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)

Separating presentation from content with ViewBuilder

ViewBuilder is a custom parameter attribute that constructs views from closures. ViewBuilder can be used to create custom views that can be used across the application with minimal or no code duplication. We will create a SwiftUI view, BlueCircle.swift, for declaring the ViewBuilder and implement the custom ViewBuilder. The ContentView.swift file will be used to implement the custom view.

Getting ready

Create a new SwiftUI project named ViewBuildersApp.

How to do it…

  1. Open the ViewBuildersApp and add a new SwiftUI view to the project from the menu: File | New | File.
  2. Select the SwiftUI view from the menu.
  3. Click Next.
  4. Name the file BlueCircle and click Create.
  5. Delete the BlueCircle_Previews: struct from the file (delete all five lines of code).
  6. Add BlueCircle ViewModifier to the file:
    struct BlueCircle<Content: View>: View {
        let content: Content