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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iOS18: UITabBarController.selectedViewController with UINavigationController
In a UITabBarController, its controllers are set to be UINavigationControllers. When programmatically setting the selectedViewController to a desired controller which is not currently displayed, the selected icon is correct however the actual view controller is still the previously selected. Pseudo code: tabController.controllers = [viewcontroller1, viewcontroller2, viewcontroller3].map{ UINavigationController(rootViewController: $0) } .... // let's say at some point tab bar is set to e.g. showing index 1 tabController.selectedController = tabController.controllers[0] // after this the icon of the 1st tab is correctly displayed, but the controller is still the one at index 1 I have noticed that if the controllers are simple UIViewController (not UINavigationController) upon setting the selectedViewController the TabController sets both icon and content correctly. But this is not the wanted setup and different UINavigationControllers are needed. Is this a new bug in iOS18? Any idea how to fix this (mis)behaviour?
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Main Thread blocked by synchronous property query (AVPlayer)
I want to play remote videos using an AVPlayer in my SwiftUI App. However, I can't fix the error: "Main thread blocked by synchronous property query on not-yet-loaded property (PreferredTransform) for HTTP(S) asset. This could have been a problem if this asset were being read from a slow network." My code looks like this atm: struct CustomVideoPlayer: UIViewControllerRepresentable { let myUrl: URL func makeCoordinator() -> Coordinator { return Coordinator(self) } func makeUIViewController(context: Context) -> AVPlayerViewController { let playerItem = AVPlayerItem(url: myUrl) let player = AVQueuePlayer(playerItem: playerItem) let playerViewController = AVPlayerViewController() playerViewController.player = player context.coordinator.setPlayerLooper(player: player, templateItem: playerItem) playerViewController.delegate = context.coordinator playerViewController.beginAppearanceTransition(true, animated: false) return playerViewController } func updateUIViewController(_ uiViewController: AVPlayerViewController, context: Context) { } static func dismantleUIViewController(_ uiViewController: AVPlayerViewController, coordinator: ()) { uiViewController.beginAppearanceTransition(false, animated: false) } class Coordinator: NSObject, AVPlayerViewControllerDelegate { var parent: CustomVideoPlayer var player: AVPlayer? = nil var playerLooper: AVPlayerLooper? = nil init(_ parent: CustomVideoPlayer) { self.parent = parent super.init() } func setPlayerLooper(player: AVQueuePlayer, templateItem: AVPlayerItem) { self.player = player playerLooper = AVPlayerLooper(player: player, templateItem: templateItem) } } } I already tried creating the AVPlayerItem/AVAsset on a background thread and I also tried loading the properties asynchronously before setting the player in makeUIViewController: let player = AVQueuePlayer(playerItem: nil) ... Task { let asset = AVAsset(url: myUrl) let _ = try await asset.load(.preferredTransform) let item = AVPlayerItem(asset: asset) player.replaceCurrentItem(with: item) } Nothing seems to fix the issue (btw: the main thread is actually blocked, there is a noticable animation hitch). Any help is much appreciated.
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Visual artifacts in LazyVStack
Some strange visual artifacts appeared in my app after updating Xcode to 16.0. The old version of the app was built with Xcode 15.x and working fine without any visual artifacts, but for the latest release I've used Xcode 16.0 and some strange visual artifacts appeared in LazyVStack on iOS 18.x. https://www.veed.io/view/828ed62c-a8ee-4102-846c-55b28a7f4b74?panel=share Anyone can help me with a fix or workaround ?
