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)

Building a pie chart

We know that a pie chart is a way to represent proportional numeric values, using slices that form a circle—a pie.

With a pie chart being made up of a slice and a circle – simple geometric shapes – it is simple enough to implement them in SwiftUI.

This recipe will use a dataset on the number of pets in three different European cities.

Getting ready

This recipe doesn't have any external resources, so it is enough just to create a SwiftUI project called PieChartApp.

How to do it...

This recipe is slightly more complicated than usual because it has two main parts:

  • Manipulating datapoints
  • Visualizing datapoints

Regarding the datapoints, given the list of data, we must scale the value to adapt to the maximum, meaning that we must calculate the maximum value in the series and then scale the other values so that each value can fit the pie chart. Also, we must calculate the angles for each slice – the...