Construct and manage graphical, event-driven user interfaces for iOS or tvOS apps using UIKit.

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UINavigationController inside singleton
I have a struct that holds an instance of UINavigationController: struct NavigationController { static let shared = UINavigationController() } I use NavigationController.shared to push and pop ViewControllers around the app, rather than using the ViewController's .navigationController property. The issue I'm having is that when I pop I get new instances of my previous ViewController, this is my hierarchy: (0) UIWindow | ---- (1) NavigationController (is set as the UIWindow.rootViewController) | ---- (2) UITabBarController (is set with NavigationController.shared.setViewControllers) | ---- (3) ViewController (HomeVC) (is the first tab of the UITabController) | ---- (4) ViewController (ScanVC) (is pushed into the stack by NavigationController.shared.pushViewController) ---- (5) ViewController (NotificationsVC) ---- (6) ViewController (SettingsVC) I put a print statement in my HomeVC in the viewDidLoad method My understanding is that the viewDidLoad should only be called once in the lifecycle of a ViewController When I go back to the HomeVC from the ScanVC then the print always gets triggered which means I have a new instance of the HomeVC This is the print statement I created inside the viewDidLoad method: print("\(#function) View Did Load, instance: \(self)") Here's the output from going back and forth from the HomeVC to ScanVC: viewDidLoad() View Did Load, instance: <HomeVC: 0x118db0000> viewDidLoad() View Did Load, instance: <HomeVC: 0x118db3100> viewDidLoad() View Did Load, instance: <HomeVC: 0x118db0700> Any one has any suggestions on how to fix this? Because ideally going back to the HomeVC should not instantiate a new ViewController. I tested this on a small test project and viewDidLoad would only be triggered once when the ViewController was instantiated.
Topic: UI Frameworks SubTopic: UIKit Tags:
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253
Mar ’25
UIDocumentInteractionController - delegate methods will not be called
Hello, we are presenting a UIDocumentInteractionController within our app, so the user can share some documents. Sharing basically works but we are facing the problem that the two delegate methods documentInteractionController(UIDocumentInteractionController, willBeginSendingToApplication: String?) and documentInteractionController(UIDocumentInteractionController, didEndSendingToApplication: String?) are never being called. Other delegate methods such as documentInteractionControllerWillBeginPreview(UIDocumentInteractionController) are called just fine. Everything worked as expected when we last checked a year ago or so, but doesn't anymore now, even after updating to the latest iOS 18.3. Does anybody know of a solution for this? For reference, this is the simplified code we are using the reproduce the issue: import UIKit import OSLog class ViewController: UIViewController, UIDocumentInteractionControllerDelegate { let log = Logger(subsystem: "com.me.pdfshare", category: "app") var documentInteractionController: UIDocumentInteractionController! override func viewDidLoad() { super.viewDidLoad() guard let pdfURL = Bundle.main.url(forResource: "test", withExtension: "pdf") else { return } documentInteractionController = UIDocumentInteractionController(url: pdfURL) documentInteractionController.delegate = self documentInteractionController.presentPreview(animated: true) } // MARK: - UIDocumentInteractionControllerDelegate func documentInteractionControllerViewControllerForPreview(_ controller: UIDocumentInteractionController) -> UIViewController { log.notice("documentInteractionControllerViewControllerForPreview") return self } // This will be called. func documentInteractionController(_ controller: UIDocumentInteractionController, willBeginSendingToApplication application: String?) { log.notice("willBeginSendingToApplication") } // This will NOT be called. func documentInteractionController(_ controller: UIDocumentInteractionController, didEndSendingToApplication application: String?) { log.notice("didEndSendingToApplication") } // This will NOT be called. }
Topic: UI Frameworks SubTopic: UIKit Tags:
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582
Mar ’25
WKWebView: Select Text and scroll beyond what's visible
