Explore the various UI frameworks available for building app interfaces. Discuss the use cases for different frameworks, share best practices, and get help with specific framework-related questions.

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Force NSDocument save panel to select most specific type in format popup button
My app supports different plain text file formats, including the standard .txt and Markdown. When creating a new document, my app already asks which format it should have, so when saving it, I would expect that the save panel already selects that format in the popup button, but currently it always selects "Plain Text". For example, I would expect for a Markdown document that it selects "Markdown" instead of "Plain Text". Is there a way to force it to select the most specific format matching the document format?
Topic: UI Frameworks SubTopic: AppKit Tags:
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Jul ’25
My app doesn't respond on iPhone Air iOS 26.1.
My app doesn't respond on iPhone Air iOS 26.1. After startup, my app shows the main view with a tab bar controller containing 4 navigation controllers. However, when a second-level view controller is pushed onto any navigation controller, the UI freezes and becomes unresponsive. The iPhone simulator running iOS 26.1 exhibits the same problem. The debug profile shows CPU usage at 100%. However, other devices and simulators do not have this problem.
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Preview crashes when using ForEach with a Binding to an array and generics
The following repro case results in a previews crash on Xcode 26 beta 3 (report attached). FB18762054 import SwiftUI final class MyItem: Identifiable, Labelled { var label: String init(_ label: String) { self.label = label } } protocol Labelled { var label: String { get } } struct HelloView: View { let label: String var body: some View { Text(label) } } struct ListView<Element: Labelled & Identifiable>: View { @Binding var elements: [Element] var body: some View { List { ForEach($elements, id: \.id) { $element in HelloView(label: element.label) // crash // Replacing the above with a predefined view works correctly // Text(element.label) } } } } struct ForEachBindingRepro: View { @State var elements: [MyItem] = [ MyItem("hello"), MyItem("world"), ] var body: some View { ListView(elements: $elements) } } #Preview("ForEachBindingRepro") { ForEachBindingRepro() } foreachbindingrepro-2025-07-12-020628.ips
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Jul ’25
iOS 18 SwiftUI navigation bar problem
Okay I know, fill a bug... but here is a super simple app that will demostrate that the navigation bar chnages from Dark scheme to light scheme when you tap back after it goes to the second view. import SwiftUI struct ContentView: View { var body: some View { NavigationStack { NavigationLink { Text("Tap back and notice the navigation title changes to black text instead of white") .toolbarBackground(.visible, for: .navigationBar) .toolbarBackground(Color.orange, for: .navigationBar) .toolbarColorScheme(.dark, for: .navigationBar) } label: { VStack { Text("First page is the sweetest") } .padding() } .navigationTitle("First Page") .toolbarBackground(.visible, for: .navigationBar) .toolbarBackground(Color.orange, for: .navigationBar) .toolbarColorScheme(.dark, for: .navigationBar) } } } #Preview { ContentView() }
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Feb ’25
Screenshot preventing
I’d like to know if Apple currently supports any public API or entitlement for blocking in-app screenshots on iOS. If no such API exists, what is the officially recommended approach for App Store apps to prevent or react to screenshots of sensitive content in a banking app? I have tried using a hidden UITextField with isSecureTextEntry = true and observing UIApplication.userDidTakeScreenshotNotification, but these methods do not block the initial screenshot. Could you please advise how to block screenshots in my app?
Topic: UI Frameworks SubTopic: UIKit
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Jun ’25
UITabBar Appears During Swipe-Back Gesture on iOS 26 Liquid Glass UI
Hello, While integrating the Liquid Glass UI introduced in iOS 26 into my existing app, I encountered an unexpected issue. My app uses a UITabBarController, where each tab contains a UINavigationController, and the actual content resides in each UIViewController. Typically, I perform navigation using navigationController?.pushViewController(...) and hide the TabBar by setting vc.hidesBottomBarWhenPushed = true when needed. This structure worked perfectly fine prior to iOS 26, and I believe many apps use a similar approach. However, after enabling Liquid Glass UI, a problem occurs. Problem Description From AViewController, I push BViewController with hidesBottomBarWhenPushed = true. BViewController appears, and the TabBar is hidden as expected. When performing a swipe-back gesture, as soon as AViewController becomes visible, the TabBar immediately reappears (likely due to A’s viewWillAppear). The TabBar remains visible for a short moment even if the gesture is canceled — during that time, it is also interactable. Before iOS 26, the TabBar appeared synchronized with AViewController and did not prematurely show during the swipe transition. Tried using the new iOS 18 API: tabBarController?.setTabBarHidden(false, animated: true) It slightly improves the animation behavior, but the issue persists. If hidesBottomBarWhenPushed is now deprecated or discouraged, migrating entirely to setTabBarHidden would require significant refactoring, which is not practical for many existing apps. Is this caused by a misuse of hidesBottomBarWhenPushed, or could this be a regression or design change in iOS 26’s Liquid Glass UI?
