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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NSTextLists not rendered when NSTextContentStorageDelegate textContentStorage (_:, textParagraphWith:) is implemented
I have a UITextView that contains paragraphs with text bullet lists (via NSTextList). I also implement NSTextContentStorageDelegate.textContentStorage(_:, textParagraphWith:) in order to apply some custom attributes to the text without affecting the underlying attributed text. My implementation returns a new NSParagraph that modifies the foreground color of the text. I based this on the example in the WWDC 21 session "Meet Text Kit 2". UITextView stops rendering the bullets when I implement the delegate function and return a custom paragraph. Why? func textContentStorage(_ textContentStorage: NSTextContentStorage, textParagraphWith range: NSRange) -> NSTextParagraph? { guard let originalText = textContentStorage.textStorage?.attributedSubstring(from: range) else { return nil } let updatedText = NSMutableAttributedString(attributedString: originalText) updatedText.addAttribute(.foregroundColor, value: UIColor.green, range: NSRange(location: 0, length: updatedText.length)) let paragraph = NSTextParagraph(attributedString: updatedText) // Verify that the text still contains NSTextList if let paragraphStyle = paragraph.attributedString.attribute(.paragraphStyle, at: 0, effectiveRange: nil) as? NSParagraphStyle { assert(!paragraphStyle.textLists.isEmpty) } else { assertionFailure("Paragraph has lost its text lists") } return paragraph }
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275
May ’25
openURL:options:completionHandler: Not Opening tel:// Link on iPad with Cellular Data
We are using openURL:options:completionHandler: to open a tel:// number in the dialer to place a call. This works on iPhones and WiFi-only iPads (tested with a iPad Mini 6th Gen), but it is failing to open on an iPad 8th Gen (WiFi + Cellular) running iPadOS 18.5 being used by a customer. Prior to updating the iPad to iPadOS 18, the call worked on iPadOS 15.2 and opened the call in FaceTime as expected. Despite not opening the dialer in iPadOS 18, the completionHandler returns the success parameter as true. canOpenUrl also returns true. We created a small test application that reproduces the issue using the code snippet below in a new application, with the tel schema added to the info.plist Queried URL Schemes. We are currently using Xcode 16.3. Test Steps: Create a new blank application and replace ContentView.swift with the code snippet below Run the test app on a physical iPad 8th Gen (WiFi + Cellular) Tap the "place a test call" button Expected Results: The user is prompted to call the number and is taken to FaceTime to attempt the call. The user may then receive an alert telling them an iPhone must be paired if not already. Alternatively: return success = false in the completionHandler. Actual Results: No action occurs that is visible to the user, and the completionHandler returns success = true. Separately, we should be able to have some method of checking if the device can actually complete a call, i.e. if an iPhone is paired, so that we can correctly show or hide a phone icon in the app based on if the user can place a call. canOpenUrl returns true even if there is not a device paired and the call cannot actually be placed, and there doesn't seem to be a proper method for making that check. Code Snippet: import SwiftUI struct ContentView: View { @State private var showAlert = false var body: some View { VStack { Image(systemName: "globe") .imageScale(.large) .foregroundStyle(.tint) Text("Hello, world!") Button("Place a test call") { if let url = URL(string: "tel://5555554567") { UIApplication.shared.open(url) { success in if success { print("Call initiated successfully.") } else { showAlert = true } } } } } .padding() .alert("Call Failed", isPresented: $showAlert) { Button("OK") { showAlert = false } } message: { Text("The call could not be initiated.") } } } #Preview { ContentView() }
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165
Jun ’25
Custom, Markdown autocapitalizationType.
Hi, I've got an app that displays markdown in UITextView / NSTextView. I would like it to behave like Notes app does, that is if user types the line start modifier, e.g: "# " or "> " I would like the keyboard to show a capitalized letters. I've tried looking into overriding insertText - and it breaks the predictive text (can not insert white space). I've tried implementing UITextInputTokenizer but no luck either. Like I said, I see the Notes app does it perfectly, so maybe I'm missing something obvious or there is a way to do it without interrupting the auto-correction and predictive text. Ideally same thing can be applied to the NSTextView as the app support both platforms.