Prime Objective I am trying to have a scroll view with a fixed header, a fixed footer, and a WKWebView in between. Using JavaScript, the height of the webView is determined and set to be large enough to hold the entire content. The Problem When selecting text on the webView, the view does not scroll when the edges are reached (this works if the webView is shown without being embedded in a Scroll view, or if it is the last element) What did I try? I tried reading the scroll view, or adding a gesture recognizer, but all of that does not work because the selection is essentially a system task Sourcecode Sourcecode to demonstrate the issue can be found on GitHub
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Mar ’25
On macOS SwiftUI.TimelineView() inside NSViewController is causing AutoLayout recalculations
I have a complex app that requires the main SwiftUI view of the app to be embedded inside an NSHostingView which is a subview of an NSViewController's view. Then this NSViewController is wrapped using NSViewControllerRepresentable to be presented using SwiftUI's Window. And if I have a TimelineView inside my SwiftUI view hierarchy, it causes constant recalculation of the layout. Here's a simplified demo code: @main struct DogApp: App { private let dogViewController = DogViewController() var body: some Scene { Window("Dog", id: "main") { DogViewControllerUI() } } } private struct DogViewControllerUI: NSViewControllerRepresentable { let dogViewController = DogViewController () func makeNSViewController(context: Context) -> NSViewController { dogViewController } func updateNSViewController(_ nsViewController: NSViewController, context: Context) {} func sizeThatFits(_ proposal: ProposedViewSize, nsViewController: NSViewController, context: Context) -> CGSize? { debugPrint("sizeThatFits", proposal) return nil } } public class DogViewController: NSViewController { public override func viewDidLoad() { super.viewDidLoad() let mainView = MainView() let hostingView = NSHostingView(rootView: mainView) view.addSubview(hostingView) hostingView.translatesAutoresizingMaskIntoConstraints = false hostingView.topAnchor.constraint(equalTo: view.topAnchor).isActive = true hostingView.leadingAnchor.constraint(equalTo: view.leadingAnchor).isActive = true hostingView.trailingAnchor.constraint(equalTo: view.trailingAnchor).isActive = true hostingView.bottomAnchor.constraint(equalTo: view.bottomAnchor).isActive = true } } struct MainView: View { var body: some View { VStack { TimelineView(.animation) { _ in Color.random .frame(width: 100, height: 100) } } } } extension Color { static var random: Color { Color( red: .random(in: 0...1), green: .random(in: 0...1), blue: .random(in: 0...1) ) } } When running it's printing out this repeatedly (multiple times a second). "sizeThatFits" SwiftUI.ProposedViewSize(width: Optional(559.0), height: Optional(528.0)) "sizeThatFits" SwiftUI.ProposedViewSize(width: Optional(0.0), height: Optional(0.0)) "sizeThatFits" SwiftUI.ProposedViewSize(width: Optional(559.0), height: Optional(528.0)) "sizeThatFits" SwiftUI.ProposedViewSize(width: Optional(0.0), height: Optional(0.0)) "sizeThatFits" SwiftUI.ProposedViewSize(width: Optional(559.0), height: Optional(528.0)) "sizeThatFits" SwiftUI.ProposedViewSize(width: Optional(0.0), height: Optional(0.0)) "sizeThatFits" SwiftUI.ProposedViewSize(width: Optional(559.0), height: Optional(528.0)) If I run an equivalent code for an iPad, it only prints twice. If I comment out TimelineView on macOS, then it only prints out the above logs when resizing the app window. The main reason this is an issue is that it's clearly causing dramatic degradation in performance. I was told to submit a bug report after I submitted TSI so a SwiftUI engineer could investigate it. Case-ID: 7461887. FB13810482. This was back in May but I received no response. LLMs are no help, and I've experimented with all sorts of workarounds. My last hope is this forum, maybe someone has an idea of what might be going on and why the recalculation is happening constantly on macOS.
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395
Feb ’25
NSTextAttachment lagging in textkit 2
I have an attributedString with 100 NSTextAttachments(contains image of 400kb). When i scroll the textview, it is lagging, When i did the same in textkit 1, it is butter smooth. It can be because of how textkit 1 & 2 layout the elements. let attachment = NSTextAttachment() attachment.image = UIImage(named: "image2") let attachmentString = NSAttributedString(attachment: attachment) let mutableAttributedString = NSMutableAttributedString(attributedString: textView.attributedText) for _ in 0...100 { mutableAttributedString.append(NSAttributedString(string: "\n")) mutableAttributedString.append(attachmentString) } textView.attributedText = mutableAttributedString How to handle images in textkit 2 so that it feels smooth while scrolling textview?
