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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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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400
Mar ’25
`.refreshable(action:)` `s indicator will not dismiss after when app into backgound (iOS 17.1)
Hello, I am encountering an issue with .refreshable(action:) in ScrollView. The refresh action works as expected when performing a pull-to-refresh. However, if I put the app in the background while the refresh operation is in progress, the refresh indicator remains visible on the screen when I return to the foreground and does not disappear. Once I interact with the ScrollView after returning to the foreground, the refresh indicator disappears, and the functionality itself is not affected. I initially attempted to resolve this issue by triggering a view redraw when scenePhase changes. However, since my app presents the SwiftUI view using UIHostingController, the scenePhase from the environment does not seem to function correctly. This issue occurs on iOS 17.1 but does not appear on iOS 16.1.1. Is there a known way to resolve this unexpected behavior? Below is a simplified sample code (some parts are omitted): struct MyView: View { @StateObject private var model: MyModel var body: some View { ScrollView { // My ContentViews... } .refreshable { do { try await self.model.refresh() } catch { // Handle error } } } } @MainActor final class MyModel: ObservableObject { // === Some Code === func refresh() async throws { let data = try await self.fetchData() self.data = Array(OrderedSet(data)) } } I apologize for any mistakes in my English, as I am using a translation tool. Thank you in advance for your help! Best regards,
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208
Mar ’25
How to programmatically set cursor position of a text field in SwiftUI
I would like to understand how to programmatically set the position of a cursor in a SwiftUI TextField. In UIKit this can be done using the selectedTextRange property, but I couldn't find a similar way to achieve this with pure SwiftUI. I want to figure out something like setCursorPosition (index:) - maybe by tracking the position in a @State or any other way. I understand that I can do this using UIViewRepresentable but I am looking for a pure SwiftUI solution and wanted to know if there is any.
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449
Mar ’25
.onTapGesture does not work when SwiftUI component sits in a flipped NSVIew
Take a look at this simple code: import Cocoa import SwiftUI struct DemoView: View { var body: some View { Text("Click me!") .onTapGesture { print("Clicked") } } } class FlippedView: NSView { override var isFlipped: Bool { return true } } class ViewController: NSViewController { override func viewDidLoad() { super.viewDidLoad() let stackView = NSStackView() stackView.orientation = .vertical stackView.alignment = .leading stackView.spacing = 0 stackView.translatesAutoresizingMaskIntoConstraints = false let hostView = NSHostingView(rootView: DemoView()) stackView.addArrangedSubview(hostView) let scrollView = NSScrollView() scrollView.translatesAutoresizingMaskIntoConstraints = false let flippedView = FlippedView() flippedView.addSubview(stackView) scrollView.documentView = flippedView view.addSubview(scrollView) NSLayoutConstraint.activate([ scrollView.topAnchor.constraint(equalTo: view.topAnchor), scrollView.leadingAnchor.constraint(equalTo: view.leadingAnchor), scrollView.trailingAnchor.constraint(equalTo: view.trailingAnchor), scrollView.bottomAnchor.constraint(equalTo: view.bottomAnchor), ]) } } I need my scroll view to start at the very top, so i put it inside a flipped document view. But now .onTapGesture does not fire.
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144
Apr ’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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241
Mar ’25
MapKit causing TabBar Overwrite
Hi everyone! I am having a bit of trouble with why my Map() is overwriting my customized tabBar settings. Specifically my tab bar background. (White -> Black) Map(position: $cameraPosition) { UserAnnotation() } .toolbarBackground(.hidden, for: .tabBar) This above ^ is a view which acts as a tab view for my tab bar. I have customized my tab bar as follows just so it was obvious to see me changes. let tabAppearance = UITabBarAppearance() tabAppearance.configureWithOpaqueBackground() tabAppearance.backgroundColor = .white UITabBar.appearance().standardAppearance = tabAppearance UITabBar.appearance().scrollEdgeAppearance = tabAppearance I have tried implementing solutions which is seen with my .toolbar attempt but nothing has help. I would like the tab bar to be consistent with all of my views and from my understanding the Map is overwriting those settings.
