Provide views, controls, and layout structures for declaring your app's user interface using SwiftUI.

SwiftUI Documentation

Post

Replies

Boosts

Views

Activity

@Environment(\.dismiss) var dismiss - Infinite loop bug.
The following code works: struct SelectBatteryChemistryView: View {     @ObservedObject var model: SelectBatteryChemistryViewModel = .init()     @Environment(\.presentationMode) private var presentationMode     var body: some View {         VStack {             Spacer()             TitleText("BATTERY MODE")             SimpleModeSelectorView(                 selected: $model.batteryChemistry             )             .pickerStyle(.inline)             .frame(minHeight: 300)             PrimaryTitleButton(title: "SELECT") {                 if model.batteryChemistry == .user {                     model.customChemistryFlow = true                 } else {                     model.confirmBatterySettings()                 }             }             NavigationLink(                 destination: CustomBatteryChemistryView(),                 isActive: $model.customChemistryFlow             ) { EmptyView() }                 .isDetailLink(false)         }         .onReceive(model.$batterySettingsConfirmed) { batterySettingsConfirmed in             if batterySettingsConfirmed {                 //dismiss()             }         }         .onAppear() {             model.customChemistryFlow = false         }     } } The following code causes an infinite loop in the CustomBatteryChemistryView() initialiser. struct SelectBatteryChemistryView: View {     @ObservedObject var model: SelectBatteryChemistryViewModel = .init()     @Environment(\.dismiss) private var dismiss     var body: some View {         VStack {             Spacer()             TitleText("BATTERY MODE")             SimpleModeSelectorView(                 selected: $model.batteryChemistry             )             .pickerStyle(.inline)             .frame(minHeight: 300)             PrimaryTitleButton(title: "SELECT") {                 if model.batteryChemistry == .user {                     model.customChemistryFlow = true                 } else {                     model.confirmBatterySettings()                 }             }             NavigationLink(                 destination: CustomBatteryChemistryView(),                 isActive: $model.customChemistryFlow             ) { EmptyView() }                 .isDetailLink(false)         }         .onReceive(model.$batterySettingsConfirmed) { batterySettingsConfirmed in             if batterySettingsConfirmed {                 //dismiss()             }         }         .onAppear() {             model.customChemistryFlow = false         }     } } Adding the @Environment(.dismiss) object prevents the use of a navigation link. The program sits there with the stack infinitely calling the getter for the NavigationLink. It looks like an infinite loop on the accessor due to some strangeness related to the magic of the Dismiss environment object. How do we pass this on to the Dev team at Apple?
9
7
2.7k
Nov ’22
Print a SwiftUI view on macOS?
I made a test with a new XIB-based project using this code     func applicationDidFinishLaunching(_ aNotification: Notification) {         guard let content = window.contentView else {             print("Error: cannot access windows contentview!")             return         }                  let tv = NSTextView(frame: NSMakeRect(100, 300, 200, 40))         tv.string = "Text subview"         tv.font = NSFont.systemFont(ofSize: 30.0)         content.addSubview(tv)         let chartView = NSHostingView(rootView: myChart())         chartView.setFrameSize(content.frame.size)         content.addSubview(chartView)         content.printView(self)             } "myChart" is s sample view using Charts. The window does show the text and the chart but the print shows the text only. How can I get the SwiftUI-View printed? My goal is a PDF output of a SwiftUI view. There are already several older threads with similar questions but no solution, yet.