Topic: UI Frameworks SubTopic: UIKit Tags:
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134
May ’25
Xcode 26, macOS 26, attempting to use alternate dock icons
I have added multiple status icons to my project, in the form of .icon files created with Icon Composer. The main app icon works, but the status icons are not working. I am attempting to load the images from the asset catalog using NSImage imageNamed:, and apply them to the NSApp dockTile using NSGlassEffectContainerView. I don't even know if that attempt is going to work, as I never get past the stage of NSImage loading the icons. Maybe someone on the forums knows what to do there? I'd be willing to use one of my coding support incidents to work through this if necessary, as my two incidents will expire as my subscription rolls over in August anyway. My project lives at https://github.com/losnoco/cog/, and the Tahoe attempt WIP lives in the wip.tahoe branch, with the latest commit as of this post being the attempt to adapt the Dock Icon generation. I'd love to know if I can adapt this easily. I'm also still trying to support existing non-Glass custom .png icons the user can add to their profile folder with buttons in the preferences, as well as supporting legacy status icons on pre-Tahoe installs. I also try to add a progress bar to the dock tile view when the app is processing something at length.
Topic: UI Frameworks SubTopic: AppKit Tags:
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239
Jun ’25
detecting modifier keys using UITextFieldDelegate protocol
I have a UITextField in my application, and I want to detect all the keys uniquely to perform all relevant task. However, there is some problem in cleanly identifying some of the keys. I m not able to identify the backspace key press in the textField(_:shouldChangeCharactersIn:replacementString:) method. Also I don't know how to detect the Caps Lock key. I am intending to so this because I want to perform some custom handling for some keys. Can someone help me with what is the way of detecting it under the recommendation from apple. Thanks in advance. Note: checking for replacementString parameter in shouldChangeCharactersIn method for empty does not help for backspace detection as it overlaps with other cases.
Topic: UI Frameworks SubTopic: UIKit Tags:
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150
Mar ’25
progress view does not work
I have an app that run Monte Carlo simulations. I run thousands of simulations in the app and a simulation runs can take on the order of 30 seconds to a minute to complete. I would like to have a progress view that tracks the number of simulation runs. How can I implement this in swiftui?
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174
Mar ’25
Regarding ARKit camera feed zoom and macro support for closer object
I am currently developing an AR experience using ARKit with SceneKit and am looking to implement functionality that enables: Zooming into the AR camera feed, ideally leveraging the ultra-wide or telephoto lenses available on supported devices. Macro-style focus capabilities, allowing users to view and interact with virtual content closely aligned with small or nearby real-world objects (within a few centimeters). My objective is to ensure that ARKit continues to render the scene accurately while enabling a zoomed-in view or macro-level focus for better detail visibility and alignment. Could you please advise on: Whether ARKit currently supports camera zoom or allows access to macro or ultra-wide cameras within an ARSession. Limitations or considerations when using multi-camera setups in conjunction with ARKit. Any guidance or references to documentation or sample code would be greatly appreciated. Best regards, Ayush
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125
May ’25
tvOS: Using .onExitCommand to Navigate to Home Tab Before Exiting — Is This Acceptable?
Hi Apple Developer Team, In my tvOS app built with SwiftUI, I have a tab-based interface with several sections. The first tab (index 0) is the Home tab. Other tabs include Contact, WiFi, Welcome, etc. I want to handle the remote's Menu / Back button (.onExitCommand) so that: If the user is on any tab other than Home (tabs 1, 2, 3, etc.), pressing the Menu button takes them back to the Home tab. If the user is already on the Home tab, then pressing the TV/Home button (not Menu) behaves as expected — suspending or exiting the app (handled by the system, no code involved). Here's a simplified version of what I implemented: .onExitCommand { if selectedTab != 0 { selectedTab = 0 focusedTab = 0 } else { // Let system handle the exit when user presses the TV/Home button } } This behavior ensures users don’t accidentally exit the app when they're browsing other tabs, and provides a consistent navigation experience. Question: Is this an acceptable and App Store-compliant use of .onExitCommand on tvOS? I'm not calling exit(0) or trying to force-terminate the app — just using .onExitCommand for in-app navigation purposes. Any official guidance or best practices would be greatly appreciated! Thanks, Prashant
Topic: UI Frameworks SubTopic: SwiftUI Tags:
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100
May ’25
How to determine which ui control is found first in the view hierarchy, when I assign the same keyboardShortcut () to 2 buttons?
import SwiftUI struct ContentView: View { var body: some View { VStack { Button ("Button 1") { print ("Button 1"); } .keyboardShortcut("k", modifiers: .command) Button ("Button 2") { print ("Button 2"); } .keyboardShortcut("k", modifiers: .command) } } } I the above snippet, I have assigned the same keyboard shortcut (cmd +k) to 2 different buttons. According to the docs, if multiple controls are associated with the same shortcut, the first one found is used. How do I figure out if Button 1 would be found first during the traversal or Button 2 ? Is it based on the order of declaration? Is it always the case that Button 1 would be found first since it was declared before Button 2 ?