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499
Feb ’25
Xcode 16: SwiftUI plain Button & UIImageView not working
It looks like Xcode 16 has changed this behaviour so I'm not sure if this is a bug or not. When a SwiftUI Button wraps a UIImageView and the button style is .plain the button doesn't work without setting isUserInteractionEnabled. struct ContentView: View { var body: some View { Button { print("Hello World!") } label: { UITestImage() } .buttonStyle(.plain) } } struct UITestImage: UIViewRepresentable { func makeUIView(context: Context) -> UIImageView { let view = UIImageView() // view.isUserInteractionEnabled = true // Fix view.image = UIImage(systemName: "plus") view.contentMode = .scaleAspectFit view.setContentCompressionResistancePriority(.defaultLow, for: .horizontal) view.setContentCompressionResistancePriority(.defaultLow, for: .vertical) view.layoutMargins = .zero return view } public func updateUIView(_ uiView: UIImageView, context: Context) {} } This feels unexpected, is this a bug?
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1k
Feb ’25
Occasional PDFKit crash at PageLayout::getWordRange(unsigned long, long)
At this line of code (SketchTextSelectionManager.swift:449), sometimes there will be crashes based on crashlytics reports. let selection = pdfPage.selectionForWord(at: location) This is directly calling into PDFKit's PDFPage#selection method: https://developer.apple.com/documentation/pdfkit/pdfpage/selectionforword(at:) Attached the full stacktrace: Crashed: com.apple.root.user-initiated-qos.cooperative 0 CoreGraphics 0x30c968 PageLayout::getWordRange(unsigned long, long) const + 908 1 CoreGraphics 0x30bbc0 PageLayout::getTextRangeIndex(CGPoint, CGPDFSelectionType, SelectionPrecision) const + 2292 2 CoreGraphics 0x44a53c CGPDFSelectionCreateBetweenPointsWithOptions + 384 3 PDFKit 0x8d5f8 -[PDFPage selectionFromPoint:toPoint:type:] + 168 4 PDFKit 0x92040 -[PDFPage _rvItemAtPoint:] + 64 5 PDFKit 0x91f4c -[PDFPage rvItemAtPoint:] + 84 6 PDFKit 0x8caa8 -[PDFPage selectionForWordAtPoint:] + 40 7 MyApp 0x8420e0 closure #1 in SketchTextSelectionManager.startNewTextSelection(pageId:location:) + 449 (SketchTextSelectionManager.swift:449) 8 MyApp 0x841a70 SketchTextSelectionManager.startNewTextSelection(pageId:location:) + 205 (CurrentNoteManager.swift:205) 9 libswift_Concurrency.dylib 0x61104 swift::runJobInEstablishedExecutorContext(swift::Job*) + 252 10 libswift_Concurrency.dylib 0x63a28 (anonymous namespace)::ProcessOutOfLineJob::process(swift::Job*) + 480 11 libswift_Concurrency.dylib 0x611c4 swift::runJobInEstablishedExecutorContext(swift::Job*) + 444 12 libswift_Concurrency.dylib 0x62514 swift_job_runImpl(swift::Job*, swift::SerialExecutorRef) + 144 13 libdispatch.dylib 0x15d8c _dispatch_root_queue_drain + 392 14 libdispatch.dylib 0x16590 _dispatch_worker_thread2 + 156 15 libsystem_pthread.dylib 0x4c40 _pthread_wqthread + 228 16 libsystem_pthread.dylib 0x1488 start_wqthread + 8 ```
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328
Feb ’25
Random PDFKit crash on text selection
At this line of code (SketchTextSelectionManager.swift:378), sometimes there will be crashes based on crashlytics reports. In the reports, it seems like this only happens for RTL text range. let selection = pdfPage.selection( from: CGPoint(x: fromStart.x + 1, y: fromStart.y - 1), to: CGPoint(x: toEnd.x - 1, y: toEnd.y + 1) ) This is directly calling into PDFKit's PDFPage#selection method: https://developer.apple.com/documentation/pdfkit/pdfpage/selection(from:to:) Attached the full stacktrace: Crashed: com.apple.root.user-initiated-qos.cooperative 0 CoreGraphics 0x30598c PageLayout::convertRTLTextRangeIndexToStringRangeIndex(long) const + 156 1 CoreGraphics 0x44c3f0 CGPDFSelectionCreateBetweenPointsWithOptions + 224 2 PDFKit 0x91d00 -[PDFPage selectionFromPoint:toPoint:type:] + 168 3 MyApp 0x841044 closure #1 in SketchTextSelectionManager.handleUserTouchMoved(_:) + 378 (SketchTextSelectionManager.swift:378) 4 MyApp 0x840cb0 SketchTextSelectionManager.handleUserTouchMoved(_:) + 205 (CurrentNoteManager.swift:205) 5 libswift_Concurrency.dylib 0x60f5c swift::runJobInEstablishedExecutorContext(swift::Job*) + 252 6 libswift_Concurrency.dylib 0x63a28 (anonymous namespace)::ProcessOutOfLineJob::process(swift::Job*) + 480 7 libswift_Concurrency.dylib 0x6101c swift::runJobInEstablishedExecutorContext(swift::Job*) + 444 8 libswift_Concurrency.dylib 0x62514 swift_job_runImpl(swift::Job*, swift::SerialExecutorRef) + 144 9 libdispatch.dylib 0x15ec0 _dispatch_root_queue_drain + 392 10 libdispatch.dylib 0x166c4 _dispatch_worker_thread2 + 156 11 libsystem_pthread.dylib 0x3644 _pthread_wqthread + 228 12 libsystem_pthread.dylib 0x1474 start_wqthread + 8
