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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LongPressGesture.updating(_:body:)
Hello, I'm using LongPressGesture to provide haptic & color change feedback on a long press action. This fails to call the .updating(_:body:) method on every iOS 18.0 beta. It works fine on iOS 17. The following code, taken directly from Apple's documentation illustrates the problem. The .updating() closure is never called, while the .onEnded() closure is called correctly. Instead of a gradual color transition the example code generates a delayed sharp switch from Red to Blue, preventing interactive user feedback. struct LongPressGestureView: View { @GestureState private var isDetectingLongPress = false @State private var completedLongPress = false var longPress: some Gesture { LongPressGesture(minimumDuration: 3) .updating($isDetectingLongPress) { currentState, gestureState, transaction in gestureState = currentState transaction.animation = Animation.easeIn(duration: 2.0) } .onEnded { finished in self.completedLongPress = finished } } var body: some View { Circle() .fill(self.isDetectingLongPress ? Color.red : (self.completedLongPress ? Color.green : Color.blue)) .frame(width: 100, height: 100, alignment: .center) .gesture(longPress) } } Can anyone share tips on a workaround or potential fix application-side?
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1.2k
Feb ’25
Swift charts displaying wrong theme through UIHostingController
Hi there, I'm currently using UIHostingController to display swift charts in uikit. The problem im facing is that the UIHostingController isn't outputting the intended theme. When the simulator/phone is on dark mode the view is still in light mode. Iv'e tried to force the view to use dark mode with: .environment(\.colorScheme, .dark) But it doesn't seem to help. Here's how I implement the UIHostingController to my view: let controller = UIHostingController(rootView: StatVC()) controller.view.translatesAutoresizingMaksIntoConstraints = false addChild(controller) controller.didMove(toParent: self) view.addSubview(controller.view) where StatVC() is the swiftui view which contains the swift chart.
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1.3k
Feb ’25
SwiftUI Popover Crash During Resizing in Stage Manager
SwiftUI Popover Crash on iPad During Resizing in Stage Manager with Exception. *** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Trying to layout popover in the delegate callback popoverPresentationController:willRepositionPopoverToRect:inView: will lead to recursion. Do not force the popover's container view or an ancestor to layout in this callback.' (Occurred from iPadOS 18.1) struct ContentView: View { @State var showPopover: Bool = false var body: some View { VStack { Text("Hello, world!") Button(action: { showPopover = true }, label: { Text("Open Popover") }) } .padding() .popover(isPresented: $showPopover, attachmentAnchor: .point(.trailing), content: { VStack { Text("Popover Content") } }) } }
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Feb ’25
Conflict between offerCodeRedemption and Camera
Hello, I implemented offerCodeRedemption recently on my app in my subscription/onboarding flow. When I did, it broke my camera functionality (elsewhere in the app; totally unrelated code). I was able to fix the issue when implementing the old "AppStore.presentOfferCodeRedeemSheet" code with UIKit. I'm not sure why this is happening, but it seemed like a bug to me.
Topic: UI Frameworks SubTopic: SwiftUI
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Feb ’25
SwiftData on iOS 18 extreme memory use
Hi, I've run into two problems using SwiftData in iOS 18 that are total show-stoppers for my app, causing it to run out of memory and be killed by the system. The same app runs fine on iOS 17. The two problems are inter-related in a way I can't exactly diagnose, but are easy to reproduce. Problem #1: Calling .count on the array that represents a relationship or Query causes the whole array of objects to be loaded into memory. Problem #2: When a @Model object is loaded, properties that are declared with .externalStorage are loaded unnecessarily, and use tons of memory. It's possible that #1 is normal behavior, exacerbated by #2. I've written a test app that demonstrates the extreme difference in memory usage between the OS Versions. It uses a typical navigation pattern, with content counts on the left-side view. Each item has one thumbnail and one large image in .externalStorge. GitHub Source When populated with 80 items, each containing one thumbnail and one large image in .externalStorge, the app launches in 17.5 using 29mb of memory. On iOS 18, in the same conditions, 592 mb. When the first folder is selected, causing a list of thumbnails to load, iOS 17 uses just 86mb. iOS 18 uses 599mb, implying that all image data has already been loaded. So I'm asking for help from Apple or the Community in finding a workaround. I've been advised that finding a workaround may be necessary, as this may not be addressed in 18.0. Thanks in advance for any insight. Radars: FB14323833, FB14323934 (See attached images, or try it yourself) (You may notice in the 18.0 screenshots that the item counts don't add up right. That's yet another 18.0-SwiftData anomaly regarding relationships that I haven't tackled yet, but is also demonstrated by the sample app.)
