Data Storage Recipes
When working in iOS, one of the most important concepts to understand is the implementation of persistence. This means having information saved and retrieved, or persisted, through the closing or restarting of an application. Just as pages from books can be read and re-read, even after closing and re-opening them, you can make use of certain key concepts in iOS to allow your information—from the simplest values to the most complex data structures—to stay stored in your device for indefinite periods of time.
In this chapter, we cover many data persistence methods that will allow you to save data for offline use including user defaults, documents, databases, and even iCloud. We will show you the different advantages ...