Topic: UI Frameworks SubTopic: UIKit Tags:
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Incorrect system color on popover view, and does not update while switching dark mode on iOS 26 beta 3
All system colors are displayed incorrectly on the popover view. Those are the same views present as a popover in light and dark mode. And those are the same views present as modal. And there is also a problem that when the popover is presented, switching to dark/light mode will not change the appearance. That affected all system apps. The following screenshot is already in dark mode. All those problem are occured on iOS 26 beta 3.
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Liquid Glass TabBar animations causes Hangs, bug with UIKitCore?
With iOS 26.1 we started seeing a bug that only appears on iPhone Air. This bug is visible with simulators too. I have tried so many different ways to fix the issue, but Instruments Profiler is pointing at UIKitCore. We load a tab bar, when the user attempts to switch a tab, the app hangs and never recovers. It happens right as the animation of the Glass bubble is in progress. I have tried a UIKit Tab bar, a SwiftUI Tab bar. I tore out AppDelegate and did a direct @main SwiftUI entry for my application. This issue appears with every tab bar instance I try. I attempted to disable LiquidGlass by utilizing this flag UIDesignRequiresCompatibility in my plist, but the flag seems to be ignored by the system. I am not sure what else to try. I have a trace file if that is helpful. What else can I upload? Here is what the code looks like. struct ContentView: View { @State private var selectedTab = 2 var body: some View { TabView(selection: $selectedTab) { Text("Profile") .tabItem { Label("Me", systemImage: "person") } .tag(0) Text("Training") .tabItem { Label("Training", systemImage: "calendar") } .tag(1) Text("Home") .tabItem { Label("Home", systemImage: "house") } .tag(2) Text("Goals") .tabItem { Label("Goals", systemImage: "target") } .tag(3) Text("Coach") .tabItem { Label("Coach", systemImage: "person.2") } .tag(4) } } } #Preview { ContentView() } and AppView entry point import SwiftUI @main struct RunCoachApp: App { var body: some Scene { WindowGroup { ContentView() } } }
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Can I tell when my iOS Widget is running on MacOS (when Use IPhone Widgets is on)
I have an iOS Widget that also can load on the Mac when the Use iPhone Widgets setting is turned on on the Mac in Desktop & Dock. I want to use a different url scheme to open video clips from the widget if it is being clicked on iOS or the Mac. I tried using ProcessInfo.processInfo.isiOSAppOnMac but it always thinks it is on iOS. I also tried looking for the user document path to see if it was /var/mobile/ or /Users/. but it always thinks it is /var/mobile. I assume this is as it is not really a catalyst app but a WidgetKit extension from the phone. Is there anyway I can figure out when the widget is running on the mac? Thanks!
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Jun ’25
Why my app clips is Unavailable
My App Clip is associated with three domains: • nfc.ttwifi.net • qr.ttwifi.net Currently, I’m experiencing an issue where scanning a QR code from qr.ttwifi.net correctly launches my App Clip. However, when I scan a QR code from nfc.ttwifi.net, it successfully displays the App Clip card but then shows the message “App Clip unavailable.” I checked the Website Status in App Store Connect, and both domains have their Debugging Status and Cache Status marked as Verified. One important detail to note: Yesterday, while submitting a new version for review, I noticed that nfc.ttwifi.net showed “Unable to connect to AASA file” in the Cache Status in App Store Connect. The cache status update time was March 27, 2025, at 6:52 PM. However, when I checked today, both domains appeared to be fine, and the cache status update time was March 27, 2025, at 7:07 PM. How can I restore the App Clip functionality for my nfc.ttwifi.net domain?
