Learning Core Data for iOS with Swift
Learning Core Data for iOS with Swift has been released! This second edition is written for Apple’s new Swift language.
Groceries is the app you build as you follow the book, which is a shared shopping list using Core Data to cache iCloud data with CloudKit. Download it to multiple iOS devices with different iCloud accounts to test out the data sharing today!
Here’s a brief summary of what you find in each chapter:
Chapter 1, “Your First Core Data Application”—The groundwork is laid as the fundamental concepts of Core Data are introduced. You learn what Core Data is, and just as importantly, what it isn’t. In addition, Core Data integration with an existing application is demonstrated as the CDHelper class is implemented.
Chapter 2, “Managed Object Model Basics”—Data models are introduced as parallels are drawn between traditional database schema design and Core Data. You learn how to configure a basic managed object model as entities and attributes are discussed, along with accompanying advice on choosing the right data types. Inserting, fetching, filtering, sorting, and deleting managed objects are also covered and followed up with an introduction to fetch request templates.
Chapter 3, “Managed Object Model Migration”—Experience lightweight migration, default migration, and using a migration manager to display migration progress. You learn how to make an informed decision when deciding between migration options for your own applications and become comfortable with the model-versioning capabilities of Core Data.
Chapter 4, “Managed Object Model Expansion”—The true power of a relational data model is unlocked as different types of relationships are explained and added to Groceries. Other model features such as abstract and parent entities are also covered, along with techniques for dealing with data validation errors.
Chapter 5, “Table Views”—The application really comes to life as Core Data is used to drive memory-efficient and highly performing table views with a fetched results controller. Of course, most of the generic legwork is put into a reusable table view controller subclass called CDTableViewController. By dropping this class into your own applications, you can easily deploy Core Data–driven table views yourself.
Chapter 6, “Views”—Working with managed objects takes a front seat as you’re shown how to pass them around the application. Objects selected on a table view are passed to a second view, ready for editing. The editing interface is added to Groceries, demonstrating how to work with objects and then save them back to the persistent store.
Chapter 7, “Picker Views”—As a nice touch, Core Data–driven picker views are added to the editing views. Picker views allow the user to quickly assign existing items to a unit of measurement, home location, or shop location. A special reusable text field subclass called CDPickerTextField is introduced, which replaces the keyboard with a Core Data picker view whenever an associated text field is tapped.
Chapter 8, “Preloading Data”—Techniques for generating a persistent store full of default data from XML are explained and demonstrated in this chapter as the generic CDImporter helper class is introduced. Once you have a persistent store to include with a shipping application, you then see how to determine whether a default data import is required or even desired by the user.
Chapter 9, “Deep Copy”—A highly flexible and fine-grained alternative to migratePersistentStore, deep copy enables you to copy objects and relationships from selected entities between persistent stores. In this chapter, the CDImporter helper class is enhanced with the deep copy capability.
Chapter 10, “Performance”—Gain experience with Instruments as you identify and eliminate performance issues caused by the common pitfalls of a Core Data application. The camera functionality is introduced to highlight these issues and demonstrates just how important good model design is to a well-performing application.
Chapter 11, “Background Processing”—Top-notch performance requires intensive tasks be offloaded to a background thread. You learn just how easy it is to run processes in the background as the example of photo thumbnail generation is added with a generic helper class called CDThumbnailer. You also learn how to keep memory usage low with another helper class, called CDFaulter.
Chapter 12, “Search”—This chapter shows you how to integrate a UISearchController with Core Data as you implement efficient search in CDTableViewController.
Chapter 13, “iCloud”—Enjoy the easiest, most reliable Core Data integration with iCloud yet. You learn how to handle multiple accounts and varying preferences on using iCloud without missing a beat.
Chapter 14, “Taming iCloud”—Take iCloud integration to the next level with entity-level seeding and unique object de-duplication. This chapter shows you how to emulate first-time iCloud use by resetting ubiquitous content globally, the right way.
Chapter 15, “CloudKit Sync: Uploading Objects”—This chapter shows you how to leverage a public CloudKit database to keep a small data set synchronized across the devices of a group of iCloud users. Part 1 lays the foundation for synchronization as the capability to automatically upload new NSManagedObjects is added.
Chapter 16, “CloudKit Sync: Downloading Changes and Handling Deletions”—The synchronization implementation is finalized as deletion support and the capability to download changed CloudKit records are added.
Appendix A, “Preparing the Groceries Application”—Every (non–Core Data) step involved in preparing the starting-point application for Chapter 1 is documented here for completeness.
Appendix B, “Finalizing the Groceries Application”—Every (non–Core Data) step involved in finalizing the application for the App Store is documented here for completeness.
Here’s all the source code from the end of each chapter:
You can use all of this code in your own projects, Enjoy!