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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Foundation (?) mangles diacriticals in Greek Extended (U+1F54)
(NOTE: In sum, this is destructive of user data.) The client is a professor of Classics in constant need of properly-rendered glyphs that represent legitimate code points. As an example, the correct spelling might be: εὔτρητος It is spelled and rendered as intended. A file by this name will be correctly spelled by ls in the Terminal. Note that two diacritics are applied to the second letter, an upsilon (ὔ) However, the Finder displays that file as ἐύτρητος and iterating the string reveals that the accents are improperly distributed over the two. This would never be correct. This handicaps digital-humanities researchers from college to postdoctoral work. A Character by Character iteration demonstrates the mangling.: intended (εὔτρητος) displayed (ἐύτρητος) 3B5 (ε) 1F10 (ἐ) GREEK SMALL LETTER EPSILON, GREEK SMALL LETTER EPSILON WITH PSILI 1F54 (ὔ) 3CD (ύ) GREEK SMALL LETTER UPSILON WITH PSILI AND OXIA GREEK SMALL LETTER UPSILON WITH TONOS 3C4 (τ) 3C4 (τ) (back in sync) 3C1 (ρ) 3C1 (ρ) 3B7 (η) 3B7 (η) 3C4 (τ) 3C4 (τ) 3BF (ο) 3BF (ο) 3C2 (ς) 3C2 (ς) I don't want to muddy the waters by guessing where and how the mistake is made, just see for yourself.
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375
Feb ’25
UINavigtionController as a child view leaves an unwanted gap
I have a situation where I need to add a UINavigationController as a child view controller within another view controller. When I do this, there is a gap between the bottom of the navigation controller's root view controller and the bottom of the navigation controller's own view. This happens even though I am constraining the navigation controller's view to the edges of its superview, not the safe areas. I'd really like to eliminate this gap, but nothing I have tried is working.
Topic: UI Frameworks SubTopic: UIKit Tags:
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240
Mar ’25
@Binding bools within a VStack getting conflated
I am running into an issue where two distinct bool bindings are both being toggled when I toggle only one of them. My component looks like VStack { Checkbox(label: "Checkbox 1", isOn: $stateVar1) Checkbox(label: "Checkbox 2", isOn: $stateVar2) } where my CheckBox component looks like struct Checkbox: View { let label: String @Binding var isOn: Bool var body: some View { Button { isOn.toggle() } label: { HStack { Image(systemName: isOn ? "checkmark.square" : "square") Text(label) } .foregroundStyle(.black) } } } If I click on one checkbox, both of them get toggled. However, if I simply remove the checkboxes from the VStack, then I am able to toggle them both independently. I believe this is a bug with bool Bindings, but if anyone can point out why I am mistaken that would be much appreciated :)
Topic: UI Frameworks SubTopic: SwiftUI
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275
Feb ’25
NSHostingController menu not activated
I'm attempting to write a macOS version of https://stackoverflow.com/a/74935849/2178159. From my understanding, I should be able to set the menu property of an NSResponder and it will automatically show on right click. I've tried a couple things: A: set menu on an NSHostingController's view - when I do this and right or ctrl click, nothing happens. B: set menu on NSHostingController directly - when I do this I get a crash Abstract method -[NSResponder setMenu:] called from class _TtGC7SwiftUI19NSHostingControllerGVS_21_ViewModifier_...__. Subclasses must override C: manually call NSMenu.popup in a custom subclasses of NSHostingController or NSView's rightMouseDown method - nothing happens. extension View { func contextMenu(menu: NSMenu) -> some View { modifier(ContextMenuViewModifier(menu: menu)) } } struct ContextMenuViewModifier: ViewModifier { let menu: NSMenu func body(content: Content) -> some View { Interaction_UI( view: { content }, menu: menu ) .fixedSize() } } private struct Interaction_UI<Content: View>: NSViewRepresentable { typealias NSViewType = NSView @ViewBuilder var view: Content let menu: NSMenu func makeNSView(context: Context) -> NSView { let v = NSHostingController(rootView: view) // option A - no effect v.view.menu = menu // option B - crash v.menu = menu return v.view } func updateNSView(_ nsView: NSViewType, context: Context) { // part of option A nsView.menu = menu } }
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270
Mar ’25
Crash on removal of QLPreviewController and _EXRemoteViewController
I have a controller that displays a pdf using UIDocumentInteractionController as the presented view. When users open it up, it shows fine. User gets the app backgrounded and session timed out. After timed out, when the app is brought to foreground, I bring our loginVC by removing the old VC used to show the UIDocumentInteractionController. All the crashes are happening at this point. I am not able to reproduce it, but our alert systems show we have crashes happening. The code that shows the pdf is straight forward documentViewController = UIDocumentInteractionController() documentViewController?.delegate = self documentViewController?.url = url documentViewController?.presentPreview(animated: true) and we reset it to nil in delegate documentInteractionControllerDidEndPreview Based on the crash trace, it seems like the crash happens when our login VC replaces it and only when pdf was displayed. The reason of stressing ONLY because when we have other viewcontroller present and they are removed in a similar way, we do not see any issue. So we always replace first and then add a new one childViewController.willMove(toParent: nil) childViewController.viewIfLoaded?.removeFromSuperview() childViewController.removeFromParent() addChild(childViewController) view.addSubview(childViewController.view) childViewController.view.frame = view.bounds childViewController.didMove(toParent: self) Raised a ticket with Apple, but I haven't heard back, and it's been a month. Posting here in case anyone experiences the same and has any solutions. I saw some related posts, and solution was to remove the pdf the moment the app goes to the background, but I am trying to find some alternate solution if possible.