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111
Mar ’25
SwiftUI: How do you do CoreData backup and restore?
Hi, I am trying to create a local backup + restore when using SwiftUI and CoreData but I am facing errors left and right. the latest error I am stuck on is: *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'executeFetchRequest:error: A fetch request must have an entity.' Here is what am trying to do: Creating a backup (already solved using NSPersistentStoreCoordinator.migratePersistentStore(_:to:options:type:)) Create a new NSPersistentContainer and call its NSPersistentContainer.loadPersistentStores(completionHandler:) (already solved, load is successful) Update the .environment(.managedObjectContext, viewModel.context) so that SwiftUI uses the new context. (HERE is where the error appears) Any help would be appreciated. Here is some sample code of SwiftUI part of the main view: class ViewModel: ObservableObject { @Published var context: NSManagedObjectContext } @main struct MyApp: App { @StateObject var viewModel: ViewModel var body: some Scene { WindowGroup { ContentView() .environment(\.managedObjectContext, viewModel.context) } } }
Topic: UI Frameworks SubTopic: SwiftUI
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249
Mar ’25
Background or Foreground
Hi Team! Has anyone found a reliable way to detect CarPlay connection without the app needing to be in the foreground? I’m exploring a concept where, for example, as someone nears home while driving, a prompt appears on the CarPlay screen asking “Would you like to turn on the lights / open garage?” triggered by proximity and CarPlay connection. Would be cool to have it work automatically, but knowing you're in the car is kind of important. From what I can see, apps can’t reliably detect CarPlay connection unless they’re actively open on the CarPlay screen. Most background detection methods (like external screen connect notifications) appear deprecated. That is, unless you're specifically approved as a "messaging" or "navigation" app that appear to get special privilages to send alerts from the background. If I send an alert (or poll Carplay periodically) it just gives silent/dead response. Is there any approach, framework, entitlement, or UI pattern that could allow a passive trigger or background detection while driving with CarPlay connected? I can't see any way to bring an app to the foreground either. Not looking to abuse any rules... just want to understand if anyone’s found a clean, approved workaround. Thanks in advance!
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108
Jun ’25
ssue with Session Sharing Between Safari and ASWebAuthenticationSession
We are experiencing an issue with session sharing on iOS and would appreciate your guidance. We operate and control our own OpenID Connect (OIDC) server. Our iOS application uses ASWebAuthenticationSession to authenticate users. We're unable to get the authentication session to be shared between the Safari app and the app's ASWebAuthenticationSession. This results in users having to re-authenticate despite being logged in via Safari. We've attempted various configurations related to cookie SameSite settings. These adjustments resolved the session sharing issue on Android using Chrome Custom Tabs. However, no changes we've tried have enabled session sharing to work as expected on iOS. According to documentation from Apple, Microsoft, Okta, and Auth0, session sharing between Safari and ASWebAuthenticationSession should work. Question: Are there any additional settings, configurations, or platform limitations we should be aware of that could impact session sharing on iOS? Where else can we look to resolve this issue?
Topic: UI Frameworks SubTopic: General
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131
May ’25
Best Way to Help Users Diagnose iOS App Crashes with No UI Feedback
Hi all, We're working on an iOS application and would like to improve our ability to diagnose failures - especially in scenarios where the app crashes before it can present any UI to the user. A few specific questions: In case of an exception or crash, is there a way to log the issue so the user (or our support team) can understand the cause of the failure? If the app crashes abruptly (e.g., due to a runtime exception or crash during launch), is there a recommended way to persist error information before the process terminates? Are there Apple-supported mechanisms (like crash reporting tools or APIs) we can integrate that would help us capture such issues? What’s the best practice for enabling support teams to assist users based on crash reports - especially for crashes that happen before any user interaction? Our goal is to make sure users aren't left in the dark if the app fails to start, and to allow us to deliver timely updates or support based on the cause of the crash. Thanks in advance for your guidance!
Topic: UI Frameworks SubTopic: General Tags:
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104
May ’25
Reliable APIs to check if a Hotkey/Shortcut is already in use?
