Book Image

SwiftUI Cookbook - Second Edition

By : Giordano Scalzo, Edgar Nzokwe
Book Image

SwiftUI Cookbook - Second Edition

By: Giordano Scalzo, Edgar Nzokwe

Overview of this book

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.
Table of Contents (17 chapters)

Previewing a layout in dark mode

SwiftUI has built-in functionality to support dark mode. With Xcode previews, you can preview your views from light to dark mode with minimal effort by just changing the Xcode previews color scheme environment value.

In this recipe, we will add a dark mode to a minimalistic app with just a single Text view.

Getting ready

Create a new SwiftUI app named DarkModePreview.

How to do it

Since the inception of SwiftUI, there has been an issue with previews, where you cannot preview any view in dark mode except when the view is wrapped in a NavigationView. Is this a feature or a bug? Hopefully, we get the answer in the next releases of SwiftUI.

In this recipe, we'll enclose a Text view in a NavigationView and preview it in light and dark mode. The steps are as follows:

  1. Open the ContentView.swift file.
  2. Above the body variable, add an @Environment variable that checks for the current color scheme:
    @Environment(\.colorScheme...