Discuss the different user interface frameworks available for your app.

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Severe Scroll Lag & Header Flickering in Complex SwiftUI Screen with Dynamic Content (GeometryReader + Scroll Direction Detection)
I’m working on a SwiftUI screen where I need to hide a header when the user scrolls down and show it again when the user scrolls up. I’m currently using a ScrollView combined with GeometryReader to detect scroll offset changes and update state variables like isScrolling or isScrollingDown. The issue is that the behavior is inconsistent. When I scroll down, the header hides correctly, but when I scroll back up, the header often doesn’t appear again even though the offset is changing. Sometimes the header comes back with a delay, and other times it never appears at all. Along with this, I’m also seeing noticeable UI lag whenever I try to calculate content height or read multiple geometry values inside the ScrollView. It looks like the frequent state updates inside the scroll offset tracking are causing layout recalculations and frame drops. I’ve tried placing the header in different positions (inside a ZStack aligned to the top, inside the VStack above the ScrollView, and with transitions like .push(from: .top)), but the result is still the same: smooth scrolling breaks, and the header doesn’t reliably animate back when scrolling upward. What I’m looking for is a minimal and efficient approach to detect scroll direction and trigger the header hide/show animation without causing performance issues or recomputing expensive layout values. Any guidance or a simplified pattern that works well for dynamic headers in SwiftUI would be very helpful. if isScrolling { headerStackView() //Includes Navigation Bar .transition( .asymmetric( insertion: .push(from: .top), removal: .push(from: .bottom) ) ) } GeometryReader { outer in let outerHeight = outer.size.height ScrollView(.vertical) { VStack { content() // Heavy view + contains its own ScrollView } .background { GeometryReader { proxy in let contentHeight = proxy.size.height let minY = max( min(0, proxy.frame(in: .named("ScrollView")).minY), outerHeight - contentHeight ) if #available(iOS 17.0, *) { Color.clear .onChange(of: minY) { oldVal, newVal in // Scroll direction detection if (isScrolling && newVal < oldVal) || (!isScrolling && newVal > oldVal) { isScrolling = newVal > oldVal } } } } } } .coordinateSpace(name: "ScrollView") } .padding(.top, 1)
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Nov ’25
Unable to Display NSProgressIndicator on macOS Unlock (First Lock) Screen
I'm Trying to add an NSProgressIndicator on the unlock (first lock screen ) in macOS ( the screen with the lock icon ) I already added a label and it works fine and after entering the password on the second (authentication) page I can able to add ProgressIndicator but not on first screen. But Whenever I try to add a Progress indicator, the entire screen turns Black and nothing is displayed Is NSProgressIndicator supported on the first unlock Screen ? Or does macOS block animated UI on this screen Any Guidance would be helpful Thanks
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Nov ’25
UIKit flip animation bugged in 26.1
Hello. I have an 12 year old app that still has some objective-c code in it. I have a place where i have a flip animation between 2 view controllers that looks like this: [UIView transitionFromView:origView toView:newViewController.view duration:0.5 options:UIViewAnimationOptionTransitionFlipFromRight completion:nil]; It has looked like this since 2012 at least. In our production release, it works prior to 26.1, but in 26.1 and 26.2, the flip is off-center and looks weird. it's like both edges flip the same way. It's a little bit hard to explain. If seen at least 2 other app store apps that i have installed behave this way too, from 26.1 and onwards. Anyone else seen this? Is there anything that can be done about it? Thankful for thoughts.
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Nov ’25
Paste button on navigation bar is not shown on iOS/iPadOS 26
The Paste button (using UIPasteControll) located on UINavigationBar is not shown at application startup on iOS/iPadOS 26. This issue will disappear when device is rotated or window size is changed. And this issue does not occur on iOS / iPadOS 18 and earlier. I uploaded the sample project to github at the following URL. https://github.com/gpn-galapagos/PasteButtonApp.git Has anyone had the same issue or knows a workaround?
