Under Settings > Apps > any app, there is a section labeled "Mobile data usage" and another "App battery usage". Inside each of these, there is a toggle "Background data" and "Allow background usage", respectively.
Assuming that we are talking about an app for which we don't care to receive notifications, what purpose does it serve to have these two toggles enabled?
That, and I was also wondering what exactly changes by toggling OFF the "allow background usage"?
Anyone6308
Some apps are designed to do things in the background: music players are the most obvious example that comes to mind, but I'm sure there are others.
If there is no obvious reason for an app to run in the background, you can always try turning those off and see if it breaks anything.
Regarding notifications, if an app uses FCM & Play Services for notifications, the app doesn't even need to run in the background to get them.
Probably9857 music players
That's not a great example, because I guess music players would probably use a foreground process.
In general:
Background process = you can't see it or interact with it
Foreground process = you can at least see it (it will have some kind of status bar notification)
Probably9857 i may have phrased incorrectly the notifications part. What I meant was messaging apps that require fetching new messages to then present them in the notifications. But now that you mentioned that apps don't need to run in the background for notification services, how is it possible? How can an app not be running and yet still display notifications?
Probably9857 I don't know about anything else, but Tidal does need background battery usage.
Which is a bummer, cuz then it keeps pumping juice indefinitely if you forget to close it and leave it on pause, even on Optimized setting.
Anyone6308 How can an app not be running and yet still display notifications?
With FCM push notifications, Play Services is always running in the background. Play Services receives the notification, then either displays it directly in some cases, or delegates it to the app (starting it up if necessary if it's not running).
Not all apps use FCM for notifications though. Many apps just check for notifications on a schedule, or keep a network socket open. These apps would need to be able to run in the background for notifications to work.