue here is that there isn't anything to display because we intentionally don't fill the notification field, but the system displays an "empty" notification with just the app icon and the name of the app. We discovered that this behaviour is implemented in GcmListenerService that checks if the value of gcm.notification.e is 1 but providing fallbacks value for all the values of the notification field if not specified.

The gcm.notification.e field seems to be automatically added to the notification by GCM when content_available is true, but we have been able to override it by adding the notification field with a value of {"e":0}.

This is clearly an undocumented feature, and we think it will be safer if will be fixed in the GCM server (using gcm.notification.e=0) or in GcmListenerService client by checking if the user don't specify anything in the notification field.

Thanks,
Rocco

[ogeidix]

Hi Rocco,

I am investigating the issue you reported.
Will update the thread soon.

thanks for your report

• Diego

[macecchi]

I've also encountered the exact same problem as you. I took a while to realise this was a bug... I did not find a solution that covered all the cases, and eventually I gave up background notifications on iOS when the app is closed. This issue should be top priority as this is a big problem when implementing support for the two platforms at the same time.

[ogeidix]

The fix has been completed server-side, and should be deployed in production next week.

[atrepeklis]

I am still getting the issue is it still not deployed or ...?

[ogeidix]

Not yet. It will happen in the next days

[bearprada]

hi @ogeidix did you deploy this fix yet?

[ogeidix]

yes, the issue has been fixed.
Are you still experiencing this?

[bearprada]

@ogeidix I'm not sure it's related to this PR, I used FCM SDK(9.0.0) in client site, and our server sent the notification through GCM. I need to do more test on it. I will keep you posted.