swiftui-uikit-interop

What it does

Bridges UIKit and SwiftUI in both directions: wrap UIKit views and controllers, embed SwiftUI in UIKit screens, and synchronize state without duplicating lifecycle ownership.

How it works

• Provides wrappers using UIViewRepresentable and UIViewControllerRepresentable to expose UIKit views and view controllers to SwiftUI.
• Uses a Coordinator class to handle UIKit delegation and callbacks, routing results back to SwiftUI via @Binding or closures.
• Demonstrates embedding SwiftUI content inside UIKit with UIHostingController, including the three-step containment sequence (addChild, add view, didMove).
• Shows how to set up UIHostingConfiguration for cell content in collection/table views and how to manage sizing via sizingOptions and intrinsic content size.
• Explains state synchronization patterns: two-way with @Binding, one-way events with closures, and environment access within representable methods.
• Details UIKit Automatic Observation Tracking considerations and Sendable guidance for coordinators.

When to use it

Use when wrapping UIKit-only or third-party UIKit views/controllers in SwiftUI, embedding SwiftUI in UIKit, integrating mail/share/document/PDF/text-view surfaces, or migrating UIKit apps to SwiftUI incrementally.

What it can touch

• Uses UIViewRepresentable, UIViewControllerRepresentable, UIHostingController, UIHostingConfiguration, and a Coordinator class to bridge between SwiftUI and UIKit.
• Demonstrates interaction with @Binding, closures, and @Observable state tracking.

Caveats

• Advises on proper lifecycle handling (e.g., set delegates in makeUIView/makeUIViewController, guard against update loops).
• Notes platform/version constraints (iOS 16+ sizeThatFits and UIHostingConfiguration; iOS 26+ updateProperties; iOS 18 Info.plist requirement for UIKit tracking; iOS 17 limitations on @Observable).
• Discusses concurrency guidance for coordinators (e.g., @MainActor).