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308
Feb ’25
Are SwiftUI animations in UIKit & AppKit intentionally deprecated?
Is there some reason UIKit's and AppKit's animate(with:changes:completion:) methods are marked deprecated in iOS 18 when they were also first made available in iOS18? If they are indeed already deprecated, is there a replacement method we are supposed to use? This method allows the developer to use SwiftUI animations to animate UIKit and AppKit views.
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376
Feb ’25
Lazy cell registration causes crash while dequeue the collectionview cell in collectionview
Cell Registration lazy var headerCell: UICollectionView.SupplementaryRegistration<UICollectionReusableView> = .init(elementKind: UICollectionView.elementKindSectionHeader) { supplementaryView, elementKind, indexPath in } and Cell Dequeue datasource.supplementaryViewProvider = { [weak self] collectionView, kind, indexPath in return collectionView.dequeueConfiguredReusableSupplementary(using: headerCell, for: indexPath) } I am registering a collectionview cell or collwctionview reusable view as lazy variable. It causes a crash like Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Attempted to dequeue a supplementary view using a registration that was created inside -collectionView:viewForSupplementaryElementOfKind:atIndexPath: or inside a UICollectionViewDiffableDataSource supplementary view provider. Creating a new registration each time a supplementary view is requested will prevent reuse and cause created supplementary views to remain inaccessible in memory for the lifetime of the collection view. Registrations should be created up front and reused. Registration: <UICollectionViewSupplementaryRegistration: 0x600001798a00>
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370
Feb ’25
iPAD custom in app keyboard stopped responding
IOS 12 - 18.1.1 - objective C, Xcode 16.0 App runs on both iPhone and iPad, this issue only occurs happens on iPads. For the iPhones I am able to get a decent numeric only keyboard to display. I pulled down NumericKeypad from GitHub and used that a model on how to implement a custom keypad. In the inputView of the delegate, a new custom text field is create and then assigned a delegate and other properties then it returns the view to the main ViewController. When the ViewControllers and the correct text field is entered my custom keyboard display and the buttons respond but nothing is displayed in the text field. This has worked for years and all of the sudden it stopped. The original project for the example 10 key custom keyboard builds and when loaded that works on the iPad. If I comment out condition to only execute if running on an iPad and test with an iPhone the keyboards works. It is only on a iPad that this happens. This is the cod that creates creates the keyboard from a .xib file. I am using a storyboard for the main app. #import "Numeric10KeyTextField.h" #import "Numeric10KeyViewController.h" @implementation Numeric10KeyTextField (UIView *)inputView { UIView *view = nil; Numeric10KeyViewController *numVC; // Add hook here for iPhone or other devices if needed but now return nil if iPhone so it uses the default // if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPad) { numVC = [[Numeric10KeyViewController alloc] initWithNibName:@"Numeric10Key" bundle:nil]; [numVC setActionSubviews:numVC.view]; numVC.delegate = self.numeric10KeyDelegate; numVC.numpadTextField = self; view = numVC.view; // } return view; } @end
Topic: UI Frameworks SubTopic: UIKit Tags:
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463
Feb ’25
Does `requestGeometryUpdate()` Override Orientation Lock by Design?
