Agent skills for iOS, iPadOS, Swift, SwiftUI, and modern Apple framework development.
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Complete working recipes for common UIKit wrapping scenarios. Each recipe includes the full UIViewRepresentable or UIViewControllerRepresentable struct, the Coordinator with delegate methods, a SwiftUI usage example, and gotchas specific to that wrapper.
Native WebKit for SwiftUI now covers modern embedded web content on iOS 26+. See the
swiftui-webkitskill forWebView,WebPage, navigation policies, JavaScript calls, and migration guidance. Keep this file focused on generic representable patterns.
Display a map with annotations, track region changes, and toggle map type.
import SwiftUI
import MapKit
struct MapViewRepresentable: UIViewRepresentable {
@Binding var region: MKCoordinateRegion
@Binding var mapType: MKMapType
var annotations: [MKPointAnnotation]
var onRegionChanged: ((MKCoordinateRegion) -> Void)?
func makeCoordinator() -> Coordinator { Coordinator(self) }
func makeUIView(context: Context) -> MKMapView {
let mapView = MKMapView()
mapView.delegate = context.coordinator
mapView.showsUserLocation = true
return mapView
}
func updateUIView(_ uiView: MKMapView, context: Context) {
// Update map type
if uiView.mapType != mapType {
uiView.mapType = mapType
}
// Update region -- guard against tiny differences to avoid feedback loops
let currentCenter = uiView.region.center
let threshold = 0.0001
if abs(currentCenter.latitude - region.center.latitude) > threshold ||
abs(currentCenter.longitude - region.center.longitude) > threshold {
uiView.setRegion(region, animated: true)
}
// Diff annotations
let existing = Set(uiView.annotations.compactMap { $0 as? MKPointAnnotation })
let incoming = Set(annotations)
let toRemove = existing.subtracting(incoming)
let toAdd = incoming.subtracting(existing)
uiView.removeAnnotations(Array(toRemove))
uiView.addAnnotations(Array(toAdd))
}
final class Coordinator: NSObject, MKMapViewDelegate {
var parent: MapViewRepresentable
init(_ parent: MapViewRepresentable) { self.parent = parent }
func mapView(_ mapView: MKMapView, regionDidChangeAnimated animated: Bool) {
parent.region = mapView.region
parent.onRegionChanged?(mapView.region)
}
func mapView(
_ mapView: MKMapView,
viewFor annotation: MKAnnotation
) -> MKAnnotationView? {
guard !(annotation is MKUserLocation) else { return nil }
let id = "pin"
let view = mapView.dequeueReusableAnnotationView(withIdentifier: id)
?? MKMarkerAnnotationView(annotation: annotation, reuseIdentifier: id)
view.annotation = annotation
return view
}
}
}struct MapScreen: View {
@State private var region = MKCoordinateRegion(
center: CLLocationCoordinate2D(latitude: 37.7749, longitude: -122.4194),
span: MKCoordinateSpan(latitudeDelta: 0.05, longitudeDelta: 0.05)
)
@State private var mapType: MKMapType = .standard
var body: some View {
MapViewRepresentable(
region: $region,
mapType: $mapType,
annotations: []
)
.ignoresSafeArea()
}
}@Binding region, which triggers updateUIView, which calls setRegion, which triggers the delegate again. The threshold guard is essential.Map view unless you need delegate-level control (custom overlays, clustering, etc.).Wrap UITextView for rich text editing with NSAttributedString binding and placeholder support.