2
0
708
Dec ’22
NavigationStack inside NavigationSplitView on Mac
I've seen several posts regarding NavigationStack in a NavigationSplitView. All had specific issues and some were marked as resolved. I couldn't get any of the suggested solutions working on macOS so I'll present some stripped down examples, all part of FB11842563: 1. Sidebar Selection struct SidebarSelection: View {     @State var selection: Int?     @State var path: [Int] = []     var body: some View {         NavigationSplitView {             List(1...20, id: \.self, selection: $selection) { number in                     Text("I like \(number)")             }         } detail: {             NavigationStack(path: $path) {                 VStack {                     Image(systemName: "x.squareroot")                         .imageScale(.large)                         .foregroundColor(.accentColor)                     Text("This is the NavigationStack root")                 }                 .padding()                 .navigationDestination(for: Int.self) { number in                     Text("You chose \(number)")                 }             }         }         .onChange(of: selection) { newValue in             print("You clicked \(newValue)")             if let newValue {                 path.append(newValue)             }         }         .onChange(of: path) { newValue in             print("Path changed to \(path)")         }     } } If we run this and click: „I like 5“ „I like 6“ „I like 7“ We would expect the detail view to show: „You chose 5“ „You chose 6“ „You chose 7“ And the console to show: You clicked Optional(5) Path changed to [5] You clicked Optional(6) Path changed to [5, 6] You clicked Optional(7) Path changed to [5, 6, 7] What we actually see in the detail view is: „You chose 5“ „This is the NavigationStack root“ „You chose 7“ And the console shows: Update NavigationRequestObserver tried to update multiple times per frame. You clicked Optional(5) Path changed to [5] You clicked Optional(6) Path changed to [] You clicked Optional(7) Path changed to [7] 2. Sidebar and Stack Selection Now we copy the list to the navigationDestination: struct SidebarAndStackSelection: View {     @State var selection: Int?     @State var path: [Int] = []     var body: some View {         NavigationSplitView {             List(1...20, id: \.self, selection: $selection) { number in                     Text("I like \(number)")             }         } detail: {             NavigationStack(path: $path) {                 VStack {                     Image(systemName: "x.squareroot")                         .imageScale(.large)                         .foregroundColor(.accentColor)                     Text("This is the NavigationStack root")                 }                 .padding()                 .navigationDestination(for: Int.self) { number in                     VStack {                         Text("You chose \(number)")                         List(1...20, id: \.self, selection: $selection) { number in                             Text("I like \(number)")                         }                     }                 }             }         }         .onChange(of: selection) { newValue in             print("You clicked \(newValue)")             if let newValue {                 path.append(newValue)             }         }         .onChange(of: path) { newValue in             print("Path changed to \(path)")         }     } } We repeat our test from above, clicking either on the sidebar or in the detail view and we expect the same outcome. This time the detail view shows the expected screen and the path is not completely wiped out but it is also not appended: Update NavigationRequestObserver tried to update multiple times per frame. You clicked Optional(5) Path changed to [5] You clicked Optional(6) Path changed to [6] You clicked Optional(7) Path changed to [7] 3. Sidebar and Stack Selection, initialized Same as before, but now we initialize the view with a non-empty path: SidebarAndStackSelection(path: [1]) The app freezes on launch, CPU is at 100 percent and the console shows only: Update NavigationRequestObserver tried to update multiple times per frame. Update NavigationRequestObserver tried to update multiple times per frame. The SwiftUI instruments seem to show heavy activity of the Stack and the SplitView: 4. Selection only in Stack Once we remove the selection from the sidebar everything works as expected (adding the NavigationStack to the root view to be able to click on a number): struct SidebarWithoutSelectionButStack: View {          @State var selection: Int?     @State var path: [Int] = []          var body: some View {         NavigationSplitView {             List(1...20, id: \.self) { number in                     Text("I like \(number)")             }         } detail: {             NavigationStack(path: $path) {                 List(1...20, id: \.self, selection: $selection) { number in                     Text("I like \(number)")                 }                 .padding()                 .navigationDestination(for: Int.self) { number in                     VStack {                         Text("You chose \(number)")                         List(1...20, id: \.self, selection: $selection) { number in                             Text("I like \(number)")                         }                     }                 }             }         }         .onChange(of: selection) { newValue in             print("You clicked \(newValue)")             if let newValue {                 path.append(newValue)             }         }         .onChange(of: path) { newValue in             print("Path changed to \(path)")         }     } } Problem of course is, that now the sidebar is useless.