Topic: UI Frameworks SubTopic: UIKit
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218
Mar ’25
Setting rounded corners via CAShapeLayer.path looks problematic
class ViewController: UIViewController { override func viewDidLoad() { super.viewDidLoad() view.backgroundColor = .white do { let shapeLayer = CAShapeLayer() shapeLayer.frame = CGRect(x: 50, y: 100, width: 200, height: 108) let path = UIBezierPath(roundedRect: shapeLayer.bounds, cornerRadius: 36) shapeLayer.path = path.cgPath shapeLayer.fillColor = UIColor.orange.cgColor view.layer.addSublayer(shapeLayer) } do { let layer = CALayer() layer.backgroundColor = UIColor.blue.cgColor layer.cornerRadius = 36 layer.frame = CGRect(x: 50, y: 300, width: 200, height: 108) view.layer.addSublayer(layer) } } } The corner radius is set to 36 through CAShapeLayer, but the actual effect is larger than 36, close to half of the height. Setting it through CALayer is fine Can anyone explain it to me? Thank you
Topic: UI Frameworks SubTopic: UIKit Tags:
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314
Feb ’25
UITabbarController issue on iOS 18
I'm building an app using UITabbarController with 2 tabs: screen A and B. When standing on tab B and I taps on tab A, the order in which the events are triggered will be: For iOS < 18: viewWillDisappear() of screen B tabBarController(_:didSelect:) of UITabbarController For iOS >= 18: tabBarController(_:didSelect:) of UITabbarController viewWillDisappear() of screen B So my question is this an issue or a new update from Apple on iOS 18.*?
Topic: UI Frameworks SubTopic: UIKit Tags:
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391
Mar ’25
UIDocumentPickerViewController of type pdf cannot pick pdf in simulator
I'm having this problem, with this code: let docPicker = UIDocumentPickerViewController(forOpeningContentTypes: [ .pdf ]) docPicker.delegate = self docPicker.modalPresentationStyle = .currentContext view.window?.rootViewController?.present(docPicker, animated: true, completion: nil) but then when I open the simulator and click the button that calls to the method that has this code... Cannot pick the pdf document. Testing in browserstack with real devices is working, but it's a very slow process, why I cannot use simulators to make work this?
