ios-app-lifecycle

name	ios-app-lifecycle
description	Standards for AppDelegate, SceneDelegate, Deep Linking, and Background Tasks. Use when managing iOS app lifecycle, deep linking, or background task scheduling. (triggers: AppDelegate.swift, SceneDelegate.swift, didFinishLaunchingWithOptions, willConnectTo, backgroundTask, Shortcut, UserActivity)

iOS App Lifecycle Standards

Priority: P0

Implementation Guidelines

App & Scene Delegate

• SceneDelegate: Use for UI windows and scene-specific state in iOS 13+.
• AppDelegate: Focus on app-wide setup (DI, Analytics, Push notification registration).
• Slim Delegates: Move initialization logic to dedicated Bootstrapper or AppCoordinator.

Deep Linking

• Universal Links: Prefer over custom URL schemes. Handle via scene(_:continue:userActivity:).
• Handling logic: Routing should be handled by the Root Coordinator to navigate to specific screens.

Background Tasks

• Background Fetch: Use BGTaskScheduler for periodically refreshing data.
• Expiration: Handle expirationHandler to avoid app kill by the system.

Anti-Patterns

• No complex logic in didFinishLaunching: Use a Bootstrapper service.
• No UIWindow setup in AppDelegate: Use SceneDelegate for iOS 13+.
• No synchronous network calls in launch: Move to background thread.

References

• Lifecycle & Background Tasks