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64
Apr ’25
Unexpected UINavigationController setViewControllers Behavior on iOS 18.2 During Animated Transitions
Hello everyone, I've run into a peculiar behavior with UINavigationController's setViewControllers on iOS 18.2 (I guess it might be reproducible on older versions) when reordering view controllers, and I wonder if anyone can shed some light on this issue. Initial State: The navigation stack is [A - B - C]. Without Animation: Setting [A - C - B] updates the stack to: A - C - B as expected. With Animation: Using the same command with animation changes the stack to [A - B], oddly omitting C. Has anyone else noticed similar behavior or knows why animations might disrupt the stack's update this way? I'd appreciate any insights or suggestions. Thanks, Dmytro
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375
Mar ’25
RePlayKit:screen recording method return sampleBuffer is nil
I want record screen in my app,the method startCaptureWithHandler:completionHandler:,the sampleBuffer, It is supposed to exist but it has become nil.Not only that,but there‘s another problem,when I want to stop recording and save the video,I will check [RPScreenRecorder sharedRecorder].recording first, it will be false sometime,that problems are unusual in iOS 18.3.2 iPhoneXs Max,and unexpected,here is my code -(void)startCaptureScreen { NSLog(@"AKA++ startCaptureScreen"); if ([[RPScreenRecorder sharedRecorder] isRecording]) { return; } //屏幕录制 [[RPScreenRecorder sharedRecorder]setMicrophoneEnabled:YES]; NSLog(@"AKA++ MicrophoneEnabled AAAA startCaptureScreen"); [[RPScreenRecorder sharedRecorder]setCameraEnabled:YES]; [[RPScreenRecorder sharedRecorder] startCaptureWithHandler:^(CMSampleBufferRef _Nonnull sampleBuffer, RPSampleBufferType bufferType, NSError * _Nullable error) { if(self.assetWriter == nil){ if (self.AVAssetWriterStatus == 0) { [self setupAssetWriterAndStartWith:sampleBuffer]; } } if (self.AVAssetWriterStatus != 2) { return; } if (error) { // deal with error return; } if (self.assetWriter.status != AVAssetWriterStatusWriting) { [self assetWriterAppendSampleBufferFailWith:bufferType]; return; } if (bufferType == RPSampleBufferTypeVideo) { if(self.assetWriter.status == 0 ||self.assetWriter.status > 2){ } else if(self.videoAssetWriterInput.readyForMoreMediaData == YES){ BOOL success = [self.videoAssetWriterInput appendSampleBuffer:sampleBuffer]; } } if (bufferType == RPSampleBufferTypeAudioMic) { if(self.assetWriter.status == 0 ||self.assetWriter.status > 2){ } else if(self.audioAssetWriterInput.readyForMoreMediaData == YES){ BOOL success = [self.audioAssetWriterInput appendSampleBuffer:sampleBuffer]; } } } completionHandler:^(NSError * _Nullable error) { //deal with error }]; } and than ,when want to save it : -(void)stopRecording { if([[RPScreenRecorder sharedRecorder] isRecording]){ // The problem is sporadic,recording action failed,it makes me confused } [[RPScreenRecorder sharedRecorder] stopCaptureWithHandler:^(NSError * _Nullable error) { if(!error) { //post message } }]; }
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87
Apr ’25
SWIFTUI: chartLegend alignment 'Centering' option
SWIFTUI : Chart control / view is there way to align the Legends to align the center I see there only 2 options, .chartLegend(position: .bottom, alignment: .leading,spacing: 10) .leading or .trailing code : Chart{ ..... SectorMark.. } .chartLegend(position: .bottom, alignment: .leading,spacing: 10)
Topic: UI Frameworks SubTopic: SwiftUI
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284
Mar ’25
Crash using Binding.init?(_: Binding<Value?>)
In the example code below: OuterView has a @State var number: Int? = 0 InnerView expects a binding of type Int. OuterView uses Binding.init(_: Binding<Value?>) to convert from Binding<Int?> to Binding<Int>?. If OuterView sets number to nil, there is a runtime crash: BindingOperations.ForceUnwrapping.get(base:) + 160 InnerView is being evaluated (executing body?) when number is nil despite the fact that it shouldn't exist in that configuration. Is this a bug or expected behavior? struct OuterView: View { @State var number: Int? = 1 var body: some View { if let binding = Binding($number) { InnerView(number: binding) } Button("Doesn't Crash") { number = 0 } Button("Crashes") { number = nil } } } struct InnerView: View { @Binding var number: Int var body: some View { Text(number.formatted()) } } There is a workaround that involves adding an extension to Optional<Int>: extension Optional<Int> { var nonOptional: Int { get { self ?? 0 } set { self = newValue } } } And using that to ensure that the binding has a some value even when number is nil. if number != nil { InnerView(number: $number.nonOptional) } This works, but I don't understand why it's necessary. Any insight would be greatly appreciated!
