Book Image

SwiftUI Cookbook

By : Giordano Scalzo, Edgar Nzokwe
Book Image

SwiftUI Cookbook

By: Giordano Scalzo, Edgar Nzokwe

Overview of this book

SwiftUI is an innovative and simple way to build beautiful user interfaces (UIs) for all Apple platforms, right from iOS and macOS through to watchOS and tvOS, using the Swift programming language. In this recipe-based book, you’ll work with SwiftUI and explore a range of essential techniques and concepts that will help you through the development process. The recipes cover the foundations of SwiftUI as well as the new SwiftUI 2.0 features introduced in iOS 14. Other recipes will help you to make some of the new SwiftUI 2.0 components backward-compatible with iOS 13, such as the Map View or the Sign in with Apple View. The cookbook begins by explaining how to use basic SwiftUI components. Then, you’ll learn the core concepts of UI development such as Views, Controls, Lists, and ScrollViews using practical implementation in Swift. By learning drawings, built-in shapes, and adding animations and transitions, you’ll discover how to add useful features to the SwiftUI. When you’re ready, you’ll understand how to integrate SwiftUI with exciting new components in the Apple development ecosystem, such as Combine for managing events and Core Data for managing app data. Finally, you’ll write iOS, macOS, and watchOS apps while sharing the same SwiftUI codebase. By the end of this SwiftUI book, you'll have discovered a range of simple, direct solutions to common problems found in building SwiftUI apps.
Table of Contents (15 chapters)

Chapter 11: Handling Core Data in SwiftUI

Core Data is definitely one of the most essential Apple frameworks in the iOS and macOS ecosystem. Core Data provides persistence, meaning it can save data outside the app's memory, and the data you saved can be retrieved after you restart your app.

Given its importance, it's not a surprise that Apple has implemented some extensions for Core Data to make it work nicely with SwiftUI.

In Core Data language, a stored object is an instance of NSManagedObject, and from iOS 13, NSManagedObject conforms to the ObservableObject protocol so that it can be observed directly by a SwiftUI's view.

Also, NSManagedObjectContext is injected into the environment of the View's hierarchy so that the SwiftUI's View can access it to read and change its managed objects.

A very common feature of Core Data is that you can fetch the objects from the repository. F or this purpose, SwiftUI provides the @FetchRequest property wrapper...