http://developer.android.com/guide/topics/ui/notifiers/notifications.html on how to create notifications for android. Now my question is: How do I go about listening in the background for updates in the application?
Say I have an app that lets users invite other users to events. I want the invited user to get a notification when this happens. Where would I listen for this in the application? Should I be making a call to the database every few minutes? Is this even possible to do when the application is running in the background?
You will want to create a service in your app. See here specifically for using an IntentService.