In our application we have two usecases for a Hotkey/Shortcut identification API/method. We have some predefined shortcuts that will ship with our MacOS application. They may or may not change dynamically, based on what the user has already set as shortcuts/hotkeys, and also to avoid any important system wide shortcuts that the user may or may not have changed. We allow the user to customize the shortcuts/hotkeys in our application, so we want to show what shortcuts the user already has in use system-wide and across their OS experience. This gives rise to the need for an API that lets us know which shortcut/hotkeys are currently being used by the user and also the current system wide OS shortcuts in use. Please let me know if there are any APIs in AppKit or SwiftUI we can use for the above
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248
Mar ’25
Unexpected UINavigationBar Behavior During View Transitions in iOS 18
In iOS 18, I've observed unexpected behavior related to the UINavigationBar when transitioning between view controllers that have differing navigation bar visibility settings. Specifically, when returning from a modal presentation or a web view, the navigation bar reappears with an unexpected height (e.g., 103 points) and lacks content, displaying only an empty bar. Start with a UIViewController (e.g., HomeViewController) where the navigation bar is hidden using: override func viewWillAppear(_ animated: Bool) { super.viewWillAppear(animated) navigationController?.setNavigationBarHidden(true, animated: animated) } Present another UIViewController (e.g., a web view) modally. Dismiss the presented view controller. Observe that upon returning to HomeViewController, the navigation bar is visible with increased height and lacks expected content. Expected Behavior: The navigation bar should remain hidden upon returning to HomeViewController, maintaining the state it had prior to presenting the modal view controller. Actual Behavior: Upon dismissing the modal view controller, the navigation bar becomes visible with an unexpected height and lacks content, leading to a disrupted user interface. Additional Observations: This issue is specific to iOS 18; it does not occur in iOS 17 or earlier versions. The problem seems to stem from setting the navigation bar to be visible in the viewWillDisappear method, as shown below: override func viewWillDisappear(_ animated: Bool) { super.viewWillDisappear(animated) navigationController?.setNavigationBarHidden(false, animated: animated) } Removing or modifying this line mitigates the issue, suggesting a change in the view controller lifecycle behavior in iOS 18. Request for Clarification: Is this change in behavior intentional in iOS 18, or is it a regression? Understanding whether this is a new standard or a bug will help in implementing appropriate solutions. Workaround: As a temporary measure, I've adjusted the navigation bar visibility settings to avoid changing its state in viewWillDisappear, instead managing it in viewWillAppear or viewDidAppear. References: Similar issues have been discussed in the Apple Developer Forums: iPad OS 18 UINavigationBar display incorrectly
Topic: UI Frameworks SubTopic: UIKit
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110
May ’25
Updating sort order of items in a LazyVGrid
I have a grid setup where I'm displaying multiple images which is working fine. Images are ordered by the date they're added, newest to oldest. I'm trying to set it up so that the user can change the sort order themselves but am having trouble getting the view to update. I'm setting the fetch request using oldest to newest as default when initialising the view, then when its appears updating the sort descriptor struct ProjectImagesListView: View { @Environment(\.managedObjectContext) private var viewContext var project : Project let columns = [ GridItem(.flexible()), GridItem(.flexible()), GridItem(.flexible()), GridItem(.flexible()) ] @FetchRequest var pictures: FetchedResults<Picture> var body: some View { ScrollView { LazyVGrid(columns: columns) { ForEach(pictures) { picture in NavigationLink(destination: ProjectImageDetailView(picture: picture)) { if let pictureData = picture.pictureThumbnailData, let uiImage = UIImage(data: pictureData) { Image(uiImage: uiImage) .resizable() .scaledToFit() .frame(height: 100) } else { Image("missing") .resizable() .scaledToFit() .frame(height: 100) } } } } } .navigationBarTitle("\(project.name ?? "") Images", displayMode: .inline) .onAppear() { guard let sortOrder = getSettingForPhotoOrder() else { return } guard let sortOrderValue = sortOrder.settingValue else { return } NSLog("sortOrderPhotos: \(String(describing: sortOrder.settingValue))") if sortOrderValue == "Newest" { NSLog("sortOrderPhotos: Change from default") let newSortDescriptor = NSSortDescriptor(keyPath: \Picture.dateTaken, ascending: false) pictures.nsSortDescriptors = [newSortDescriptor] } } } func getSettingForPhotoOrder() -> Setting? { let fetchRequest: NSFetchRequest<Setting> = Setting.fetchRequest() fetchRequest.predicate = NSPredicate(format: "name = %@", "photoSortOrder") fetchRequest.fetchLimit = 1 do { let results = try viewContext.fetch(fetchRequest) return results.first } catch { print("Fetching Failed") } return nil } init(project: Project) { self.project = project _pictures = FetchRequest( entity: Picture.entity(), sortDescriptors: [ NSSortDescriptor(keyPath: \Picture.dateTaken, ascending: true) ], predicate: NSPredicate(format: "project == %@", project) ) } }
Topic: UI Frameworks SubTopic: SwiftUI
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87
May ’25