6
2
1.6k
Dec ’22
SwiftU keyboard toolbar disappearing after present additional .sheet
I added a keyboard toolbar inside ZStack. And it works right after appears as expected But after opening and closing another view over the .sheet modifier, The keyboard toolbar doesn't show anymore. ZStack { . .. TextField() .toolbar { ToolbarItemGroup(placement: .keyboard) { .... } } } .sheet(isPresent: $binding) { Some other view } Seems it happened after upgrading to iOS 16. Does anybody has the solution? Thanks
8
5
3.3k
Dec ’22
Localization settings hidden if only 1 preffered language in iOS
I have added additional localizations into my iOS app. iOS is not available in those languages. So I did as it is suggested that you redirect customers to app settings view UIApplication.openSettingsURLString and there they can select another app language. Unfortunately they do not see language selection if they do not have set at least 2 Preferred languages in General -> Languages & Region. Also it does not matter what languages they have there. If my app does not support those then it still shows all localizations available. Is there somehow to force it? So it would be visible always? Since most people in my country have iPhones only in English but would like to use Apps in their native language.. Since they do not have 2 preferred languages they cant see the selection :(
7
7
3.8k
Dec ’22
Having Trouble passing a ButtonStyle as a parameter to a func
I have a SwiftUI View where the body looks like this              VStack {                   VStack(spacing: 4) {                     Text("Outline")                     Button("Tap Me") {                       print("tapped")                     }                     .buttonStyle(.outline)                   }                   VStack(spacing: 4) {                     Text("Simple")                     Button("Tap Me") {                       print("tapped")                     }                     .buttonStyle(.simple)                   }                 } So to remove the duplication, I want to do something like this:      func textButton(title: String, buttonStyle: ButtonStyle) -> some View {       VStack {         Text(title)         Button("hello") {           print("tapped")         }           .buttonStyle(buttonStyle)       }     } The compiler asks me to add 'any' before ButtonStyle. When I do that I get the following: "Type 'any View' cannot conform to 'View'" It works fine if I don't pass in the ButtonStyle. Any suggestions on how to pass a ButtonStyle into a func? thanks, in advance!
2
1
1.9k
Dec ’22
Its time for SwiftUI on the web! (WASM, WEBGL)
Hello Apple Community, With a backend development background, I was always reluctant to do any front end. Especially with my bad experience with html & css, my negative opinion towards UI only got stronger. When starting a new project at my current company, I was forced to do SwiftUI for iOS. After a few small (I mean really small) hiccups, I really understood the concept and it all became natural. This positive experience made me want to try other front end frameworks which work for web. I dipped my toes into Jetpack Compose, C# UWP/WPF, Rust with EGUI. I was really impressed with the performance and possibilities of Rust (EGUI) compiled to WASM. I was especially impressed that you do not have to use any HTML or CSS rather the rendering is completely up to you just like with a desktop application. I was always disappointed of the necessity of html, but with the rise of WASM in the recent years, I really hope there will be amazing alternatives using WASM & WEBGL. Rust with EGUI is good and all but lets be honest to our self: With the ease of SwiftUI, its