SwiftUI Cookbook

A guide to solving the most common problems and learning best practices while building SwiftUI apps, 2nd Edition

Giordano Scalzo, Edgar Nzokwe

• Publisher: Packt Publishing
• Year: 2021
• ISBN:
  9781803240435
• Edition: 2
• Topic: Computer Science
• Subtopic: Programming
• Index: Computer Science

Unleash the power of declarative programming in SwiftUI by building cross-platform Apple apps for iOS 15, macOS, and watchOS using Swift 5.5, Xcode 13, and SwiftUI 3

Key Features

• Apply the declarative programming paradigm to build cross-platform UIs for Apple devices
• Learn to integrate UIkit, Core Data, Firebase, and Sign in with Apple with SwiftUI
• Adopt the new SwiftUI 3.0 features to build visually appealing UIs speedily

Book Description

SwiftUI provides an innovative and simple way to build beautiful user interfaces (UIs) for all Apple platforms, from iOS and macOS through to watchOS and tvOS, using the Swift programming language. In this recipe-based cookbook, you'll cover the foundations of SwiftUI as well as the new SwiftUI 3 features introduced in iOS 15 and explore a range of essential techniques and concepts that will help you through the development process.

The cookbook begins by explaining how to use basic SwiftUI components. Once you've learned the core concepts of UI development, such as Views, Controls, Lists, and ScrollViews, using practical implementations in Swift, you'll advance to adding useful features to SwiftUI using drawings, built-in shapes, animations, and transitions. 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 by 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 encountered when building SwiftUI apps.

What you will learn

• Explore various layout presentations in SwiftUI such as HStack, VStack, LazyHStack, and LazyVGrid
• Create widgets to quickly display relevant content at glance
• Get up to speed with drawings in SwiftUI using built-in shapes, custom paths, and polygons
• Discover modern animation and transition techniques in SwiftUI
• Add user authentication using Firebase and Sign in with Apple
• Manage concurrency with Combine and async/await in SwiftUI
• Solve the most common SwiftUI problems, such as integrating a MapKit map, unit testing, snapshot testing, and previewing layouts

Who this book is for

This book is for mobile developers who want to learn SwiftUI as well as experienced iOS developers transitioning from UIkit to SwiftUI. The book assumes knowledge of the Swift programming language. Knowledge of object-oriented design and data structures will be useful but not necessary. You'll also find this book to be a helpful resource if you're looking for reference material regarding the implementation of various features in SwiftUI.

Chapter 1: Using the Basic SwiftUI Views and Controls

SwiftUI was launched during Apple's Worldwide Developer Conference (WWDC) in June 2019. Since then, its popularity has kept increasing as it has been adopted more into the Apple developer community. Apple also releases updates every year, adding new and exciting capabilities to SwiftUI.

SwiftUI ditches UIKit concepts such as Auto Layout for an easier-to-use declarative programming model. It allows the fast and easy creation of applications that work across Apple platforms (iOS, iPadOS, and macOS).

Are you still wondering whether you should start learning SwiftUI? Here are a few reasons to convince you:

• SwiftUI apps can work alongside UIKit apps: You can slowly convert your app's user interface (UI) to SwiftUI, one screen at a time.
• Industry adoption: SwiftUI adoption among most companies will take time. Getting a head start and learning SwiftUI now improves your future marketability. SwiftUI today is like the early days of Objective-C versus Swift, where most companies still used Objective-C; now, almost everyone has switched to Swift.
• Low learning curve: SwiftUI offers a low learning curve for people who have used declarative programming before. It is also a great way to start learning declarative programming for those with little-to-no experience.
• Live previews increase speed: SwiftUI live previews provide an instant preview of your UI. You can quickly prototype apps and make any changes required by clients. This greatly improves the speed of UI development.

This book is designed to be your SwiftUI reference material. Each project focuses on a single concept so that you can understand each concept thoroughly, and then combine multiple concepts to build amazing applications.

In this chapter, we will learn about views and controls, SwiftUI's visual building blocks for app interfaces. The following recipes will be covered:

• Laying out components
• Dealing with text
• Using images
• Adding buttons and navigating with them
• Beyond buttons – using advanced pickers
• Applying groups of styles using ViewModifier
• Separating presentation from content with ViewBuilder
• Simple graphics using San Francisco Symbols (SF Symbols)
• Integrating UIKit into SwiftUI—the best of both worlds
• Adding SwiftUI to an existing app
• Exploring more views and controls (iOS 14+)

Technical requirements

The code in this chapter is based on Xcode 13.0. You can download and install Xcode from the App Store.

All the code examples for this chapter can be found on GitHub at https://github.com/PacktPublishing/SwiftUI-Cookbook-2nd-Edition/tree/main/Chapter01-Using-the-basic-SwiftUI-Views-and-Controls.

Laying out components

SwiftUI uses three basic layout components, VStack, HStack, and ZStack. Use the VStack view to arrange components in a vertical axis, HStack to arrange components in a ...