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
Dedication
Packt Upsell
Contributors
Preface
Index

Adding Core Data to an existing application


When you create a new project in Xcode, Xcode asks whether you want to add Core Data to your application. If you check this checkbox, Xcode will automatically generate some boilerplate code that sets up the Core Data stack. For practicing purposes, MustC was set up without Core Data so you'll have to add this to the project yourself. Start by opening AppDelegate.swift and add the following import statement:

import CoreData 

Next, add the following lazy variable to the implementation of AppDelegate:

private lazy var persistentContainer: NSPersistentContainer = {
      let container = NSPersistentContainer(name: "MustC")
      container.loadPersistentStores(completionHandler: { (storeDescription, error) in
        if let error = error {
          fatalError("Unresolved error (error), (error.userInfo)")
        }
      })
      return container
  }()

Note

If you declare a variable as lazy, it won't be initialized until it is accessed. This is particularly...