obvious why all the best looking applications are on iOS. Its time for SwiftUI in web. The advantages for the developers are obvious: Arguably better UI Framework No Html DOM stuff Friendlier for new developers One framework & language for multiple platforms etc ... But whats in for Apple? Why "waste" resources? In my opinion the most important thing is: Increased Developer adoption What is your opinion on this topic? Would you use SwiftUI for web? What are you currently using for web? Do you prefer any other frontend framework over SwiftUI? (not considering the platform)
3
8
2.2k
Dec ’22
Animation on list not working on NavigationSplitView's `Sidebar`
Here are the sample codes: import SwiftUI struct Item: Identifiable, Hashable { var id = UUID() var text: String } struct Player: Identifiable { var id = UUID() var score: String } struct TestView: View { @State var sidebarItems: [Item] = [ .init(text: "1"), .init(text: "2") ] @State var players: [Player] = [ .init(score: "2"), .init(score: "3"), .init(score: "6"), .init(score: "1")] @State private var selectedItem: Item? var body: some View { NavigationSplitView(columnVisibility: .constant(.all)) { List(sidebarItems, selection: $selectedItem) { item in Text(item.text) } Button("shuffle") { withAnimation(.easeIn) { players.shuffle() sidebarItems.shuffle() } } } content: { List { ForEach(players) { player in Text(player.score) } } } detail: { Text("Detail") } } } struct TestView_Previews: PreviewProvider { static var previews: some View { TestView() } } But as a result. Animation working fine on content but not on sidebar
2
1
638
Dec ’22
SwiftUI StateObject crash: “failed to demangle witness for associated type 'Property’”
Hello, we have weird crash in our app that mostly seems to happen right after launch. It is quite rare and so far I haven’t been able to reproduce it (the info below comes from Crashlytics). The main error message I have is this: failed to demangle witness for associated type 'Property' in conformance 'SwiftUI.StateObject<AppBlock.QuickBlockActivityViewModel>.(unknown context at $18f34e5b8).Box: DynamicPropertyBox' from mangled name ' � ��yxG' - subject type x does not conform to protocol ObservableObject And here is the stack trace: Crashed: com.apple.main-thread 0 libsystem_kernel.dylib 0x7200 __pthread_kill + 8 1 libsystem_pthread.dylib 0x71ac pthread_kill + 268 2 libsystem_c.dylib 0x20ca0 abort + 180 3 libswiftCore.dylib 0x3d7304 swift::fatalError(unsigned int, char const*, ...) + 134 4 libswiftCore.dylib 0x3d7324 swift::warningv(unsigned int, char const*, char*) + 30 5 libswiftCore.dylib 0x3ee678 swift_getAssociatedConformanceWitnessSlowImpl(swift::TargetWitnessTable<swift::InProcess>*, swift::TargetMetadata<swift::InProcess> const*, swift::TargetMetadata<swift::InProcess> const*, swift::TargetProtocolRequirement<swift::InProcess> const*, swift::TargetProtocolRequirement<swift::InProcess> const*) + 2078 6 libswiftCore.dylib 0x3ecb9c swift_getAssociatedTypeWitness + 236 7 SwiftUI 0x5b838 OUTLINED_FUNCTION_49 + 640 8 SwiftUI 0xa8d68 OUTLINED_FUNCTION_513 + 16260 9 SwiftUI 0x58244 OUTLINED_FUNCTION_177 + 10892 10 SwiftUI 0x95524 OUTLINED_FUNCTION_1160 + 6632 We are using the view model (QuickBlockActivityViewModel) in a SwiftUI view that is part of collection view using the new UIHostingConfiguration from iOS 16. Our view model is a subclass of view model for older iOS versions that conforms to ObservableObject and is marked as @MainActor. And the view model is used like this: @StateObject private var viewModel = QuickBlockActivityViewModel() Internally the view model uses Combine to monitor a couple of states from other parts of the app to modify its properties.