import SwiftUI
struct RichTextEditor: UIViewRepresentable {
@Binding var attributedText: NSAttributedString
var placeholder: String = ""
@Binding var isFirstResponder: Bool
func makeCoordinator() -> Coordinator { Coordinator(self) }
func makeUIView(context: Context) -> UITextView {
let textView = UITextView()
textView.delegate = context.coordinator
textView.font = .preferredFont(forTextStyle: .body)
textView.adjustsFontForContentSizeCategory = true
textView.backgroundColor = .clear
textView.textContainerInset = UIEdgeInsets(top: 8, left: 4, bottom: 8, right: 4)
// Placeholder label
let label = UILabel()
label.text = placeholder
label.font = .preferredFont(forTextStyle: .body)
label.textColor = .placeholderText
label.tag = 999
label.translatesAutoresizingMaskIntoConstraints = false
textView.addSubview(label)
NSLayoutConstraint.activate([
label.topAnchor.constraint(equalTo: textView.topAnchor, constant: 8),
label.leadingAnchor.constraint(equalTo: textView.leadingAnchor, constant: 8),
])
return textView
}
func updateUIView(_ uiView: UITextView, context: Context) {
if uiView.attributedText != attributedText {
uiView.attributedText = attributedText
}
// Update placeholder visibility
if let label = uiView.viewWithTag(999) as? UILabel {
label.isHidden = !uiView.text.isEmpty
}
// First responder management
if isFirstResponder && !uiView.isFirstResponder {
uiView.becomeFirstResponder()
} else if !isFirstResponder && uiView.isFirstResponder {
uiView.resignFirstResponder()
}
}
@available(iOS 16.0, *)
func sizeThatFits(
_ proposal: ProposedViewSize,
uiView: UITextView,
context: Context
) -> CGSize? {
let width = proposal.width ?? UIView.layoutFittingExpandedSize.width
let size = uiView.sizeThatFits(CGSize(width: width, height: .greatestFiniteMagnitude))
return CGSize(width: width, height: max(size.height, 44))
}
final class Coordinator: NSObject, UITextViewDelegate {
var parent: RichTextEditor
init(_ parent: RichTextEditor) { self.parent = parent }
func textViewDidChange(_ textView: UITextView) {
parent.attributedText = textView.attributedText ?? NSAttributedString()
if let label = textView.viewWithTag(999) as? UILabel {
label.isHidden = !textView.text.isEmpty
}
}
func textViewDidBeginEditing(_ textView: UITextView) {
parent.isFirstResponder = true
}
func textViewDidEndEditing(_ textView: UITextView) {
parent.isFirstResponder = false
}
}
}struct NotesEditorView: View {
@State private var text = NSAttributedString()
@State private var isFocused = false
var body: some View {
RichTextEditor(
attributedText: $text,
placeholder: "Write something...",
isFirstResponder: $isFocused
)
.frame(minHeight: 100)
}
}NSAttributedString comparison. The equality check in updateUIView is critical -- without it, every keystroke triggers a full re-render loop.becomeFirstResponder() unconditionally in updateUIView -- it steals focus from other fields.TextEditor in iOS 26 supports AttributedString natively. Prefer it unless you need NSAttributedString or delegate-level control.Display a live camera preview. The preview layer requires a UIView host.
import SwiftUI
import AVFoundation
struct CameraPreview: UIViewRepresentable {
let session: AVCaptureSession
func makeUIView(context: Context) -> CameraPreviewUIView {
let view = CameraPreviewUIView()
view.previewLayer.session = session
view.previewLayer.videoGravity = .resizeAspectFill
return view
}
func updateUIView(_ uiView: CameraPreviewUIView, context: Context) {
// Session is reference type -- no update needed unless swapping sessions
if uiView.previewLayer.session !== session {
uiView.previewLayer.session = session
}
}
}
final class CameraPreviewUIView: UIView {
override class var layerClass: AnyClass { AVCaptureVideoPreviewLayer.self }
var previewLayer: AVCaptureVideoPreviewLayer {
layer as! AVCaptureVideoPreviewLayer
}
override func layoutSubviews() {
super.layoutSubviews()
previewLayer.frame = bounds
}
}struct CameraScreen: View {
@State private var cameraManager = CameraManager()
var body: some View {
CameraPreview(session: cameraManager.session)
.ignoresSafeArea()
.task { await cameraManager.start() }
}
}layerClass. Overriding layerClass avoids adding a sublayer and ensures the preview layer resizes automatically with the view.AVCaptureSession in a separate model. The representable only displays it.previewLayer.connection?.videoRotationAngle if supporting device rotation.Multi-select photo picker that loads selected images asynchronously.