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Sheet presentationDetents breaks after rapid open/dismiss cycles
Basic Information Please provide a descriptive title for your feedback: Sheet presentationDetents breaks after rapid open/dismiss cycles Which platform is most relevant for your report? iOS Description Steps to Reproduce: Create a sheet with presentationDetents([.medium]) Rapidly perform these actions multiple times (usually 3-4 times): a. Open the sheet b. Immediately scroll down to dismiss Open the sheet again Observe that the sheet now appears at .large size, ignoring the .medium detent Expected Result: Sheet should consistently maintain .medium size regardless of how quickly it is opened and dismissed. Actual Result: After rapid open/dismiss cycles, the sheet ignores .medium detent and appears at .large size. Reproduction Rate: Occurs consistently after 3-4 rapid open/dismiss cycles More likely to occur with faster open/dismiss actions Configuration: iOS 18 Xcode 16.0 (16A242d) SwiftUI Device: iPhone 14
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Re-Visiting NSViewController.loadView's behaviour in 2024 and under macOS 15...
This is a post down memory lane for you AppKit developers and Apple engineers... TL;DR: When did the default implementation of NSViewController.loadView start making an NSView when there's no matching nib file? (I'm sure that used to return nil at some point way back when...) If you override NSViewController.loadView and call [super loadView] to have that default NSView created, is it safe to then call self.view within loadView? I'm refactoring some old Objective-C code that makes extensive use of NSViewController without any use of nibs. It overrides loadView, instantiates all properties that are views, then assigns a view to the view controller's view property. This seems inline with the documentation and related commentary in the header. I also (vaguely) recall this being a necessary pattern when not using nibs: @interface MyViewController: NSViewController // No nibs // No nibName @end @implementation MyViewController - (void)loadView { NSView *hostView = [[NSView alloc] initWithFrame:NSZeroRect]; self.button = [NSButton alloc...]; self.slider = [NSSlider alloc...]; [hostView addSubview:self.button]; [hostView addSubview:self.slider]; self.view = hostView; } @end While refactoring, I was surprised to find that if you don't override loadView and do all of the setup in viewDidLoad instead, then self.view on a view controller is non-nil, even though there was no nib file that could have provided the view. Clearly NSViewController has realized that: There's no nib file that matches nibName. loadView is not overridden. Created an empty NSView and assigned it to self.view anyways. Has this always been the behaviour or did it change at some point? I could have sworn that if there as no matching nib file and you didn't override loadView, then self.view would be nil. I realize some of this behaviour changed in 10.10, as noted in the header, but there's no mention of a default NSView being created. Because there are some warnings in the header and documentation around being careful when overriding methods related to view loading, I'm curious if the following pattern is considered "safe" in macOS 15: - (void)loadView { // Have NSViewController create a default view. [super loadView]; self.button = [NSButton...]; self.slider = [NSSlider...]; // Is it safe to call self.view within this method? [self.view addSubview:self.button]; [self.view addSubview:self.slider]; } Finally, if I can rely on NSViewController always creating an NSView for me, even when a nib is not present, then is there any recommendation on whether one should continue using loadView or instead move code the above into viewDidLoad? - (void)viewDidLoad { self.button = [NSButton...]; self.slider = [NSSlider...]; // Since self.view always seems to be non-nil, then what // does loadView offer over just using viewDidLoad? [self.view addSubview:self.button]; [self.view addSubview:self.slider]; } This application will have macOS 15 as a minimum requirement.
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MapSelection of MapFeatures and MKMapItems
I have a Map within a SwiftUI app that has the selection parameter set to an optional MapSelection. I need to be able to select MapFeatures which works as expected as well as MKMapItems which are added to the map. The MKMapItems are not selectable. Is it possible to make it such that the Map allows the user to select MKMapItems as well as MapFeatures?
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App that runs fine under Xcode 15 does not work on Xcode 16.
When I upgraded to Sequoia 15.1, an app that worked fine under OS 14 stopped working. Out of 4 views on the main screen, only 1 is visible. Yet, if I click where another view should be, I get the expected action so the views are there, just not visible. Only I can't see where I am clicking! I had to upgrade to Xcode 16 to recompile the app and run it in Debug mode. When I do, I get the following: NSBundle file:///System/Library/PrivateFrameworks/MetalTools.framework/ principal class is nil because all fallbacks have failed. Can't find or decode disabled use cases. applicationSupportsSecureRestorableState FWIW - the only view that actually shows up is the last subview added to the main view.