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Apr ’25
UIAlertController sometimes does not call its UIAlertAction handler
The iOS app that I’m helping to develop displays the following behavior, observed on an iPad Pro (4th generation) running iOS 18.1.1: The app uses UIAlertController to show an action sheet with two buttons (defined by two UIAlertAction objects). Each button has a handler block, and the first thing each handler does is to log that it was called. When the user taps one of the buttons and the action sheet disappears, most of the time the appropriate UIAlertAction handler is called. But sometimes there is no log entry for either of the action handlers, nor does the app do anything else associated with the chosen button, in which case I conclude that the handler was not called. I want to emphasize that I’m describing instances of the same action sheet displayed by the same code. Most of the time the appropriate button handler is called, but sometimes the handler is not called. The uncalled handler problem occurs about once per hour during normal use of the app. The problem has continued to occur across many weeks of testing. What could cause UIAlertController not to call its action handler?
Topic: UI Frameworks SubTopic: UIKit Tags:
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Apr ’25
SwiftData document based on iOS18 shows blank screen
I have some apps using SwiftData document based. They work as expected under iOS17, but not under iOS18: install the app on a iPad 11 pro (first gen) from my MacBook open the app and open an existing fils (perfect under iOS17) it shows a blank, white screen, no data I can create a new document, blank screen, no data When I open that newly created file on a iOS 17 iPad pro, it works perfect, as expected The apps were created from scratch under macOS 14.7 with the corresponding Xcode/Swift/UI version. iOS devices under iOS17 Are there any known problems with document based SwiftData-apps under iOS18, are there any changes one has to made? Thank You so much for any help!
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Apr ’25
perspectiveTransform causing large memory spike / app being killed
I have a PDF which contains geocoordinates. I'm extracting out that image with the following code (this is for an iOS application): guard let cgDocument = CGPDFDocument(overlay.pdfUrl as CFURL) else { return } guard let cgPage = cgDocument.page(at: 1) else { return } var boundingRect = self.rect(for: overlay.boundingMapRect) let pdfPageRect = cgPage.getBoxRect(.mediaBox) let renderer = UIGraphicsImageRenderer(size: pdfPageRect.size) var img = renderer.image { ctx in UIColor.white.set() ctx.fill(pdfPageRect) ctx.cgContext.translateBy(x: 0.0, y: pdfPageRect.size.height) ctx.cgContext.scaleBy(x: 1.0, y: -1.0) ctx.cgContext.drawPDFPage(cgPage) } Once I have that image, I then need to adjust it to fit the specific coordinate corners. For that, I'm doing the following using a perspectiveTransform: let ciImg = CIImage(image: img)! let perspectiveTransformFilter = CIFilter.perspectiveTransform() perspectiveTransformFilter.inputImage = ciImg perspectiveTransformFilter.topRight = cartesianForPoint(point: ur, extent: boundingRect) perspectiveTransformFilter.topLeft = cartesianForPoint(point: ul, extent: boundingRect) perspectiveTransformFilter.bottomRight = cartesianForPoint(point: lr, extent: boundingRect) perspectiveTransformFilter.bottomLeft = cartesianForPoint(point: ll, extent: boundingRect) let txImg = perspectiveTransformFilter.outputImage! img = UIImage(ciImage: txImg) The original image is 792 x 612 (a landscape PDF) but the boundingRect covering the coordinates is 25625 x 20030. Obviously when I try to draw the image into that bounding box the app runs out of memory (25625 x 20030 x 4 is around 2GB of memory). What I'm struggling with is - how do I correctly scale this image to fit into the bounding box even though the bounding box is, oh, 10x the resolution of the actual device? There's some key CoreGraphics thing I'm sure I'm missing here.
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Sep ’25
Issues with List selection in Sequoia (SwiftUI)
In one of my applications I use several List views with Sections. After upgrading to Sequoia I faced the issue, that after selecting an item, the List suddenly scrolls to a different position. Sometimes the selection even gets out of the view, but in every case a double click just went to the wrong item. At one list I found out, that the issue could be solved after changing the data source. I used a computed property, what seems to be a stupid idea. After changing this it now works. Unfortunately there is another List, where this didn't bring the solution. And unfortunately, I cannot reproduce the issue in a code example. One guess of mine is, that it could be related to the fact, that the rows have different heights (because in some are two lines of text and in some are three). And it seems to happen only in very long lists. It worked perfectly in Sonoma. Does anyone face the same issue?