5
2
2.0k
Jan ’23
iOS SwiftUI WidgetKit: My widgets don’t show up in the ‘Add Widgets’ section
I developed an app with 10 widgets but some iPhone, iPad or macOS users report that my widgets or the "App Name" don't appear in the widgets list when they tried to add the widgets of my app. There's no way I can replicate the problem, but the number of the users that report this issue is growing up every day. It’s not clear if the problem is caused by the iPhone model, a crash on the widget preview or other factors. My widgets previews are built reading static data, so this data is the same in every conditions. I suggest my users to do the following steps: Start the app and go to check again if "App name" appears among widget List Close every app and restart the device; then start the app and go to check again if "App name" appears among widget List Temporarily change system language and turn on Bold Text and go to check again if "App Name" appears among widget List Uninstall and reinstall the app, start the app and go to check again if "App Name" appears among widget List But all users who have tried these steps say that the app still does not appear in the list of widgets. The following code is the one I use inside the main widgets swift file called TodayWidgetExtension: import WidgetKit import SwiftUI struct PlaceholderView : View { var body: some View { Text("loading") } } //MARK: - Main widget bundle configuration @main struct WidgetBundle: WidgetBundle { @WidgetBundleBuilder var body: some Widget { //MARK: - 1 Widget1Large() Widget1Medium() Widget1Small() if #available(iOSApplicationExtension 16.0, *) { Widget1Accessory() } //MARK: - 2 Widget2Large() //MARK: - 3 #if !targetEnvironment(macCatalyst) Widget3Medium() #endif //MARK: - 4 Widget4Large() //MARK: - 5 Widget5Medium() //MARK: - 6 Widget6Large() Widget6Medium() } } struct todaywidgetextension_Previews: PreviewProvider { static var previews: some View { PlaceholderView() .previewContext(WidgetPreviewContext(family: .systemSmall)) } } The only thing that I've noticed debugging the widgets extension is that, even if I don't add any of them to my iPhone screen, Xcode tells me that widgets occupied 20mb of memory (the limit for widgets is 30mb). I tried removing all the widgets from the above code leaving only one (Widget1Small for example), but Xcode continues to tell me that 20mb of memory are still occupied. I hope that someone can help me. Thank you.
1
0
742
Jan ’23
Text view with .timer style expands too much in Live Activity
I'm implementing a Timer in my app and I want the countdown to show up as a Live Activity. It works, but I get a very weird expanding effect on the Text view. The screenshots below show the issue, I can't tell if it's a bug or if I'm doing something wrong. My goal is to shrink the live activity black area so that it's a smaller, more reasonable size. There's no reason for it to be as large as it is on the trailing side. The Live Activity code (very basic):   } dynamicIsland: { context in        } compactTrailing: { // Important bit is here            Text(Date(), style: .timer)        }    } Which renders like this, with a lot of space after the timer: Adding a background color shows the view is expanding: Text(Date(), style: .timer)     .background(.red) And if I replace the timer with a standard text view, then no issue: Text("Hello")        .background(.red) Getting out of live activities and showing a standard timer view, there is no expansion issue: struct TestView: View {     var body: some View {         Text(Date(), style: .timer)             .background(.red)     } } So... I'm stumped. Any advice is appreciated.
6
8
2.9k
Jan ’23
Hand tracking to fbx
i saw there is a way to track hands with vision, but is there also a way to record that movement and export it to fbx? Oh and is there a way to set only one hand to be recorded or both at the same time? Implementation will be in SwiftUI
1
0
1.1k
Jan ’23
SwiftUI Navigation Bar appears behind Status Bar
We have a NavigationView embedded within a TabView, like this: TabView(selection: $tabSelection) { NavigationView { When a view gets pushed onto the stack in the NavigationView, the NavigationBar appears too high, almost under the StatusBar, as shown in the attached picture. If you touch the StatusBar, somehow it alerts the NavigationBar to scoot downward into its correct position. I discovered a hack where I quickly toggle the StatusBar off, then back on, which accomplishes the same thing. My question, though, is why is this necessary? Why isn't the NavigationBar in the correct place to begin with? Here's the hack that fixes it: .onAppear { withAnimation(.linear(duration: 0.3)) { appViewModel.hideStatusBar.toggle() } DispatchQueue.main.asyncAfter(deadline: .now() + 0.3) { withAnimation(.easeInOut(duration: 0.3)) { appViewModel.hideStatusBar.toggle() } } }