Hi everyone, I've been testing the requestGeometryUpdate() API in iOS, and I noticed something unexpected: it allows orientation changes even when the device’s orientation lock is enabled. Test Setup: Use requestGeometryUpdate() in a SwiftUI sample app to toggle between portrait and landscape (code below). Manually enable orientation lock in Control Center. Press a button to request an orientation change in sample app. Result: The orientation changes even when orientation lock is ON, which seems to override the expected system behavior. Questions: Is this intended behavior? Is there official documentation confirming whether this is expected? I haven’t found anything in Apple’s Human Interface Guidelines (HIG) or UIKit documentation that explicitly states this. Since this behavior affects a system-wide user setting, could using requestGeometryUpdate() in this way lead to App Store rejection? Since Apple has historically enforced respecting user settings, I want to clarify whether this approach is compliant. Would love any official guidance or insights from Apple engineers. Thanks! struct ContentView: View { @State private var isLandscape = false // Track current orientation state var body: some View { VStack { Text("Orientation Test") .font(.title) .padding() Button(action: toggleOrientation) { Text(isLandscape ? "Switch to Portrait" : "Switch to Landscape") .bold() .padding() .background(Color.blue) .foregroundColor(.white) .cornerRadius(10) } } } private func toggleOrientation() { guard let scene = UIApplication.shared.connectedScenes.first as? UIWindowScene else { print("No valid window scene found") return } // Toggle between portrait and landscape let newOrientation: UIInterfaceOrientationMask = isLandscape ? .portrait : .landscapeRight let geometryPreferences = UIWindowScene.GeometryPreferences.iOS(interfaceOrientations: newOrientation) scene.requestGeometryUpdate(geometryPreferences) { error in print("Failed to change orientation: \(error.localizedDescription)") } self.isLandscape.toggle() } }
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401
Feb ’25
Mac Catalyst: Presenting view controller <UIAlertController:> from detached view controller <MyViewController:> is not supported, and may result in incorrect safe area insets and a corrupt root presentation on Sonoma
Okay so I'm getting this log every time I present a UIAlertController: Mac Catalyst: Presenting view controller <UIAlertController: 0x10f027000> from detached view controller <MyViewController: 0x10d104080> is not supported, and may result in incorrect safe area insets and a corrupt root presentation. Make sure <MyViewController: 0x10d104080> is in the view controller hierarchy before presenting from it. Will become a hard exception in a future release. A few points: MyViewController is not detached and the presentation shows just fine. I specifically check for this before presenting the alert controller like so: BOOL okayToPresentError = (self.isViewLoaded && self.view.window != nil); if (okayToPresentError) { [self presentErrorInAlertController:error]; } else { //Wait until view did appear. self.errorToPresentInViewDidAppear = error; } It spews out every time an error is fed back to my app and I present the alert controller (I can turn off the network connection and I show an alert controller with a "retry" button in it which will loop the error back so I can replay the error alert presentation over and over again) . Every time the alert controller is presented, I get this spewing in the console. Please don't start throwing hard exceptions because the check is faulty.