import SwiftUI
import PhotosUI
struct PhotoPicker: UIViewControllerRepresentable {
@Binding var selectedImages: [UIImage]
var selectionLimit: Int = 0 // 0 = unlimited
@Environment(\.dismiss) private var dismiss
func makeCoordinator() -> Coordinator { Coordinator(self) }
func makeUIViewController(context: Context) -> PHPickerViewController {
var config = PHPickerConfiguration(photoLibrary: .shared())
config.filter = .images
config.selectionLimit = selectionLimit
config.preferredAssetRepresentationMode = .current
let picker = PHPickerViewController(configuration: config)
picker.delegate = context.coordinator
return picker
}
func updateUIViewController(_ uiViewController: PHPickerViewController, context: Context) {
// Nothing to update -- configuration is immutable after creation
}
final class Coordinator: NSObject, PHPickerViewControllerDelegate {
let parent: PhotoPicker
init(_ parent: PhotoPicker) { self.parent = parent }
func picker(
_ picker: PHPickerViewController,
didFinishPicking results: [PHPickerResult]
) {
parent.dismiss()
guard !results.isEmpty else { return }
Task { @MainActor in
var images: [UIImage] = []
for result in results {
if let image = await loadImage(from: result.itemProvider) {
images.append(image)
}
}
parent.selectedImages = images
}
}
private func loadImage(from provider: NSItemProvider) async -> UIImage? {
await withCheckedContinuation { continuation in
if provider.canLoadObject(ofClass: UIImage.self) {
provider.loadObject(ofClass: UIImage.self) { image, _ in
continuation.resume(returning: image as? UIImage)
}
} else {
continuation.resume(returning: nil)
}
}
}
}
}struct ImagePickerDemo: View {
@State private var images: [UIImage] = []
@State private var showPicker = false
var body: some View {
VStack {
ScrollView(.horizontal) {
HStack {
ForEach(images.indices, id: \.self) { i in
Image(uiImage: images[i])
.resizable()
.scaledToFill()
.frame(width: 100, height: 100)
.clipShape(.rect(cornerRadius: 8))
}
}
}
Button("Pick Photos") { showPicker = true }
}
.sheet(isPresented: $showPicker) {
PhotoPicker(selectedImages: $images, selectionLimit: 5)
}
}
}picker(_:didFinishPicking:) is called for both selection and cancellation (with empty results). Dismiss in both cases.NSItemProvider.loadObject is completion-based. Wrap in withCheckedContinuation for async/await usage. Load images after dismissal to avoid blocking the picker UI.PhotosUI.PhotosPicker is a native SwiftUI view. Prefer it unless you need custom picker UI or advanced filtering.Present the system email composer with pre-filled fields and handle the result.
import SwiftUI
import MessageUI
struct MailComposer: UIViewControllerRepresentable {
let subject: String
let recipients: [String]
let body: String
var isHTML: Bool = false
var onResult: ((MFMailComposeResult) -> Void)?
@Environment(\.dismiss) private var dismiss
func makeCoordinator() -> Coordinator { Coordinator(self) }
func makeUIViewController(context: Context) -> MFMailComposeViewController {
let controller = MFMailComposeViewController()
controller.mailComposeDelegate = context.coordinator
controller.setSubject(subject)
controller.setToRecipients(recipients)
controller.setMessageBody(body, isHTML: isHTML)
return controller
}
func updateUIViewController(_ uiViewController: MFMailComposeViewController, context: Context) {
// Cannot update mail compose after presentation
}
final class Coordinator: NSObject, MFMailComposeViewControllerDelegate {
let parent: MailComposer
init(_ parent: MailComposer) { self.parent = parent }
func mailComposeController(
_ controller: MFMailComposeViewController,
didFinishWith result: MFMailComposeResult,
error: Error?
) {
parent.onResult?(result)
parent.dismiss()
}
}
}struct FeedbackView: View {
@State private var showMail = false
var body: some View {
Button("Send Feedback") {
guard MFMailComposeViewController.canSendMail() else { return }
showMail = true
}
.sheet(isPresented: $showMail) {
MailComposer(
subject: "App Feedback",
recipients: ["support@example.com"],
body: "I have feedback about..."