Topic: UI Frameworks SubTopic: SwiftUI
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Feb ’25
Issue with UIActivityViewController Not Showing X (formerly Twitter) and Facebook Icons When Sharing Images on iOS 26 Beta
I have installed the iOS 26 Beta on my device and conducted a comprehensive functionality test of my iOS application, which I designed and developed. The application includes a feature that allows users to share images directly to X (formerly Twitter) and Facebook. During testing, I encountered an issue where the icons for X (formerly Twitter) and Facebook do not appear in the share dialog, despite both apps being installed on the device. This issue prevents users from sharing images to these platforms directly from the app. Steps to Reproduce: 1.Install iOS 26 Beta on a compatible device. 2.Ensure that both the X (formerly Twitter) and Facebook apps are installed and logged in on the device. 3.Open the iOS application and navigate to the image sharing feature. 4.Attempt to share an image using the share dialog. 5.Observe that the icons for X (formerly Twitter) and Facebook are missing from the share options. Expected Behavior: The share dialog should display icons for X (formerly Twitter) and Facebook, allowing users to share images directly to these platforms. Actual Behavior: The icons for X (formerly Twitter) and Facebook do not appear in the share dialog, preventing direct sharing to these platforms. Code Implementation: I have not implemented any code to exclude X (formerly Twitter) and Facebook from the share options. Below is the relevant code for controlling the share screen: let activityViewController = UIActivityViewController(activityItems: activityItems, applicationActivities: applicationActivities) let excludedTypes = [ UIActivity.ActivityType.assignToContact, UIActivity.ActivityType.print, ] activityViewController.excludedActivityTypes = excludedTypes activityViewController.completionWithItemsHandler = completion self.present(activityViewController, animated: true, completion: nil) As shown in the implementation, there is no exclusion of X (formerly Twitter) and Facebook, yet their icons do not appear in the share dialog.
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Sep ’25
preferredTransition not working when using setViewControllers(_:animated:)
I’m using the new preferredTransition = .zoom(...) API introduced in iOS 18. Here’s a simplified version of what I do on app startup: let listVC = CollectionViewController(collectionViewLayout: layout) let detailVC = DetailViewController() detailVC.preferredTransition = .zoom(sourceViewProvider: { context in let indexPath = IndexPath(row: 0, section: 0) let cell = listVC.collectionView.cellForItem(at: indexPath) return cell }) let nav = UINavigationController() nav.setViewControllers([listVC, detailVC], animated: false) window?.rootViewController = nav window?.makeKeyAndVisible() This is meant to restore the UI state from a previous session — the app should launch directly into the DetailViewController. The Problem When I launch the app with setViewControllers([listVC, detailVC], animated: false), the transition from listVC to detailVC appears correctly (i.e., no animation, as intended), but the drag-to-dismiss gesture does not work. The back button appears, and tapping it correctly triggers the zoom-out transition back to the cell, so the preferredTransition = .zoom(...) itself is properly configured. Interestingly, if I delay the push with a DispatchQueue.main.async and instead do: nav.setViewControllers([listVC], animated: false) DispatchQueue.main.async { nav.pushViewController(detailVC, animated: true) } …then everything works perfectly — including the interactive swipe-to-dismiss gesture — but that introduces an unwanted visual artifact: the user briefly sees the listVC, and then it pushes to detailVC, which I’m trying to avoid. My Question Is there a way to enable the swipe-to-dismiss gesture when using setViewControllers([listVC, detailVC], animated: false) It can be very confusing for users if swipe-to-dismiss only works in certain cases inconsistently. Thanks
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Sep ’25
SwiftUI .destructive alert button in macOS dark mode — poor contrast
Here is a simple view to demonstrate the issue struct ContentView: View { @State private var isPresented = false var body: some View { VStack { Button("Test") { isPresented = true } } .alert("Test", isPresented: $isPresented, actions: { Button("Delete All", role: .destructive) {} }, message: { Text("Are You Sure?") }) .padding() } }``` Which results in ![example alert]("https://developer.apple.com/forums/content/attachment/c6210120-d82e-4df5-a01a-fc5cb168e1bf" "title=Screenshot 2025-09-08 at 08.57.21.png;width=546;height=442") The destructive button is almost unreadable. WCAG score is 1.4, far below the minimum recommended 4.5. I found [this post](https://stackoverflow.com/q/66448869) on SO going back to Big Sur, but not on this forum. Any known workarounds (except for building my own dialogs, which I am trying to avoid)? Using confirmationDialog instead of alert does not make a difference.
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Sep ’25