The NSFetchedResultsController class isn't an essential component of a Core Data application, but it makes working with collections of managed objects much easier. This tutorial introduces you to the, almost magical, NSFetchedResultsController class.
An application powered by Core Data needs to make sure the state of the persistent store is reflected by the user interface and vice versa. If a record is deleted from the persistent store, the user interface needs to be updated, informing the user about this event.
The boilerplate code required to update a table view is pretty lengthy. For every table view that manages a list of records, you need to write the same boilerplate code. By using the NSFetchedResultsController� class, you only need to write code that is specific to your application. Trivial tasks, such as updating a table view cell when a record is modified, are handled by the fetched results controller.
A fetched results controller manages the results of a fetch request. It notifies its delegate about any changes that affect the results of that fetch request. It even offers the ability to use an in-memory cache to improve performance.
Even though the NSFetchedResultsController class was designed with table views in mind, it also works great with collection views. In this tutorial, we build a basic notes application that keeps track of your notes. We first need to create a project, set up the Core Data stack, and design the data model.
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