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Feb ’25
[iOS, SwiftUI] UiRefreshControl.tintColor is not the same as given one
Hello! I'm trying to set a UiRefreshControl.tintColor: .onAppear { UIRefreshControl.appearance().tintColor = UIColor.systemBlue } But instead of I get The color in the second picture is a high contrast version of the first one. I can't understand why it works this way. I also tried the following. UIRefreshControl.appearance().tintColor = UIColor(red: 0, green: 0.478, blue: 1, alpha: 1) // doesn't work UIRefreshControl.appearance().tintColor = UIColor(named: "RefreshControlColor") // doesn't work, here set "High contrast" on and indicated Universal.systemBlueColor Perhaps I missed something?
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Feb ’25
Task cancellation behaviour
Hi everyone, I believe this should be a simple and expected default behavior in a real-world app, but I’m unable to make it work: 1. I have a View (a screen/page in this case) that calls an endpoint using async/await. 2. If the endpoint hasn’t finished, but I navigate forward to a DetailView, I want the endpoint to continue fetching data (i.e., inside the @StateObject ViewModel that the View owns). This way, when I go back, the View will have refreshed with the fetched data once it completes. 3. If the endpoint hasn’t finished and I navigate back to the previous screen, I want it to be canceled, and the @StateObject ViewModel should be deinitialized. I can achieve 1 and 3 using the .task modifier, since it automatically cancels the asynchronous task when the view disappears: view .task { await vm.getData() } I can achieve 1 and 2 using a structured Task in the View (or in the ViewModel, its the same behavior), for example: .onFirstAppearOnly { Task { away vm.getData() } } onFirstAppearOnly is a custom modifier that I have for calling onAppear only once in view lifecycle. Just to clarify, dont think that part is important for the purpose of the example But the question is: How can I achieve all three behaviors? Is this really such an unusual requirement? My minimum deployment target is iOS 15, and I’m using NavigationView + NavigationLink. However, I have also tried using NavigationStack + NavigationPath and still couldn’t get it to work. Any help would be much appreciated. Thank you, folks!
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Feb ’25
How to support foregroundColor (deprecated) and foregroundStyle in watchOS 9/10?
In my Watch app on watchOS 9 I was using .foregroundColor(myColour) to colour the text in a widgetLabel on a corner complication like this: let myColour: Color = functionThatReturnsAColorObjectConstructedLike Color.init(...) // green .widgetLabel { Text(myText) .foregroundColor(myColour) } It worked fine; the widget label was green. Now, in watchOS 10, I see that foregroundColor() is being deprecated in favour of foregroundStyle(), and I can use .foregroundStyle(.green), and - importantly - foregroundStyle() is only available on watchOS 10 and newer. myColour is calculated depending on some other info, so I can't just write .green, and when I use .foregroundStyle(myColour) the widget label comes out as white every time, even if I set myColour = .green. I think I have to use some sort of extension to pick the right combination, something like: extension View { func foregroundType(colour: Colour, style: any ShapeStyle) -> some THING? { if #available(watchOS 10.0, *) { return foregroundStyle(style) } else { return foregroundColor(colour) } } } // Usage let myStyle: any ShapeStyle = SOMETHING? ... .widgetLabel { Text(myText) .foregroundType(colour: myColour, style: myStyle) It doesn't work. I just can't figure out what should be returned, nor how to return it. Any ideas?