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191
Dec ’25
NSButtons disappear on macOS 26
I have attached 2 images of our Mac Apps user interface. The app is built for macOS 15.6 or newer. On macOS 15 and earlier everything looks fine. But the same App running on macOS 26 the controls disappear. We were able to temporarily resolve the problem by adding UIDesignRequiresCompatibility to the info.plist. This type of nonsense happens all over the app without the compatibility switch. Shouldn't all these legacy controls be backward compatible on Glass? This part of the app where the controls are disappearing is built in Swift (not swift ui) and uses standard programatic layout and visual constraints. On macOS 26, there are no Xcode warnings or layout errors on the console relative to the layout so we are confused as to how we would resolve this without the use of UIDesignRequiresCompatibility. Is this some kind of bug in NSControl glass compatibility? We are not likely to move the entire app into SwiftUI anytime soon. How would we resolve this?
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Dec ’25
SwiftUI - presentationDetents behaves incorrectly on iOS 16–18 but works correctly on iOS 26
I'm using a custom modifier called AutoSheetDetentModifier to automatically size a sheet based on its content. On iOS 26, it works as expected: the content height is measured correctly and the sheet shrinks to match that height. However, on iOS 16, 17 and 18, the same code doesn’t work. The content height is still measured, but the sheet does not reduce its height. Instead, the sheet remains larger and the content appears vertically centered. (Note that content() includes ScrollView) public struct AutoSheetDetentModifier: ViewModifier { @State private var height: CGFloat = 380 // default value to avoid bouncing public func body(content: Content) -> some View { content .modifier(MeasureHeightViewModifier(height: $height)) .presentationDetents([.height(height)]) } } public struct MeasureHeightViewModifier: ViewModifier { @Binding var height: CGFloat public func body(content: Content) -> some View { content .fixedSize(horizontal: false, vertical: true) .background( GeometryReader { geo -> Color in DispatchQueue.main.async { height = geo.size.height } return Color.clear } ) } } extension View { public func applyAutoSheetDetent() -> some View { self .modifier(AutoSheetDetentModifier()) } } public var body: some View { VStack { header() content() // includes ScrollView footer() } .background(Color.customGray) .applyAutoSheetDetent() } func content() -> some View { ScrollView { VStack { ForEach(items) { item in itemRow(item) } } } .frame(maxHeight: UIScreen.main.bounds.height * 0.7) } Screenshot from iOS 26 (working as expected): Screenshot from iOS 18 (not working): How can I make .presentationDetents(.height) shrink the sheet correctly on iOS 16–18, the same way it does on iOS 26?
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Dec ’25
Running tests on multiple simulators and local mock servers
Hello, I have a question about running tests on multiple simulators. Currently, my company has a WDIO+Appium test suite with XCUITEST driver that runs on a single simulator through a mockttp proxy (we are intercepting and mocking some of the responses from our APIs and pass through the rest). In order to route the traffic we are currently using 'networksetup -setsecurewebproxy '. Everything works as expected. With growing number of tests we'd like to scale number of simulators on a single host to 3-5. We have a working setup but the problem are system-wide proxy settings routing traffic from multiple simulators, which we can't distinguish by UDID or any other means, we know of. We can spin multiple mock servers on the same machine but we are struggling to find the way to route the traffic on a simulator basis. In the end, both options are viable: 1 mock server running for multiple simulators N number of mock servers for N number of simulators Has anyone had the same/similar problem? How to approach this? We are currently running on Sequoia OSX and platform version 18.6. Thanks!
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Dec ’25
init(data: Data) for SwiftUI Image?
Is there any reason why the SwiftUI Image hasn’t a direct init(data: Data) like UIImage from UIKit? In my opinion it’s very unintuitive and expensive to create a UIImage in the first step to create a SwiftUI Image with Image(uiImage: UIImage) in the second step. In addition to that, this causes unnecessary UIKit imports. In my opinion this is a very obvious small in the API, so are there any reasons why it is what it is? Best regards
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