SwiftUI Migrator Project Setup

Overview

Use this skill at the start of a migration to prepare the app shell for SwiftUI without beginning screen conversion yet.

Core principle: establish a stable SwiftUI entry point first, then migrate startup work and screens on top of it.

When to Use

• The project does not yet have a SwiftUI App entry point
• Tuist deployment targets still need SwiftUI-compatible updates
• SplashScreen.swift and the app shell are missing
• AppDelegate still owns launch-time window setup
• The launch screen and initial SwiftUI splash handoff are not yet aligned

Scope

• Update Tuist deployment targets for SwiftUI support
• Create App.swift
• Create an empty SplashScreen.swift
• Move app entry ownership away from AppDelegate
• Apply file-organization rules for migrated screens and reusable views
• Match the launch screen visually to avoid a startup jump

File Organization Rules

• Screens: Full-screen SwiftUI replacements for UIViewController classes belong in Projects/App/Sources/Screens/.
• Views: Smaller reusable SwiftUI components belong in Projects/App/Sources/Views/.
• Naming: Do not use generic names like ContentView.swift. Use descriptive names such as MainScreen.swift and SplashScreen.swift.

Migration Tasks

1. Update Tuist for SwiftUI

1. Locate all Project.swift files under the Projects/ directory.
2. In each file, find the deploymentTarget.
3. Update every module to at least iOS 18.0.
4. Run tuist generate --no-open.

2. Add the SwiftUI app shell

1. Create Projects/App/Sources/App.swift with a WindowGroup that shows SplashScreen.
2. Create Projects/App/Sources/Screens/SplashScreen.swift.
3. In AppDelegate.swift, remove @UIApplicationMain or @main and remove direct self.window ownership.
4. Keep AppDelegate.swift itself. Do not delete it during setup.

3. Make the splash transition seamless

1. Inspect the launch screen configuration in Info.plist or LaunchScreen.storyboard.
2. Match the same background color and image in SplashScreen.swift.
3. Keep image size and positioning aligned with the launch screen.

Shared References

• Samples: ../swiftuimigrator/guides/samples/step2-app-splash/
• Verification: ../swiftuimigrator/guides/verification-checklists.md
• Troubleshooting: ../swiftuimigrator/guides/troubleshooting.md

Verification

• Run tuist generate --no-open
• Run tuist build
• Confirm there is no duplicate @main or UIApplicationMain conflict
• Confirm the app launches through the SwiftUI shell
• Confirm there is no visible jump between the system launch screen and SplashScreen

Exit Criteria

The project is ready for:

• swiftuimigrator-data-migration if startup logic still needs to move out of UIKit
• swiftuimigrator-screens if the app shell is already stable enough to start screen migration