Service started from widget doesn't work in Oreo

Question

When I implemented my widget a couple years ago, I used this advice from the App Widgets page on the development site (still there): "If your App Widget setup process can take several seconds (perhaps while performing web requests) and you require that your process continues, consider starting a Service in the onUpdate() method." I did this and it worked like a charm when built for SDKs up through 25.

It also worked on Android 8.0, but as soon as I targeted 26, the app started crashing in the onUpdate method of the widget provider when issuing the startService call. The error message had to do with trying to start a background service from another background service, and although I tried a few things in the service definition in the manifest I couldn't get it working.

I ended up doing a workaround when I decided that I didn't really need to update the widget from a service, so now just do the update directly in onUpdate. Services and background/foreground issues are something I've not messed with much, but I'd still like to know if there is a way to have kept using a service to update the widget.

Answer 1

in Android O, we have a new background limitations. When you're trying to startService(), you will get IlleagalStateException, so now you should use startForegroundService(), but if you start service by this new method, you will get RemoteServiceException. To avoid this exception you have 5 seconds to make startForeground() after startForegroundService(), to notify user, that you're working in background.

So, where is only one way in Android O:

context.startForegroundService(intent)

And in service onCreate() make something like that:

startForeground(1, new Notification());

UPDATE So as i assume, some manufacturers have backport on Android N these new background limitations, that's why you can get same exception in Android N.

Answer 2

Without a Minimal, Complete, and Verifiable example, it is difficult to help you. Depending on what you had, you could have:

• Switched to JobIntentService, particularly if your old service was an IntentService and you did not mind the possibility of a several-second delay in the work being started

• Called startForegroundService() on Context (instead of startService()) to start your service, and in your service call startForeground(), to make your service be a foreground service

• Called getForegroundService() on PendingIntent (instead of getService()), and in your service call startForeground(), to make your service be a foreground service