) { result in
print("Mail result: \(result.rawValue)")
}
}
}
}canSendMail() before presenting. The app crashes if MFMailComposeViewController is presented on a device with no mail account configured.updateUIViewController is intentionally empty -- the mail compose API does not support changing fields after the controller is shown.MFMailComposeViewControllerDelegate, not MFMailComposeDelegate.Present the system share sheet. This is a UIViewControllerRepresentable because UIActivityViewController is a controller, not a view.
import SwiftUI
struct ShareSheet: UIViewControllerRepresentable {
let items: [Any]
var activities: [UIActivity]? = nil
var excludedTypes: [UIActivity.ActivityType]? = nil
func makeUIViewController(context: Context) -> UIActivityViewController {
let controller = UIActivityViewController(
activityItems: items,
applicationActivities: activities
)
controller.excludedActivityTypes = excludedTypes
return controller
}
func updateUIViewController(_ uiViewController: UIActivityViewController, context: Context) {
// Cannot update after presentation
}
}struct ContentView: View {
@State private var showShare = false
var body: some View {
Button("Share") { showShare = true }
.sheet(isPresented: $showShare) {
ShareSheet(items: ["Check out this app!", URL(string: "https://example.com")!])
.presentationDetents([.medium])
}
}
}.sheet. Do not try to use UIActivityViewController as an inline view -- it is a modal controller.popoverPresentationController. When using on iPad outside of .sheet, set the source view/rect on the popover controller. SwiftUI's .sheet handles this automatically.ShareLink is a native SwiftUI view for Transferable items. Prefer it for simple sharing.Wrap UISearchBar with delegate-based callbacks, debounce support, and cancel button handling.
import SwiftUI
import Combine
struct SearchBar: UIViewRepresentable {
@Binding var text: String
var placeholder: String = "Search"
var onSearch: ((String) -> Void)?
var onCancel: (() -> Void)?
func makeCoordinator() -> Coordinator { Coordinator(self) }
func makeUIView(context: Context) -> UISearchBar {
let searchBar = UISearchBar()
searchBar.delegate = context.coordinator
searchBar.placeholder = placeholder
searchBar.searchBarStyle = .minimal
searchBar.autocapitalizationType = .none
return searchBar
}
func updateUIView(_ uiView: UISearchBar, context: Context) {
if uiView.text != text {
uiView.text = text
}
}
final class Coordinator: NSObject, UISearchBarDelegate {
var parent: SearchBar
private var debounceTask: Task<Void, Never>?
init(_ parent: SearchBar) { self.parent = parent }
func searchBar(_ searchBar: UISearchBar, textDidChange searchText: String) {
parent.text = searchText
searchBar.showsCancelButton = !searchText.isEmpty
// Debounce search
debounceTask?.cancel()
debounceTask = Task { @MainActor in
try? await Task.sleep(for: .milliseconds(300))
guard !Task.isCancelled else { return }
parent.onSearch?(searchText)
}
}
func searchBarSearchButtonClicked(_ searchBar: UISearchBar) {
debounceTask?.cancel()
parent.onSearch?(parent.text)
searchBar.resignFirstResponder()
}
func searchBarCancelButtonClicked(_ searchBar: UISearchBar) {
parent.text = ""
parent.onCancel?()
searchBar.resignFirstResponder()
searchBar.showsCancelButton = false
}
}
}struct SearchableList: View {
@State private var query = ""
@State private var results: [String] = []
var body: some View {
VStack(spacing: 0) {
SearchBar(text: $query, placeholder: "Search items") { text in
results = performSearch(text)
}
List(results, id: \.self) { Text($0) }
}
}
}.searchable modifier. Prefer SwiftUI's .searchable(text:) modifier for standard search patterns. Use this wrapper only when you need precise control over search bar appearance or delegate timing.Task.sleep. Cancel the previous task before starting a new one to debounce. Combine is not needed.showsCancelButton in the delegate, not in updateUIView, to avoid layout jumps.Display PDF documents in SwiftUI using PDFView from PDFKit. Supports loading from URL, Data, or file path, with configurable display mode and auto-scaling.
import SwiftUI
import PDFKit
struct PDFViewer: UIViewRepresentable {
let document: PDFDocument?