Topic: UI Frameworks SubTopic: UIKit Tags:
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363
Feb ’25
Reduce padding, spacing between list section header and search bar
Anyone know how to reduce the padding between list section header (plain style) and search bar? I have tried all available method on google but none work. The default list style does not have this big padding/space between the section header and the search bar. struct Demo: View { @State private var searchText: String = "" var body: some View { NavigationStack { List { Section { ForEach(0..<100) { index in Text("Sample value for \(index)") } } header: { Text("Header") .font(.headline) } } .listStyle(.plain) .navigationTitle("Demo") .navigationBarTitleDisplayMode(.inline) .searchable(text: $searchText) } } }
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248
Feb ’25
iOS App Crashes with SIGABRT and XCTest.framework Not Loaded (Xcode 16.2, SwiftUI 6)
Hello Apple Developer Community, I’m experiencing an issue with my iOS app, "WaterReminder," where it builds successfully in Xcode 16.2 but crashes immediately upon launch in the iPhone 16 Pro Simulator running iOS 18.3.1. The crash is accompanied by a "Thread 1: signal SIGABRT" error, and the Xcode console logs indicate a dyld error related to XCTest.framework/XCTest not being loaded. I’ve tried several troubleshooting steps, but the issue persists, and I’d appreciate any guidance or insights from the community. Here are the details: Environment: Xcode Version: 16.2 Simulator: iPhone 16 Pro, iOS 18.3.1 App: WaterReminder (written in SwiftUI 6) Build Configuration: Debug Issue Description: The app builds without errors, but when I run it in the iPhone 16 Pro Simulator, it shows a white screen and crashes with a SIGABRT signal. The Xcode debugger highlights the issue in the main function or app delegate, and the console logs show the following error: dyld[7358]: Library not loaded: @rpath/XCTest.framework/XCTest Referenced from: <549B4D71-6B6A-314B-86BE-95035926310E> /Users/faytek/Library/Developer/CoreSimulator/Devices/2A51383F-D8EA-4750-AE22-4CDE745164CE/data/Containers/Bundle/Application/56D8B44F-6613-4756-89F0-CB33991F0821/WaterReminder.app/WaterReminder.debug.dylib Reason: tried: '/Users/faytek/Library/Developer/Xcode/DerivedData/WaterReminder-cahqrulxghamvyclxaozotzrbsiz/Build/Products/Debug-iphonesimulator/XCTest.framework/XCTest' (no such file), '/Users/faytek/Library/Developer/CoreSimulator/Devices/2A51383F-D8EA-4750-AE22-4CDE745164CE/data/Containers/Bundle/Application/56D8B44F-6613-4756-89F0-CB33991F0821/WaterReminder.app/Frameworks/XCTest.framework/XCTest' (no such file), '/Users/faytek/Library/Developer/CoreSimulator/Devices/2A51383F-D8EA-4750-AE22-4CDE745164CE/data/Containers/Bundle/Application/56D8B44F-6613-4756-89F0-CB33991F0821/WaterReminder.app/XCTest.framework/XCTest' (no such file), '/Users/faytek/Library/Developer/CoreSimulator/Devices/2A51383F-D8EA-4750-AE22-4CDE745164CE/data/Containers/Bundle/Application/56D8B44F-6613-4756-89F0-CB33991F0821/WaterReminder.app/Frameworks/XCTest.framework/XCTest' (no such file), '/Users/faytek/Library/Developer/CoreSimulator/Devices/2A51383F-D8EA-4750-AE22-4CDE745164CE/data/Containers/Bundle/Application/56D8B44F-6613-4756-89F0-CB33991F0821/WaterReminder.app/XCTest.framework/XCTest' (no such file), '/Users/faytek/Library/Developer/CoreSimulator/Devices/2A51383F-D8EA-4750-AE22-4CDE745164CE/data/Containers/Bundle/Application/56D8B44F-6613-4756-89F0-CB33991F0821/WaterReminder.app/Frameworks/XCTest.framework/XCTest' (no such file), '/Library/Developer/CoreSimulator/Volumes/iOS_22D8075/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS 18.3.simruntime/Contents/Resources/RuntimeRoot/System/Library/Frameworks/XCTest.framework/XCTest' (no such file) What I’ve Tried: ◦ Verified that FBSnapshotTestCase is correctly added to the "Embed Frameworks" build phase. ◦ Confirmed that the Framework Search Paths in build settings point to the correct location. ◦ Ensured that all required frameworks are available in the dependencies folder. ◦ Cleaned the build folder (Shift + Option + Command + K) and rebuilt the project. ◦ Checked the target configuration to ensure XCTest.framework isn’t incorrectly linked to the main app target (it’s only in test targets). ◦ Updated Xcode and the iOS Simulator to the latest versions. ◦ Reset the simulator content and settings. Despite these steps, the app continues to crash with the same dyld error and SIGABRT signal. I suspect there might be an issue with how XCTest.framework is being referenced or loaded in the simulator, possibly related to using SwiftUI 6, but I’m unsure how to resolve it. Could anyone provide advice on why XCTest.framework is being referenced in my main app (since it’s not intentionally linked there) or suggest additional troubleshooting steps? I’d also appreciate any known issues or workarounds specific to Xcode 16.2, iOS 18.3.1, and SwiftUI 6. Thank you in advance for your help! Best regards, Faycel
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656
Mar ’25
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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248
Mar ’25
ActiveLabel
Hey Everyone, I can't see to ActiveLabel as it says there is no active module. Please help me. Thanks, Ben import UIKit import ActiveLabel protocol TweetCellDelegate: AnyObject { func handleProfileImageTapped(_ cell: TweetCell) func handleReplyTapped(_ cell: TweetCell) func handleLikeTapped(_ cell: TweetCell) } class TweetCell: UICollectionViewCell {
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261
Mar ’25
App Download Banner in App Clip downloads but does NOT open app
In our app clip, we open/show the full app download banner. We used to have the expected behavior, but with seemingly no changes to the app download banner code we have the following issue. Expected behavior: App download banner shows in app clip, user presses "Get" button, app is downloaded and installs, "Get" button changes to "Open" button (note: button is blue), user presses "Open" button and the full app is opened. Current behavior: App download banner shows in app clip, user presses "Get" button, app is downloaded and installs, "Get" button changes to "Open" button (note: button is now grey), user presses "Open" button but nothing happens. With the current behavior, the full app is correctly downloaded and the appclip removes itself from the phone, but the open button does nothing.