Topic: UI Frameworks SubTopic: SwiftUI
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296
Mar ’25
Unexpected onAppear behavior in NavigationStack with ViewThatFits
Hello, My goal is to have a NavigationStack whose root view is determined based on its height and width. To do so, I'm using ViewThatFits, which should choose the right view to display. It is working fine, but unexpectedly both views trigger onAppear, whereas only the appropriate one should. This causes the logic in both closures to be executed, which is not intended. The code below demonstrates the problem: struct NavigationStackContentView: View { var body: some View { NavigationStack { ViewThatFits(in: .vertical) { Color.yellow .onAppear { print("|-> on appear: yellow") } .onDisappear { print("|-> on disappear: yellow") } Color.red .frame(width: 1500, height: 1500) .onAppear { print("|-> on appear: red") } .onDisappear { print("|-> on disappear: red") } } } } } this produces: |-> on appear: red |-> on disappear: red |-> on appear: yellow When ViewThatFits is not nested within NavigationStack, the problem does not occur — only the yellow view (in this sample) triggers onAppear, which is the expected behavior. I also checked the macOS version, and the problem does not occur at all, whether within NavigationStack or not. This example is simple and demonstrates that the larger view is the second one. When I switch their places, the problem does not occur because it recognizes that the first view would not fit at this point. However, in my case I will have these views without knowing which one will not fit, so switching their order is not a viable solution if this works without NavigationStack. Am I doing something wrong, or is this a bug? // iOS: 18.3.1 Xcode: 16.2
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210
Mar ’25
Implement Continuity Markup in Mac app?
Hello, is there a way to implement Continuity Markup in our own apps? (This is what I'm talking about: https://support.apple.com/en-us/102269 , scroll down to "Use Continuity Markup"). Also, why does a QuickLook panel (QLPreviewPanel.shared()) not display the markup options when triggered from my app for png image files in my app's Group Container? Do I need to implement certain NSServicesMenuRequestor methods for that? Sadly, I could not find any docs on that. Thank you, – Matthias
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127
Apr ’25
Crash: KEY_TYPE_OF_DICTIONARY_VIOLATES_HASHABLE_REQUIREMENTS
Hi everyone, frome time to time I see crash which Im not able to debug, because there is no line of my code where crash occured. This is a crash log what Im getting from time to time of some users. In my device I never get this kind of crash. 0 libswiftCore.dylib 0x1172c _assertionFailure(_:_:flags:) + 208 1 libswiftCore.dylib 0x198624 KEY_TYPE_OF_DICTIONARY_VIOLATES_HASHABLE_REQUIREMENTS(_:) + 2980 2 libswiftCore.dylib 0xdb6c8 specialized _NativeDictionary.uncheckedRemove(at:isUnique:) + 534 3 libswiftCore.dylib 0xb250c Dictionary._Variant.setValue(_:forKey:) + 204 4 libswiftCore.dylib 0x5a620 Dictionary.subscript.setter + 520 5 SwiftUICore 0xf62ec ForEachState.item(at:offset:) + 4340 6 SwiftUICore 0xf5054 ForEachState.forEachItem(from:style:do:) + 1796 7 SwiftUICore 0x2272f8 ForEachState.traitKeys.getter + 84 8 SwiftUICore 0x227298 ForEachList.traitKeys.getter + 24 9 SwiftUICore 0x227008 protocol witness for ViewList.traitKeys.getter in conformance SubgraphList + 76 10 SwiftUICore 0x227008 protocol witness for ViewList.traitKeys.getter in conformance SubgraphList + 76 11 SwiftUICore 0x227008 protocol witness for ViewList.traitKeys.getter in conformance SubgraphList + 76 12 SwiftUICore 0x227008 protocol witness for ViewList.traitKeys.getter in conformance SubgraphList + 76 13 SwiftUICore 0x2271fc DynamicViewList.WrappedList.traitKeys.getter + 88 27 SwiftUICore 0x226d18 specialized static SectionAccumulator.processUnsectionedContent(list:contentSubgraph:) + 84 28 SwiftUI 0x26afe0 ListSectionInfo.init(list:listAttribute:contentSubgraph:) + 132 29 SwiftUI 0x269bb0 UpdateCollectionViewListCoordinator.updateValue() + 1528 30 SwiftUI 0x785d4 partial apply for implicit closure #1 in closure #1 in closure #1 in Attribute.init<A>(_:) + 32 31 AttributeGraph 0xccac AG::Graph::UpdateStack::update() + 540 32 AttributeGraph 0xc870 AG::Graph::update_attribute(AG::data::ptr<AG::Node>, unsigned int) + 424 33 AttributeGraph 0xc444 AG::Subgraph::update(unsigned int) + 848 34 SwiftUICore 0x805a8 GraphHost.flushTransactions() + 860 35 SwiftUI 0x1ac84 closure #1 in _UIHostingView._renderForTest(interval:) + 24 36 SwiftUICore 0x7ffa8 partial apply for closure #1 in ViewGraphDelegate.updateGraph<A>(body:) + 28 37 SwiftUICore 0x7fd6c ViewRendererHost.updateViewGraph<A>(body:) + 120 38 SwiftUICore 0x7fce8 ViewGraphDelegate.updateGraph<A>(body:) + 84 39 SwiftUI 0x3e688 closure #1 in closure #1 in closure #1 in _UIHostingView.beginTransaction() + 172 40 SwiftUI 0x3e5d4 partial apply for closure #1 in closure #1 in closure #1 in _UIHostingView.beginTransaction() + 24 41 SwiftUICore 0x79720 closure #1 in static Update.ensure<A>(_:) + 56 42 SwiftUICore 0x796a4 static Update.ensure<A>(_:) + 100 43 SwiftUI 0x9c808 partial apply for closure #1 in closure #1 in _UIHostingView.beginTransaction() + 80 44 SwiftUICore 0x7f5e0 thunk for @callee_guaranteed () -> () + 28 45 SwiftUICore 0x6161c specialized closure #1 in static NSRunLoop.addObserver(_:) + 144 46 CoreFoundation 0x218a4 __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 36 47 CoreFoundation 0x213f8 __CFRunLoopDoObservers + 552 48 CoreFoundation 0x75da8 __CFRunLoopRun + 948 49 CoreFoundation 0xc8284 CFRunLoopRunSpecific + 588 50 GraphicsServices 0x14c0 GSEventRunModal + 164 51 UIKitCore 0x3ee674 -[UIApplication _run] + 816 52 UIKitCore 0x14e88 UIApplicationMain + 340 53 SwiftUI 0x291ef8 closure #1 in KitRendererCommon(_:) + 168 54 SwiftUI 0x291e28 runApp<A>(_:) + 100 55 SwiftUI 0x291d0c static App.main() + 180 56 DholRainbow 0x3019e8 main + 4339145192 (DholRainbowApp.swift:4339145192) 57 ??? 0x1b0bf5de8 (Missing) From Crashlytics I know at least human readable format of this error Fatal error: Duplicate keys of type 'Contact' were found in a Dictionary. This usually means either that the type violates Hashable's requirements, or that members of such a dictionary were mutated after insertion. I 've checked all my parts of code where Im using dictionary. This is a function which creating that particulary dictionary. private func logsByDate() { let groupedByDate = Dictionary(grouping: logs.filter { ($0.remoteParty as? Contact != nil) } ) { $0.date.removeTimeStamp ?? .distantPast }.mapValues { $0.compactMap { $0 } } var dayLogs = [DayLog]() for date in groupedByDate { var contacts = [CallLogContact]() for log in logs.filter({ $0.date.removeTimeStamp ?? .distantPast == date.key }) { if let contact = log.remoteParty as? Contact { if contacts.firstIndex(where: {$0.contact == contact }) == nil { let contactDayLogs = logs.filter({ $0.remoteParty as? Contact == contact && $0.date.removeTimeStamp == date.key}) contacts.append( CallLogContact( contact: contact, logs: contactDayLogs, lastCallLogDate: contactDayLogs.sorted(by: {$0.date > $1.date}).first?.date ?? .distantPast ) ) } } } dayLogs.append(DayLog(date: date.key, contact: contacts)) } DispatchQueue.main.async { self.groupedCallLogs = dayLogs } } This function is called from 3 others functions based on notification from the server in case of new call log, fetched call logs and removed call logs.