var displayMode: PDFDisplayMode = .singlePageContinuous
var autoScales: Bool = true
var displayDirection: PDFDisplayDirection = .vertical
var pageShadowsEnabled: Bool = true
func makeUIView(context: Context) -> PDFView {
let pdfView = PDFView()
pdfView.displayMode = displayMode
pdfView.displayDirection = displayDirection
pdfView.autoScales = autoScales
pdfView.pageShadowsEnabled = pageShadowsEnabled
pdfView.document = document
return pdfView
}
func updateUIView(_ uiView: PDFView, context: Context) {
// Update document if it changed (reference comparison)
if uiView.document !== document {
uiView.document = document
}
if uiView.displayMode != displayMode {
uiView.displayMode = displayMode
}
if uiView.autoScales != autoScales {
uiView.autoScales = autoScales
}
}
}extension PDFViewer {
/// Load a PDF from a URL (local file or remote).
init(url: URL, displayMode: PDFDisplayMode = .singlePageContinuous) {
self.document = PDFDocument(url: url)
self.displayMode = displayMode
}
/// Load a PDF from raw data.
init(data: Data, displayMode: PDFDisplayMode = .singlePageContinuous) {
self.document = PDFDocument(data: data)
self.displayMode = displayMode
}
}struct DocumentView: View {
let pdfURL: URL
var body: some View {
PDFViewer(url: pdfURL)
.ignoresSafeArea(edges: .bottom)
.navigationTitle("Document")
.navigationBarTitleDisplayMode(.inline)
}
}struct RemotePDFView: View {
let url: URL
@State private var document: PDFDocument?
@State private var isLoading = true
@State private var errorMessage: String?
var body: some View {
Group {
if let document {
PDFViewer(document: document)
} else if isLoading {
ProgressView("Loading PDF...")
} else if let errorMessage {
ContentUnavailableView(
"Could Not Load PDF",
systemImage: "doc.text.fill",
description: Text(errorMessage)
)
}
}
.task {
do {
let (data, _) = try await URLSession.shared.data(from: url)
document = PDFDocument(data: data)
} catch {
errorMessage = error.localizedDescription
}
isLoading = false
}
}
}struct NavigablePDFView: UIViewRepresentable {
let document: PDFDocument?
@Binding var currentPageIndex: Int
func makeCoordinator() -> Coordinator { Coordinator(self) }
func makeUIView(context: Context) -> PDFView {
let pdfView = PDFView()
pdfView.displayMode = .singlePageContinuous
pdfView.autoScales = true
pdfView.document = document
NotificationCenter.default.addObserver(
context.coordinator,
selector: #selector(Coordinator.pageChanged(_:)),
name: .PDFViewPageChanged,
object: pdfView
)
return pdfView
}
func updateUIView(_ uiView: PDFView, context: Context) {
if uiView.document !== document {
uiView.document = document
}
// Navigate to page if binding changed externally
if let doc = uiView.document,
let page = doc.page(at: currentPageIndex),
uiView.currentPage != page {
uiView.go(to: page)
}
}
static func dismantleUIView(_ uiView: PDFView, coordinator: Coordinator) {
NotificationCenter.default.removeObserver(coordinator)
}
final class Coordinator: NSObject {
var parent: NavigablePDFView
init(_ parent: NavigablePDFView) { self.parent = parent }
@objc func pageChanged(_ notification: Notification) {
guard let pdfView = notification.object as? PDFView,
let currentPage = pdfView.currentPage,
let document = pdfView.document else { return }
let index = document.index(for: currentPage)
if parent.currentPageIndex != index {
parent.currentPageIndex = index
}
}
}
}PDFView inherits from UIView. Use UIViewRepresentable, not UIViewControllerRepresentable.!== for identity comparison in updateUIView to avoid unnecessary reloads.NotificationCenter with .PDFViewPageChanged -- PDFView does not use a delegate pattern for page changes.dismantleUIView. Failing to remove NotificationCenter observers causes crashes after the view is removed.autoScales fits the PDF to the view width. Disable it if you want the user to start at a specific zoom level.PDFDocument loading can be expensive. Load asynchronously and assign on the main thread.Present the system SMS/MMS composer with pre-filled recipients, body, and optional attachments. Companion to Recipe 6 (MFMailComposeViewController).
import SwiftUI
import MessageUI
struct MessageComposer: UIViewControllerRepresentable {
let recipients: [String]
let body: String
var attachments: [MessageAttachment] = []
var onResult: ((MessageComposeResult) -> Void)?
