In a previous tutorial I presented a specific new multitasking feature in iOS 7, the Background Fetch, showing how easy it is to make an app to schedule downloads in the background. In this tutorial, I am going to work with another great multitasking feature, named Background Transfer Service.
Prior to iOS 7, only a few kinds of application were allowed to download resources or content on the background while they would not run, and just for a limited time. Big downloads should actually occur while the app was in the foreground, and that was a hard fact for all developers. However, things changed in iOS 7 with the Background Transfer Service coming, as it totally eliminates all the limitations presented above. Not only every app can download content while it’s not running, but it can also have as much time as it’s required at its disposal until all downloads are over.
Great flexibility and more power comes when the Background Transfer Service is combined with other multitasking features, such as the Background Fetch. For example, using the Background Fetch an app can schedule and initiate a download in the limited time that has at its disposal, and then using the Background Transfer Service to perform the actual data downloading.