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Feb ’25
iOS Architecture Research - Help a student
Hi everyone! I'm thrilled to share that I'm conducting a field research as part of my final university project, focused on iOS architecture. The goal is to dive deeper into the best practices, challenges, and trends in the iOS development world. To make this research truly impactful, I need your help! If you're an iOS developer, I’d love it if you could take a few minutes to answer a short survey. Your insights and experiences will be invaluable for my research, and I greatly appreciate your support! Here is the link: https://docs.google.com/forms/d/e/1FAIpQLSdf9cacfA7my1hnlazyl7uJraa2oTsQ7dJBWvFtZ_4vbYenRA/viewform?usp=send_form Thank you so much in advance for helping me out—feel free to share this post with others who might also be interested. Let’s build something amazing together! 💡✨
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339
Feb ’25
Window color Changed After Exiting Immersive Mode
Create an Empty visionOS App like this. starts in windowed mode, when I enter immersive mode and then exit back to windowed mode, I notice that the window appears dimmer. I start a simple project with settings as image shown below, and took screenShots of my window before and after entering immersive space then quit, compare them, the color value did become dimmer. The issue is reliably repeatable in a given room. If this issue is experienced, adjusting the display brightness to the maximum value and then back to the initial setting will restore the colors to the correct state. Force to exit the app then reopen it can do the same restoration.https://drive.google.com/file/d/1m-a4ghNlSkHhAQuvOCF_IAfcdYeJA14j/view?usp=sharing
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Feb ’25
DatePicker bezel delete?
Is there a SwuiftUI way to remove the bezel from the compact DatePicker on MacOS? I have an AppKit version but getting the font/background colors to behave is overly complicated for such a simple mission.
Topic: UI Frameworks SubTopic: SwiftUI Tags:
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Feb ’25
Note app UI bug
I found a bug in the notes app where if you click on a note the “all iCloud” text will cover over the “all folders” back button and also the “all iCloud” will also hover over the undo button
Topic: UI Frameworks SubTopic: UIKit
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Feb ’25
Suggestion to Add Performance Metrics for SwiftUI in XCTest
As SwiftUI adoption grows, developers face challenges in effectively measuring and optimizing SwiftUI app performance within automated tests. Currently, the only viable approach to analyzing SwiftUI performance is through Profiling (Instruments), which, while powerful, lacks the ability to be incorporated into automated testing workflows. It would be incredibly valuable if XCTest could introduce new performance metrics specifically tailored for SwiftUI, allowing us to write tests against common performance bottlenecks. Suggested Metrics: View Body Evaluation Count – Tracks how often a SwiftUI body is recomputed to detect unnecessary re-renders. Slow View Bodies – Flags SwiftUI views that take a significant amount of time to compute their body. These metrics would help developers identify inefficiencies early, enforce performance best practices through CI/CD pipelines, and ensure a smooth user experience. I believe adding these performance metrics would be a game-changer for SwiftUI development. Thank you for your time and consideration!
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Feb ’25
SwiftUI: toolbar jump weirdly in AppleWatch
Here is the reproducible codes: struct JumpView: View { var body: some View { NavigationStack { TabView { Text("Jump") .toolbar { ToolbarItem(placement: .topBarLeading) { Button("Done") {} } } } } } } Run directly in real apple watch device in watchOS 10.0+ (do not debug connecting with Xcode). When raise your wrist the ToolBar Button will jump weirdly.
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Feb ’25
How to initialize @Observable object in View via @State?
When I switched to observable, I noticed a strange behavior of the ViewModel. The ViewModel is created 3x times. And my question is: How to properly initialize the ViewModel via state? Below is a minimal example with log output: ViewModel INIT : EBBB2C41 ViewModel INIT : D8E490DA ViewModel INIT : 54407300 ViewModel DEINIT: D8E490DA @Observable final class ViewModel { @ObservationIgnored let idd: UUID init() { idd = UUID() print("ViewModel INIT : \(idd.uuidString.prefix(8))") } deinit { print("ViewModel DEINIT: \(idd.uuidString.prefix(8))") } } struct SimpleView: View { @Environment(ViewModel.self) private var viewModel var body: some View { @Bindable var viewModel = viewModel Text("SimpleView: \(viewModel.idd.uuidString.prefix(8))") } } struct ContentView: View { @State private var viewModel = ViewModel() var body: some View { SimpleView() .environment(mainViewModel) } }
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Feb ’25
SwiftUI Table column widths cannot be saved
I have a macOS app made with SwiftUI where I want to show a list of data in a tabular fashion. SwiftUI Table seems to be the only built-in component that can do this. I would like to let the user size the columns and have their widths restored when the app is relaunched. I can find no documentation on how to do this and it does not seem to be saved and restored automatically. I can find no way to listen for changes in the column widths when the user resizes and no way to set the size from code. For a macOS app it seems that the only way to set the width of a column is to use e.g. .width(min: 200, max: 200). This in effect disables resizing of the column. It seems that idealSize is totally ignored on macOS. Any suggestions?