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MapFeature icon and color
I don't believe it's possible today to access the icon and tint color of a MapFeature although this would be incredibly helpful in the app that I'm building presently as I'm storing places in SwiftData and would like to use the same icon and tint color when listing places in the app. It would be awesome if this were possible in the next version of iOS, iPadOS visionOS etc., if not presently possible.
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Is it possible to generate nice PDF with gradient from SwiftUI view ?
I try to generate PDF from view. View is nice, there is a lot of transparency and many gradients (circular and linear). But if I use ImageRenderer in in a way that documentation suggest all transparency and gradients disappear. Is this bug or some feature? Is it way to generate vector graphic from view with transparency and gradients? PDF allows those features, so why not?
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SwiftUI FormView not updating after value creation/updating in a SubView
I'm developing a SwiftUI, CoreData / CloudKit App with Xcode 16.2 & Sequoia 15.2. The main CoreData entity has 20 NSManaged vars and 5 derived vars, the latter being computed from the managed vars and dependent computed vars - this somewhat akin to a spreadsheet. The data entry/updating Form is complex for each managed var because the user needs to be able to enter data in either Imperial or Metric units, and then switch (by Button) between units for viewing equivalents. This has to happen on an individual managed var basis, because some source data are in Imperial and others Metric. Consequently, I use a generalised SubView on the Form for processing the managed var (passed as a parameter with its identity) and then updating the CoreData Entity (about 100 lines of code in total): i.e. there are 20 uses of the generalised SubView within the Main Form. However, none of the SubViews triggers an update of the managed var in the Form, nor computations of the derived vars. On initial load of the app, the CoreData entity is retrieved and the computations happen correctly: thereafter not. No technique for refreshing either View works: e.g. trigger based on NSManagedObjectContextDidSave; nor does reloading the CoreData entity after Context Save (CoreData doesn't recognise changes at the attribute level anyway). If the SubView is removed and replaced with code within the Form View itself, then it works. However, this will require about 40 @State vars, 20 onCommits, etc - so it's not something I'm keen to do. Below is a much-simplified example of the problem. Form{ Section(header: Text("Test Record")){ Text(testRec.dateString ?? "n/a") TextField("Notes",text:$text) .onSubmit{ testRec.notes = text dataStore.contextSave() } //DoubleNumberEntry(testRec: testRec) - doesn't work TextField("Double",value:$numDbl,format: .number) // This works .onSubmit{ testRec.dblNum = numDbl dataStore.contextSave() } TextField("Integer",value: $numInt,format: .number) .onSubmit{ testRec.intNum = Int16(numInt) dataStore.contextSave() } Text(String(format:"%.2f",testRec.computation)) Section(header: Text("Computations")) { Text(String(format:"%.2f",testRec.computation)) Text(String(format:"%.2f",testRec.anotherComputation)) } } } A much simplified version of my NSManaged var entry/updating. struct DoubleNumberEntry: View { let dataStore = MainController.shared.dataStore var testRec : TestRec @State private var numDbl: Double init(testRec: TestRec) { self.testRec = testRec self.numDbl = testRec.dblNum } var body: some View { TextField("Double",value:$numDbl,format: .number) .onSubmit{ testRec.dblNum = numDbl dataStore.contextSave() } } } I'd appreciate any offered solution or advice. Regards, Michaela
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How To Create Dual Screen of AR using RealityView and SwiftUI iOS 18
