Returns from the Background
idle Refresh Event
In some situations you might want the app to run Actions when it returns from the background. An example is if you have a list with news the feed might be old when call the app from the background and you'll want to refresh the data source to pull in the updated feed with the latest news.
To control what Actions happen when the app returns from the background got to "Edit App".
Go the "Events" tab.
Scroll down to "Idle Refresh". Here you can set an Action or series of Actions that will run when the app returns to the foreground.
See Also: How to you get your app to run in the background