Understanding SwiftUI’s ScenePhase: Managing Your App’s Lifecycle

Introduction

When building apps, it’s essential to understand how your app behaves in different situations. SwiftUI, Apple’s framework for creating user interfaces, introduces a powerful tool for managing your app’s lifecycle: ScenePhase. In this article, we’ll explore what ScenePhase is, why it matters, and how you can use it to create better user experiences in your apps.

When we create a new App in Swift UI, Xcode generates two template files for us:

1. <ProjectName>App file containing a struct that conforms to App protocol and WindowGroup with ContentView(RootView)
2. ContentView, a sample view with just a Text showing “Hello, world!”.

Unlike UIKit Template, where we get App state change methods by default, in SwiftUI we don’t have such methods.

But there is a way to track App State changes:

a. Declare an Environment variable of scene phase.

b. Add an onChange modifier for scenePhase and switch over ScenePhase types to handle states accordingly

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