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2.3k
Feb ’25
.fileImporter not working on iPhone
I've been running into an issue using .fileImporter in SwiftUI already for a year. On iPhone simulator, Mac Catalyst and real iPad it works as expected, but when it comes to the test on a real iPhone, the picker just won't let you select files. It's not the permission issue, the sheet won't close at all and the callback isn't called. At the same time, if you use UIKits DocumentPickerViewController, everything starts working as expected, on Mac Catalyst/Simulator/iPad as well as on a real iPhone. Steps to reproduce: Create a new Xcode project using SwiftUI. Paste following code: import SwiftUI struct ContentView: View { @State var sShowing = false @State var uShowing = false @State var showAlert = false @State var alertText = "" var body: some View { VStack { VStack { Button("Test SWIFTUI") { sShowing = true } } .fileImporter(isPresented: $sShowing, allowedContentTypes: [.item]) {result in alertText = String(describing: result) showAlert = true } VStack { Button("Test UIKIT") { uShowing = true } } .sheet(isPresented: $uShowing) { DocumentPicker(contentTypes: [.item]) {url in alertText = String(describing: url) showAlert = true } } .padding(.top, 50) } .padding() .alert(isPresented: $showAlert) { Alert(title: Text("Result"), message: Text(alertText)) } } } DocumentPicker.swift: import SwiftUI import UniformTypeIdentifiers struct DocumentPicker: UIViewControllerRepresentable { let contentTypes: [UTType] let onPicked: (URL) -> Void func makeCoordinator() -> Coordinator { Coordinator(self) } func makeUIViewController(context: Context) -> UIDocumentPickerViewController { let documentPicker = UIDocumentPickerViewController(forOpeningContentTypes: contentTypes, asCopy: true) documentPicker.delegate = context.coordinator documentPicker.modalPresentationStyle = .formSheet return documentPicker } func updateUIViewController(_ uiViewController: UIDocumentPickerViewController, context: Context) {} class Coordinator: NSObject, UIDocumentPickerDelegate { var parent: DocumentPicker init(_ parent: DocumentPicker) { self.parent = parent } func documentPicker(_ controller: UIDocumentPickerViewController, didPickDocumentsAt urls: [URL]) { print("Success!", urls) guard let url = urls.first else { return } parent.onPicked(url) } func documentPickerWasCancelled(_ controller: UIDocumentPickerViewController) { print("Picker was cancelled") } } } Run the project on Mac Catalyst to confirm it working. Try it out on a real iPhone. For some reason, I can't attach a video, so I can only show a screenshot
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461
Feb ’25
Performing simulations in the UI elements in uikit
I wanted to perform simulation in my application as a self tour guide for my user. For this I want to programatically simulate various user interaction events like button click, keypress event in the UITextField or moving the cursor around in the textField. These are only few examples to state, it can be any user interaction event or other events. I wanted to know what is the apple recommendation on how should these simulations be performed? Is there something that apple offers like creating an event which can be directly executed for simulations. Is there some library available for this purpose?
Topic: UI Frameworks SubTopic: UIKit Tags:
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319
Feb ’25
UITabbarController - padOS18: at top, padOS17 and before: at Bottom
This pertains to iPad apps and UITabbarController in UIKit. Our internal app for employees utilizes UITabbarController displayed at the bottom of the screen. Users prefer to maintain consistency with it being at the bottom. It becomes challenging to argue against this when users point out the iPhone version displaying it "correctly" at the bottom. My response is to trust Apple's design team to keep it at the top. One workaround is to develop the app using the previous Xcode version, version 15 (via Xcode Cloud), targeting padOS17. This ensures the tab bar is shown at the bottom of the screen. However, this approach has its drawbacks: Apple may not support it in the future, leading to missed secure updates for the app, among other issues. Exploring the UITabbarController mode appears to be the solution I am seeking. To quote the documentation "on iPad, If the tabs array contains one or more UITabGroup items, the system displays the content as either a tab bar or a sidebar, depending on the context. Otherwise, it only displays the content only as a tab bar.". The part "displays the content only as a tab bar." made think this is BAU: class ViewController: UITabBarController { override func viewDidLoad() { super.viewDidLoad() self.mode = .tabBar } } Unfortunately, this does not resolve the issue. Is there an API method that can force the tabbar to its previous bottom position? The app uses multiple windows. When we split a window to launch another instance, the tab bar appears at the bottom. This behavior seems tied to the form factor—or potentially to how many items are in the tab bar. We could build a custom tab bar to override this, but that goes against my “don’t reinvent the wheel” principle. Any comments we welcome and thank you for reading this (to the end) Theo
