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Mastering iOS 12 Programming

You're reading from   Mastering iOS 12 Programming Build professional-grade iOS applications with Swift and Xcode 10

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Product type Paperback
Published in Oct 2018
Publisher Packt
ISBN-13 9781789133202
Length 750 pages
Edition 3rd Edition
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Author (1):
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Donny Wals Donny Wals
Author Profile Icon Donny Wals
Donny Wals
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Table of Contents (29) Chapters Close

Preface 1. UITableView Touch-up 2. A Better Layout with UICollectionView FREE CHAPTER 3. Creating a Detail Page 4. Immersing Your Users with Animation 5. Understanding the Swift Type System 6. Writing Flexible Code with Protocols and Generics 7. Improving the Application Structure 8. Adding Core Data to Your App 9. Fetching and Displaying Data from the Network 10. Being Proactive with Background Fetch 11. Syncing Data with CloudKit 12. Using Augmented Reality 13. Improving Apps With Location Services 14. Making Smarter Apps with CoreML 15. Tracking Activity Using HealthKit 16. Streamlining Experiences with Siri 17. Using Media in Your App 18. Implementing Rich Notifications 19. Instant Information with a Today Extension 20. Exchanging Data With Drag And Drop 21. Improved Discoverability with Spotlight and Universal Links 22. Extending iMessage 23. Ensuring App Quality with Tests 24. Discovering Bottlenecks with Instruments 25. Offloading Tasks with Operations and GCD 26. Submitting Your App to the App Store 27. Answers 28. Other Books You May Enjoy

Reading and writing data in a Core Data database


The first step to implement data persistence for your app is to make sure that you can store data in the database. You have defined the models that you want to store in your database so the next step is to actually store your models. Once you have implemented a rough version of your data persistence, you will refine the code to make it more reusable. The final step will be to read data from Core Data and dynamically respond to changes in the database.

Understanding data persistence

Whenever you want to persist a model with Core Data, you must insert a new NSManagedObject into an NSManagedObjectContext. Doing this does not immediately persist the model. It merely stages the object for persistence in the current NSManagedObjectContext. If you don't properly manage your managed objects and contexts, this is a potential source of bugs. For example, not persisting your managed objects results in the loss of your data once you refresh the context...

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