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Feb ’25
Core Data Migration: Custom policy in Entity Mapping for the case where App name contains a space
I am trying to add a custom policy to Entity Mapping and it refuses to work because the app name has a space in it. I tried replacing the space character with underscore and hyphen but it still does not work. I tried creating an MVP where app name did not have any space and it worked in the first try. However, for another MVP where app name had a space in it, it is not working at all.
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Feb ’25
What does the @__EntryDefaultValue macro expand to?
In Xcode 16.0 and 16.1, it was clear how @Entry macro works from the generated code. If you explicitly specify the type, then defaultValue is a computed property, if you do not specify the type, then a stored property. In Xcode 16.2, @__EntryDefaultValue has been added to the generated code, which Xcode does not want to expand. Visually, it seems that a stored property is generated, but the behavior shows that as a result we have a computed property, and for both options: with an explicit type and without an explicit type. So the question is: what does this @__EntryDefaultValue macro generate and is the result a bug? Or was it a bug in previous versions of Xcode?
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Feb ’25
How to return a UIMenu for read-only UITextView
I have a UITextView being added at runtime to a UIImageView as the result of doing text recognition. It's set to be editable = NO and selectable = YES. When I set the text and select it, it asks the delegate for the menu to display via: textView:editMenuForTextInRange:suggestedActions: The suggested items contains many UIAction and UICommand objects that have private methods or do not have the destructive attribute set, yet they are destructive. Some of these are: promptForReplace: transliterateChinese: _insertDrawing: _showTextFormattingOptions: I need to return a menu that has only non-destructive commands in it. First, why isn't UITextView sending only non-destructive suggested commands when its editable is NO? Second, how can I filter the array of suggested commands when it's impossible to know if they're destructive (as some are missing that attribute)? In addition to that, even non-destructive commands are causing an unrecognized selector exception, such as the Speak command, which it is sending to my view controller instead of to the UITextView, which is the only thing that knows what the text is that it should speak.
Topic: UI Frameworks SubTopic: UIKit
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Feb ’25
How Can I Apply A vImage ContrastStretch To A Grayscale Image
I'm writing an app to help with astrophotography, and I need to perform a contrast stretch to the image, because it was taken with a specialized astrophotography camera in monochrome and most of the data is very dark. Most astrophotography software (astropy, Pixinsight) has something called an autostretch, which is a form of contrast stretching. I would like to do the same thing in my iOS app, using the tools available to me in SwiftUI, UIImage, CIImage, and CGImage. I am to the point that I have created a buffer .withUnsafeMutableBufferPointer that contains the image data as 16-bit unsigned integers (the format given to me by the camera). I then create a vImage_Buffer using: var buffer = vImage_Buffer(data: outPtr.baseAddress, height: vImagePixelCount(imageHeight), width: vImagePixelCount(imageWidth), rowBytes: MemoryLayout<Float>.size * imageWidth) ... and now I would like to apply either an equalizeHistogram() or a contrastStretch() to the buffer. What do I need to do? Do I need to create a CGImageFormat, like this? let cgiImageFormat = vImage_CGImageFormat(bitsPerComponent: 16, bitsPerPixel: 16, colorSpace: CGColorSpaceCreateDeviceGray(), bitmapInfo: bitmapInfo)! Which function should I use to do the equalization or contrast stretch? There appears to be a vImageContrastStretch_PlanarF() function, but I'm not sure the input data will be in the proper format (is a monochrome CGImage 32-bit planar F?), and I certainly don't know how to setup the histogram_entries parameter for that function. It seems like the function could just scan the image itself, form the histogram, and then stretch it, right? So a code example would help a lot! Thanks in advance, Robert
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Feb ’25