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501
Feb ’25
Use of SceneDelegate not working
I am trying to configure scenes to capture a redirect URL after a successful login attempt. I am using OAuth code flow. This is the code I have so far: ios_app.swift import SwiftUI @main struct ios_appApp: App { @UIApplicationDelegateAdaptor(AppDelegate.self) var appDelegate let persistenceController = PersistenceController.shared @StateObject private var authState = AuthState() var body: some Scene { WindowGroup { ContentView() .environment(\.managedObjectContext, persistenceController.container.viewContext) .environmentObject(authState) } } } AppDelegate.swift import UIKit import AWSMobileClient import GoogleSignIn class AppDelegate: UIResponder, UIApplicationDelegate { var window: UIWindow? func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool { print("AppDelegate: didFinishLaunchingWithOptions") AWSMobileClient.default().initialize { (userState, error) in if let userState = userState { print("UserState: \(userState)") } else if let error = error { print("Error initializing AWSMobileClient: \(error.localizedDescription)") } } GIDSignIn.sharedInstance.restorePreviousSignIn { user, error in if let error = error { print("Error restoring previous Google Sign-In: \(error.localizedDescription)") } } return true } } SceneDelegate.swift import UIKit import SwiftUI import GoogleSignIn class SceneDelegate: UIResponder, UIWindowSceneDelegate { var window: UIWindow? func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) { print("SceneDelegate: scene willConnectTo") guard let windowScene = (scene as? UIWindowScene) else { print("SceneDelegate: Invalid windowScene") return } let window = UIWindow(windowScene: windowScene) let contentView = ContentView().environmentObject(AuthState()) window.rootViewController = UIHostingController(rootView: contentView) self.window = window window.makeKeyAndVisible() print("SceneDelegate: window initialized and visible") } func sceneDidDisconnect(_ scene: UIScene) { print("SceneDelegate: sceneDidDisconnect") } func sceneDidBecomeActive(_ scene: UIScene) { print("SceneDelegate: sceneDidBecomeActive") } func sceneWillResignActive(_ scene: UIScene) { print("SceneDelegate: sceneWillResignActive") } func sceneWillEnterForeground(_ scene: UIScene) { print("SceneDelegate: sceneWillEnterForeground") } func sceneDidEnterBackground(_ scene: UIScene) { print("SceneDelegate: sceneDidEnterBackground") } func scene(_ scene: UIScene, openURLContexts URLContexts: Set<UIOpenURLContext>) { guard let url = URLContexts.first?.url else { print("SceneDelegate: No URL found in URLContexts") return } print("SceneDelegate: openURLContexts with URL: \(url)") if GIDSignIn.sharedInstance.handle(url) { print("SceneDelegate: Google Sign-In handled URL") return } if url.scheme == "myurlscheme" || (url.scheme == "https" && url.host == "mydomain.com" && url.path == "/mobile-auth-callback") { print("SceneDelegate: Handling auth response for URL: \(url)") AuthService.shared.handleOAuthCallback(url: url) } else { print("SceneDelegate: URL scheme not handled: \(url.scheme ?? "No scheme")") } } func scene(_ scene: UIScene, continue userActivity: NSUserActivity) { print("SceneDelegate: continue userActivity") if userActivity.activityType == NSUserActivityTypeBrowsingWeb { if let url = userActivity.webpageURL { handleUniversalLink(url: url) } } } private func handleUniversalLink(url: URL) { print("SceneDelegate: Handling universal link: \(url)") if url.path.contains("/mobile-auth-callback") { let queryItems = URLComponents(url: url, resolvingAgainstBaseURL: false)?.queryItems let code = queryItems?.first(where: { $0.name == "code" })?.value if let code = code { print("SceneDelegate: Received code: \(code)") AuthService.shared.exchangeCodeForToken(code: code) } else { print("SceneDelegate: No code found, handling email/password callback") AuthService.shared.handleEmailPasswordCallback(url: url) } } } } Also introduced this configuration in Info.plist: <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"> <plist version="1.0"> <dict> <key>UIApplicationSceneManifest</key> <dict> <key>UIApplicationSupportsMultipleScenes</key> <true/> <key>UISceneConfigurations</key> <dict> <key>UIWindowSceneSessionRoleApplication</key> <array> <dict> <key>UISceneConfigurationName</key> <string>Default Configuration</string> <key>UISceneDelegateClassName</key> <string>ios-app.SceneDelegate</string> </dict> </array> </dict> </dict> ...Other parameters </dict> </plist> I am using the simulator to launch my app and can see AppDelegate related logs but I am not seeing any SceneDelegate logs (I suppose because it is not being initialized nor called). I have tried restarting the computer/Xcode, clean and rebuild the application but none of the things I tested work. Is there any part of my code wrong? Any other idea here?