2
0
893
Jan ’23
SwiftUI app crashes while scrolling section in List via ScrollViewReader
In our SwiftUI application , we are using List in one of our screen. We have a requirement to scroll to specific section header. Below code works fine till iOS16 and from iOS16 onwards we are getting the app crash. Can anyone suggest me any probable solution to achive this ?.         ScrollViewReader { proxy in             List {                 ForEach(Array(viewModel.newSections), id: .self) { sectionName in                     Section(header: VStack { LeaguesScheduleListSectionView(text: sectionName) }) {                         ForEach(viewModel.newRowsPerSection[sectionName] ?? []) { leagueScheduleEvent in                             LeaguesScheduleListRowView(leagueSchedule: leagueScheduleEvent)                         }                     }                     .id(sectionName)                 }             }             .listStyle(.plain)             .onAppear(perform: {                  if viewModel.newSections.contains("Today/Ongoing"),                  viewModel.newRowsPerSection[("Today/Ongoing")]?.count ?? 0 > 0 {                  proxy.scrollTo("Today/Ongoing", anchor: UnitPoint.topLeading)                  }             })         }
2
0
949
Mar ’23
SwiftUI’s LongPressGesture is broken
Problem LongPressGesture ignores minimumDuration parameter and succeeds immediately, also onEnded is never invoked. Steps to reproduce Take Apple’s own sample code from their documentation: LongPressGesture. Remove transaction.animation = Animation.easeIn(duration: 2.0) line to make the effect more obvious. Expected result: The circle must turn red after 3 seconds of pressing on it, and turn green when released. Actual result The circle turns red immediately and never turns green. Notes I tried many combinations of .gesture and .simultaneousGesture applied to different types of views. Was anyone able to make the minimum duration work when passed to .gesture modifier?
3
4
825
Mar ’23
Picker selection not changing
Hello, I have made a picker that is filled with data from an API endpoint. The data is retrieved and shown properly, however, when trying to change the selection on the picker, it does not work. For simple demonstration i have put the picker in a empty view. Here is the code: import SwiftUI struct TestView: View { struct Subject: Hashable { let subjectId: Int let subjectName: String } @State var subjects: [Subject] = [] @State var selectedSubject: Subject? = nil var body: some View { VStack { Picker(selection: $selectedSubject, label: Text("Kies een vak")) { ForEach(subjects, id: \.self) { subject in Text(subject.subjectName).tag(subject) } } .frame(width: 300, height: 50) .background(Color.black.opacity(0.05)) .cornerRadius(10) .onChange(of: selectedSubject) { newSubject in print("Chosen subject: \(newSubject?.subjectId ?? -1)") } Text("Chosen subject: \(selectedSubject?.subjectId ?? -1)") } .onAppear { Api().extractSubjects { subjects in DispatchQueue.main.async { self.subjects = subjects.map { TestView.Subject(subjectId: $0.subjectId, subjectName: $0.subjectName) } } } } } } To better illustrate what I mean i have made a screenrecording: I hope you guys and girls can help me out. If you need more info, please let me know! Any help or suggestion is greatly appreciated, thanks!
2
0
1.8k
Mar ’23
NO ANIMATIONS in NavigationStack or NavigationSplitView
I'm building a macOS app using SwiftUI and I recently updated to xcode 14.3. Since then I've been debugging why none of my animations were working, it turned out that the NavigationSplitView or NavigationStack are somehow interfering with all the animations from withAnimation to .transition() and everything in between. Is anyone else experiencing this, knows a work around or knows why this is happening?
11
9
7.1k
Apr ’23
Why isn't the View protocol @MainActor?
Hi, It is known that if a SwiftUI view contains an @ObservedObject or @StateObject property, the View will inherit @MainActor isolation from the property wrappers. Similarly, the body view-builder is also marked @MainActor. What I'm wondering is why the whole SwiftUI View protocol isn't marked @MainActor. It seems to be a deliberate decision, but AFAICT it would make a lot of sense for all data and operations defined in a view to have main-actor isolation unless marked nonisolated. I'm currently adding @MainActor annotations to an existing codebase, and it's a bit awkward that some views automatically gain this attribute one way or another, while others need it explicitly applied. Is there a rationale that can be shared, or is this something which may be revised in future versions of the framework?
1
6
1.7k
May ’23