@Environment(\.dismiss) private var dismiss
func makeCoordinator() -> Coordinator { Coordinator(self) }
func makeUIViewController(context: Context) -> MFMessageComposeViewController {
let controller = MFMessageComposeViewController()
controller.messageComposeDelegate = context.coordinator
controller.recipients = recipients
controller.body = body
for attachment in attachments {
controller.addAttachmentData(
attachment.data,
typeIdentifier: attachment.typeIdentifier,
filename: attachment.filename
)
}
return controller
}
func updateUIViewController(
_ uiViewController: MFMessageComposeViewController,
context: Context
) {
// Cannot update message compose after presentation
}
final class Coordinator: NSObject, MFMessageComposeViewControllerDelegate {
let parent: MessageComposer
init(_ parent: MessageComposer) { self.parent = parent }
func messageComposeViewController(
_ controller: MFMessageComposeViewController,
didFinishWith result: MessageComposeResult
) {
parent.onResult?(result)
parent.dismiss()
}
}
}
struct MessageAttachment {
let data: Data
let typeIdentifier: String // UTI, e.g., "public.jpeg"
let filename: String
}struct InviteView: View {
@State private var showMessage = false
var body: some View {
Button("Send Invite via SMS") {
guard MFMessageComposeViewController.canSendText() else { return }
showMessage = true
}
.sheet(isPresented: $showMessage) {
MessageComposer(
recipients: ["+1234567890"],
body: "Join me on this app!"
) { result in
switch result {
case .sent:
print("Message sent")
case .cancelled:
print("User cancelled")
case .failed:
print("Message failed")
@unknown default:
break
}
}
}
}
}struct SharePhotoView: View {
@State private var showMessage = false
let image: UIImage
var body: some View {
Button("Send Photo") {
guard MFMessageComposeViewController.canSendText(),
MFMessageComposeViewController.canSendAttachments() else {
return
}
showMessage = true
}
.sheet(isPresented: $showMessage) {
MessageComposer(
recipients: [],
body: "Check out this photo!",
attachments: [
MessageAttachment(
data: image.jpegData(compressionQuality: 0.8) ?? Data(),
typeIdentifier: "public.jpeg",
filename: "photo.jpg"
)
]
)
}
}
}canSendText() before presenting. The app crashes if MFMessageComposeViewController is presented on a device that cannot send texts (e.g., iPod touch without iMessage).canSendAttachments() before adding attachments. Not all devices or carriers support MMS attachments.MFMessageComposeViewControllerDelegate, not MFMessageComposeDelegate. It has a single required method.MFMailComposeViewController, the message composer API does not support changing fields after the controller is shown.canSendText() returns false on the simulator. Test on a physical device.Docs: MFMessageComposeViewController | MFMessageComposeViewControllerDelegate
skills
accessorysetupkit
references
activitykit
references
adattributionkit
references
alarmkit
references
app-clips
app-intents
references
app-store-optimization
app-store-review
apple-on-device-ai
appmigrationkit
references
audioaccessorykit
references
authentication
references
avkit
references
background-processing
references
browserenginekit
references
callkit
references
carplay
references
cloudkit
references
contacts-framework
references
core-bluetooth
references
core-data
core-motion
references
core-nfc
references
coreml
references
cryptokit
references
cryptotokenkit
references
debugging-instruments
device-integrity
references
dockkit
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energykit
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eventkit
references
financekit
references
focus-engine
gamekit
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healthkit
references
homekit
references
ios-accessibility
ios-localization
ios-networking
ios-simulator
references
mapkit
metrickit
references
musickit
references
natural-language
references
paperkit
references
passkit
references
pdfkit
references
pencilkit
references
permissionkit
references
photokit
push-notifications
realitykit
references
relevancekit
references
scenekit
references
sensorkit
references
speech-recognition
spritekit
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storekit
swift-api-design-guidelines
swift-architecture
swift-charts
references
swift-codable
swift-concurrency
swift-formatstyle
swift-language
swift-security
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swiftdata
swiftlint
swiftui-animation
swiftui-gestures
references
swiftui-layout-components
swiftui-liquid-glass
references
swiftui-patterns
swiftui-performance
swiftui-uikit-interop
swiftui-webkit
tabletopkit
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tipkit
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vision-framework
weatherkit
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widgetkit
references