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1k
Feb ’25
UICollectionView.CellRegistration and dequeueConfiguredReusableCell with nil for Item? causes runtime crash
Modern collection views use UICollectionViewDiffableDataSource with UICollectionView.CellRegistration and UICollectionView.dequeueConfiguredReusableCell(registration:indexPath:item). There are runtime crashes when passing nil as argument for the item parameter. There's no clear documentation on whether optional items are allowed or not. The function signature in Swift is: @MainActor @preconcurrency func dequeueConfiguredReusableCell<Cell, Item>(using registration: UICollectionView.CellRegistration<Cell, Item>, for indexPath: IndexPath, item: Item?) -> Cell where Cell : UICollectionViewCell Given the Item? type one would assume Optionals are allowed. In Objective-C the signature is: - (__kindof UICollectionViewCell *)dequeueConfiguredReusableCellWithRegistration:(UICollectionViewCellRegistration *)registration forIndexPath:(NSIndexPath *)indexPath item:(id)item; I'm not sure, if there's implicit nullability bridging to the Swift API or if the Objective-C files has some explicit nullability annotation. The crash is due to a swift_dynamicCast failing with: Could not cast value of type '__SwiftNull' (0x10b1c4dd0) to 'Item' (0x10d6086e0). It's possible to workaround this by making a custom Optional type like enum MyOptional<T> { case nothing case something(T) } and then wrapping and unwrapping Item? to MyOptional<Item>. But this feels like unnecessary boilerplate. With the current situation it's easy to ship an app where everything seems to work, but in production only certain edge cases cause nil values being used and then crashing the app. Please clarify the allowed arguments / types for the dequeueConfiguredReusableCell function. Either Optionals should be supported and not crash at runtime or the signatures should be changed so there's a compile time error, when trying to use an Item?. Feedback: FB16494078
Topic: UI Frameworks SubTopic: UIKit Tags:
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339
Feb ’25
How do I properly mix SwiftUI Views with Auto Layout Constraint animations?
I have a SwiftUI View I've introduced to a UIKit app, using UIHostingController. The UIView instance that contains the SwiftUI view is animated using auto layout constraints. In this code block, when a view controller's viewDidAppear method I'm creating the hosting controller and adding its view as a subview of this view controller's view, in addition to doing the Container View Controller dance. override func viewDidAppear(_ animated: Bool) { super.viewDidAppear(animated) let hostingViewController = UIHostingController(rootView: TestView()) hostingViewController.view.translatesAutoresizingMaskIntoConstraints = false addChild(hostingViewController) view.addSubview(hostingViewController.view) let centerXConstraint = hostingViewController.view.centerXAnchor.constraint(equalTo: view.centerXAnchor) let topConstraint = hostingViewController.view.topAnchor.constraint(equalTo: view.topAnchor) widthConstraint = hostingViewController.view.widthAnchor.constraint(equalToConstant: 361) heightConstraint = hostingViewController.view.heightAnchor.constraint(equalToConstant: 342) NSLayoutConstraint.activate([centerXConstraint, topConstraint, widthConstraint, heightConstraint]) hostingViewController.didMove(toParent: self) self.hostingViewController = hostingViewController } I add a button to the UI which will scale the UIHostingViewController by adjusting its height and width constraints. When it's tapped, this action method runs. @IBAction func animate(_ sender: Any) { widthConstraint.constant = 120.3 heightConstraint.constant = 114.0 UIView.animate(withDuration: 0.5) { self.view.layoutIfNeeded() } } The problem is, the SwiftUI view's contents "jump" at the start of the animation to the final height, then animate into place. I see this both using UIView.animate the UIKit way, or creating a SwiftUI animation and calling `UIView. What else do I need to add to make this animate smoothly?
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492
Feb ’25
How to add tools such as search and setting in new ios TabView?
I want to add a tool bar (setting search )to my app just like the apple file app using pure swiftUI, is it possible, if not, can i using a UIKit to implement it. struct MainView: View { var body: some View { TabView { Tab("View 1", systemImage: "square.grid.3x2") { View1() } Tab("View 2", systemImage: "square.grid.2x2") { View2() } } .tabViewStyle(.sidebarAdaptable) }
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451
Feb ’25