ax-uikit

UIKit

Quick Patterns

UIViewRepresentable (UIView -> SwiftUI)

struct MapView: UIViewRepresentable {
    let region: MKCoordinateRegion

    func makeUIView(context: Context) -> MKMapView {
        let map = MKMapView()
        map.delegate = context.coordinator
        return map
    }

    func updateUIView(_ map: MKMapView, context: Context) {
        // Guard: only update if actually changed
        if map.region.center.latitude != region.center.latitude {
            map.setRegion(region, animated: true)
        }
    }

    static func dismantleUIView(_ map: MKMapView, coordinator: Coordinator) {
        map.removeAnnotations(map.annotations)
    }

    func makeCoordinator() -> Coordinator { Coordinator(self) }

    class Coordinator: NSObject, MKMapViewDelegate {
        var parent: MapView
        init(_ parent: MapView) { self.parent = parent }
    }
}

Lifecycle: makeUIView (once) -> updateUIView (every state change) -> dismantleUIView (cleanup).

Coordinator with Bindings (UIKit -> SwiftUI)

struct SearchField: UIViewRepresentable {
    @Binding var text: String

    func makeUIView(context: Context) -> UISearchBar {
        let bar = UISearchBar()
        bar.delegate = context.coordinator
        return bar
    }

    func updateUIView(_ bar: UISearchBar, context: Context) {
        bar.text = text  // SwiftUI -> UIKit
    }

    func makeCoordinator() -> Coordinator { Coordinator(self) }

    class Coordinator: NSObject, UISearchBarDelegate {
        var parent: SearchField
        init(_ parent: SearchField) { self.parent = parent }

        func searchBar(_ searchBar: UISearchBar, textDidChange searchText: String) {
            parent.text = searchText  // UIKit -> SwiftUI
        }
    }
}

UIViewControllerRepresentable

struct PhotoPicker: UIViewControllerRepresentable {
    @Binding var selectedImages: [UIImage]
    @Environment(\.dismiss) private var dismiss

    func makeUIViewController(context: Context) -> PHPickerViewController {
        var config = PHPickerConfiguration()
        config.selectionLimit = 5
        config.filter = .images
        let picker = PHPickerViewController(configuration: config)
        picker.delegate = context.coordinator
        return picker
    }

    func updateUIViewController(_ picker: PHPickerViewController, context: Context) {}
    func makeCoordinator() -> Coordinator { Coordinator(self) }

    class Coordinator: NSObject, PHPickerViewControllerDelegate {
        var parent: PhotoPicker
        init(_ parent: PhotoPicker) { self.parent = parent }

        func picker(_ picker: PHPickerViewController, didFinishPicking results: [PHPickerResult]) {
            parent.selectedImages = []
            for result in results {
                result.itemProvider.loadObject(ofClass: UIImage.self) { image, _ in
                    if let image = image as? UIImage {
                        DispatchQueue.main.async { self.parent.selectedImages.append(image) }
                    }
                }
            }
            parent.dismiss()
        }
    }
}