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294
Mar ’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?
6
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238
Apr ’25
Mixing NavigationLink types (value: and non-value: types)
Hello, I was wondering if someone could clear-up my thinking here. e.g. consider the code below... It has a rootView with a navlink to a childView which in turn has navlinks to GrandchildViews. The root view uses basic navLInks NavigationLink{View} label: {View} The child view uses type-based navLinks navigationLink(value:) {View} and .navigationDestination(for:) {View} I would expect the basic navlinks to work in the root view and the type-based ones to work in the child view. However it appears that both are active when one taps on a link in the child view. e.g. User actions: Start -> RootView is only view on the stack -> (tap on ‘Child View’) -> ChildView is top of the stack -> tap on ‘Alice’ -> a second ChildView is top of the stack with a GrandchildView underneath…. Why does this happen, why are the basic links also applied to the childView's links? Thanks. struct Thing: Identifiable, Hashable { let id = UUID() let name: String } struct RootView: View { var body: some View { NavigationStack { List { NavigationLink { ChildView() } label: { Label("Child View", systemImage: "figure.and.child.holdinghands") } NavigationLink { Text("Hello") } label: { Label("Another navLink item in the list", systemImage: "circle") } } .padding() } } } struct ChildView: View { private var things = [ Thing(name: "Alice"), Thing(name: "Bob"), Thing(name: "Charlie"), ] var body: some View { Text("This is the child view") List { ForEach(things) { thing in NavigationLink(value: thing) { Text(thing.name) } } } .navigationTitle("Child View") .navigationDestination(for: Thing.self) { thing in GrandchildView(thing: thing) } } } struct GrandchildView: View { let thing: Thing var body: some View { Text("This is the GrandchildView: \(thing.name)") } }
Topic: UI Frameworks SubTopic: SwiftUI
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132
Mar ’25
How do we pass a selected item to a sheet?
I have view showing a list of contacts. When the user taps one, I want to raise a sheet that shows the contact's phone numbers and E-mail addresses and lets the user pick one. When the user taps a list entry, I store the associated Contact object into a @State variable called selectedContact. Then I set the boolean that's bound to the sheet modifier's isPresented flag. That modifier: .sheet(isPresented: $showContactMethodSheet, content: { ContactMethodView(withContact: selectedContact!) }) But the app crashes, because despite selectedContact having been set. It looks like the sheet was pre-built with a nil selected contact upon view load. Why, and what is the expected approach here?
Topic: UI Frameworks SubTopic: SwiftUI
3
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248
Mar ’25
Picker with inline style on tvOS 18
Since tvOS 18, my Picker view with inline style is not showing the checkmark on the selected item. enum Flavor: String, Identifiable { case chocolate, vanilla, strawberry var id: Self { self } } struct ContentView: View { @State private var selectedFlavor: Flavor = .chocolate var body: some View { NavigationView { Form { Picker("Flavor", selection: $selectedFlavor) { Text("Chocolate").tag(Flavor.chocolate) Text("Vanilla").tag(Flavor.vanilla) Text("Strawberry").tag(Flavor.strawberry) }.pickerStyle(.inline) } } } } Am I missing something? When I run this on tvOS 17.x, it works fine.
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94
Mar ’25