Book Image

Mastering iOS 12 Programming - Third Edition

By : Donny Wals
Book Image

Mastering iOS 12 Programming - Third Edition

By: Donny Wals

Overview of this book

The iOS development environment has significantly matured, and with Apple users spending more money in the App Store, there are plenty of development opportunities for professional iOS developers. However, the journey to mastering iOS development and the new features of iOS 12 is not straightforward. This book will help you make that transition smoothly and easily. With the help of Swift 4.2, you’ll not only learn how to program for iOS 12, but also how to write efficient, readable, and maintainable Swift code that maintains industry best practices. Mastering iOS 12 Programming will help you build real-world applications and reflect the real-world development flow. You will also find a mix of thorough background information and practical examples, teaching you how to start implementing your newly gained knowledge. By the end of this book, you will have got to grips with building iOS applications that harness advanced techniques and make best use of the latest and greatest features available in iOS 12.
Table of Contents (35 chapters)
Title Page
Copyright and Credits
Packt Upsell

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...