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371
Feb ’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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352
Mar ’25
SwiftData integration for coexistence with CoreData Error: Persistent truncated
When integrating SwiftData for an already existing app that uses CoreData as data management, I encounter errors. When building the ModelContainer for the first time, the following error appears: Error: Persistent History (184) has to be truncated due to the following entities being removed (all Entities except for the 2 where I defined a SwiftData Model) class SwiftDataManager: ObservableObject { static let shared = SwiftDataManager() private let persistenceManager = PersistenceManager.shared private init(){} lazy var modelContainer: ModelContainer = { do { let storeUrl = persistenceManager.storeURL() let schema = Schema([ HistoryIncident.self, HistoryEvent.self ]) let modelConfig = ModelConfiguration(url: storeUrl) return try ModelContainer(for: schema, configurations: [modelConfig]) } catch { fatalError("Could not create ModelContainer: \(error)") } }() } @Model public class HistoryIncident { var missionNr: String? @Relationship(deleteRule: .cascade) var events: [HistoryEvent]? public init(){} } @Model class HistoryEvent { var decs: String? var timestamp: Date? init(){} } As soon as I call the following function. func addMockEventsToCurrentHistorie() { var descriptor = FetchDescriptor<HistoryIncident>() let key = self.hKey ?? "" descriptor.predicate = #Predicate { mE in key == mE.key } let historyIncident = try? SwiftDataManager.shared.modelContext.fetch(descriptor).first guard var events = historyIncident?.events else {return} events.append(contentsOf: createEvents()) } I get the error: CoreData: error: (1) I/O error for database at /var/mobile/Containers/Data/Application/55E9D59D-48C4-4D86-8D9F-8F9CA019042D/Library/ Private Documents/appDatabase.sqlite. SQLite error code:1, 'no such column: t0.Z1EVENTS' /var/mobile/Containers/Data/Application/55E9D59D-48C4-4D86-8D9F-8F9CA019042D/Library/ Private Documents/appDatabase.sqlite. SQLite error code:1, 'no such column: t0.Z1EVENTS' with userInfo of { NSFilePath = "/var/mobile/Containers/Data/Application/55E9D59D-48C4-4D86-8D9F-8F9CA019042D/Library/ Private Documents/appDatabase.sqlite"; NSSQLiteErrorDomain = 1; }
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668
Feb ’25
Apple Maps annotations and markers
In Apple's Maps app, an annotation is made up of a circle shape or rounded rectangles with a glyph-image. When selecting an annotation, the annotation animates into a balloon marker (see attached GIF). How does Apple Maps solve this - from custom annotation to balloon marker with spring animation? I switched my Maps implementation from SwiftUI to UIKit with a UIViewRepresentable to support annotation clustering - and it works beautifully. But how to subclass an MKAnnotationView (or MKMarkerAnnotationView <- the balloon) to enable selection and animation as in Apple Maps? MKMarkerAnnotationView only show balloon markers and I tried everything inside MKAnnotationView (CALayer, etc.)
