I have recently been cleaning up my phone, reconfiguring apps etc and I found out there are a few third party apps that I can not - ever - disable from running in the background. They will always run.
Now, if I ever need to make one of my applications always run in the background, how would I do it on WP8.1? The third party applications seem somehow to be able to do it but I cannot find any reference to some permanent background process code which cannot be disabled?
I noticed the apps which run in the background cannot be disabled because they are listed as normal apps, not as apps which run in the background.
Here are some screenshots:
Kik Messenger and Messenger third party apps
Kik Messenger and Messenger in the Battery Saver dialog showing usage statistics, compare it to a non-background app named Games from Microsoft.
Here is the Battery Saver list of apps that *can run* in the background:
As is noticable - both of the apps are not there. What kind of magic coding has been used? Both apps seem to function in the background.
I haven't confirmed this but my guess would be that those 2 apps are using VoipHttpIncomingCallTask agent and not using the other Voip tasks listed in http://msdn.microsoft.com/en-us/library/windows/apps/microsoft.phone.networking.voip(v=vs.105).aspx. If you have the time perhaps you can create a simple app in this manner to confirm this.
VoipHttpIncomingCallTask is invoked when the app receives a push notification for an "incoming call" (which would be sent by your app's cloud server for example). These apps are likely using this task to indicate a incoming chat has occurred (ex: by raising a toast for the incoming chat) instead of starting an incoming voip call (which would have invoked the incoming call UI).
Whether the Battery Saver app not showing these apps due to this reason is intentional or not is not clear to me. If it is indeed the reason I wouldn't assume this behavior would remain always as the Battery Saver app could be updated to treat these apps differently in the future.