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431
Feb ’25
iOS document based app problem running on Mac (Designed for iPad)
Please can somebody help me? I have a document-based iOS in the App Store (iNetWorth). I was able to run it on my M1 Mac Mini as a Mac (Designed for iPad) app without any issues until macOS 15. So, I created a simple test app based on a TabView to try and find out why I cannot get iNetWorth to run successfully on my Mac. The issue is that when TabViewApp.swift file looks like this: import SwiftUI @main struct TabViewApp: App { var body: some Scene { /*WindowGroup { ContentView() }*/ DocumentGroup(newDocument: TextFile()) { file in ContentView(document: file.$document) } } } TabView fails to load the ContentView() - in Xcode 16.2 running on macOS 15.3.2. On opening, the TabView app prompts the user to open a new or existing file normally but it then opens a window that is empty, apart from a Documents button and a label displaying the filename with a dropdown menu (Duplicate, Move, Rename..., Export As…). If the @Binding var document: TextFile line is removed from the ContentView() and the TabViewApp.swift file is changed to: import SwiftUI @main struct TabViewApp: App { var body: some Scene { WindowGroup { ContentView() } /*DocumentGroup(newDocument: TextFile()) { file in ContentView(document: file.$document) }*/ } } the TabView app loads and displays the ContentView() correctly. Both versions of TabView, when running in Xcode on My Mac (Designed for iPad), produce these warnings: CLIENT: Failure to determine if this machine is in the process of shutting down, err=1/Operation not permitted LSPrefs: could not find untranslocated node for &lt;FSNode 0x6000013901a0&gt; { isDir = ?, path = '/private/var/folders/3f/8788c4dj50q050_4wg9fssbr0000gp/X/518B55E1-0EC4-5D84-9202-4E44410EB249/d/Wrapper/TabView.app' }, proceeding on the assumption it is not translocated: Error Domain=NSPOSIXErrorDomain Code=1 "Operation not permitted" LSPrefs: could not find untranslocated node for &lt;FSNode 0x6000013901a0&gt; { isDir = ?, path = '/private/var/folders/3f/8788c4dj50q050_4wg9fssbr0000gp/X/518B55E1-0EC4-5D84-9202-4E44410EB249/d/Wrapper/TabView.app' }, proceeding on the assumption it is not translocated: Error Domain=NSPOSIXErrorDomain Code=1 "Operation not permitted" LSPrefs: could not find untranslocated node for &lt;FSNode 0x6000013901a0&gt; { isDir = ?, path = '/private/var/folders/3f/8788c4dj50q050_4wg9fssbr0000gp/X/518B55E1-0EC4-5D84-9202-4E44410EB249/d/Wrapper/TabView.app' }, proceeding on the assumption it is not translocated: Error Domain=NSPOSIXErrorDomain Code=1 "Operation not permitted" LSPrefs: could not find untranslocated node for &lt;FSNode 0x6000013901a0&gt; { isDir = ?, path = '/private/var/folders/3f/8788c4dj50q050_4wg9fssbr0000gp/X/518B55E1-0EC4-5D84-9202-4E44410EB249/d/Wrapper/TabView.app' }, proceeding on the assumption it is not translocated: Error Domain=NSPOSIXErrorDomain Code=1 "Operation not permitted” However, the document-based version of TabView also displays these warnings: cannot open file at line 49450 of [1b37c146ee] os_unix.c:49450: (2) open(/private/var/db/DetachedSignatures) - No such file or directory I suspect that the lack of the DetachedSignatures file is the root cause of the ContentView() not being loaded but I cannot find out how to generate a DetachedSignatures file. Adding an empty DetachedSignatures file or directory to /private/var/db/ does not help. Has anyone else experienced this problem (and maybe found a solution)? Should I raise it as a bug via Feedback or am I missing something obvious? Thanks!
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205
Mar ’25
@State memory leak Xcode 16.2
Hi, A class initialized as the initial value of an @State property is not released until the whole View disappears. Every subsequent instance deinitializes properly. Am I missing something, or is this a known issue? struct ContentView: View { // 1 - init first SimpleClass instance @State var simpleClass: SimpleClass? = SimpleClass(name: "First") var body: some View { VStack { Text("Hello, world!") } .task { try? await Task.sleep(for: .seconds(2)) // 2 - init second SimpleClass instance and set as new @State // "First" should deinit simpleClass = SimpleClass(name: "Second") // 3 - "Second" deinit just fine simpleClass = nil } } } class SimpleClass { let name: String init(name: String) { print("init: \(name)") self.name = name } deinit { print("deinit: \(name)") } } output: init: First init: Second deinit: Second Thanks
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287
Feb ’25