I have this code to make ARVR Stereo View To Be Used in VR Box Or Google Cardboard, it uses iOS 18 New RealityView but it is not Act as an AR but rather Static VR on a Camera background so as I move the iPhone the cube move with it and that's not suppose to happen if its Anchored in a plane or to world coordinate. import SwiftUI import RealityKit struct ContentView : View { let anchor1 = AnchorEntity(.camera) let anchor2 = AnchorEntity(.camera) var body: some View { HStack (spacing: 0){ MainView(anchor: anchor1) MainView(anchor: anchor2) } .background(.black) } } struct MainView : View { @State var anchor = AnchorEntity() var body: some View { RealityView { content in content.camera = .spatialTracking let item = ModelEntity(mesh: .generateBox(size: 0.25), materials: [SimpleMaterial()]) anchor.addChild(item) content.add(anchor) anchor.position.z = -1.0 anchor.orientation = .init(angle: .pi/4, axis:[0,1,1]) } } } the thing is if I remove .camera like this let anchor1 = AnchorEntity() let anchor2 = AnchorEntity() It would work as AR Anchored to world coordinates but on the other hand is does not work but on the left view only not both views Meanwhile this was so easy before RealityView and SwiftUI by cloning the view like in ARSCNView Example : import UIKit import ARKit class ViewController: UIViewController, ARSCNViewDelegate, ARSessionDelegate { //create Any Two ARSCNView's in Story board // and link each to the next (dont mind dimensions) @IBOutlet var sceneView: ARSCNView! @IBOutlet var sceneView2: ARSCNView! override func viewDidLoad() { super.viewDidLoad() // Do any additional setup after loading the view. sceneView.delegate = self sceneView.session.delegate = self // Create SceneKit box let box = SCNBox(width: 0.1, height: 0.1, length: 0.1, chamferRadius: 0.01) let item = SCNNode(geometry: box) item.geometry?.materials.first?.diffuse.contents = UIColor.green item.position = SCNVector3(0.0, 0.0, -1.0) item.orientation = SCNVector4(0, 1, 1, .pi/4.0) // retrieve the ship node sceneView.scene.rootNode.addChildNode(item) } override func viewDidLayoutSubviews() // To Do Add the 4 Buttons { // Stop Screen Dimming or Closing While The App Is Running UIApplication.shared.isIdleTimerDisabled = true let screen: CGRect = UIScreen.main.bounds let topPadding: CGFloat = self.view.safeAreaInsets.top let bottomPadding: CGFloat = self.view.safeAreaInsets.bottom let leftPadding: CGFloat = self.view.safeAreaInsets.left let rightPadding: CGFloat = self.view.safeAreaInsets.right let safeArea: CGRect = CGRect(x: leftPadding, y: topPadding, width: screen.size.width - leftPadding - rightPadding, height: screen.size.height - topPadding - bottomPadding) DispatchQueue.main.async { if self.sceneView != nil { self.sceneView.frame = CGRect(x: safeArea.size.width * 0 + safeArea.origin.x, y: safeArea.size.height * 0 + safeArea.origin.y, width: safeArea.size.width * 0.5, height: safeArea.size.height * 1) } if self.sceneView2 != nil { self.sceneView2.frame = CGRect(x: safeArea.size.width * 0.5 + safeArea.origin.x, y: safeArea.size.height * 0 + safeArea.origin.y, width: safeArea.size.width * 0.5, height: safeArea.size.height * 1) } } } override func viewDidAppear(_ animated: Bool) { super.viewDidAppear(animated) let configuration = ARWorldTrackingConfiguration() sceneView.session.run(configuration) sceneView2.scene = sceneView.scene sceneView2.session = sceneView.session } } And here is the video for it
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Storing SwiftUI Views to operate on it
I am creating a UIKit application but that contains SwiftUI Views embedded using the hostingcontroller. I have a particular approach for it..but it requires instantiating a swiftUI view, creating a hostingcontroller object from it and storing a reference to it. So that later If I wanted to update the view, I can simply get the reference back and update the swiftUI view using it. I wanted to understand what does apple recommends on this. Can we store a swiftUI instance? Does it cause any issue or it is okay to do so?
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Results with spotlight in Core Data is not all.
I'm using Core Data to save data. Then I wanna add spotlight support. self.spotlightDelegate = StorageSpotlightDelegate(forStoreWith: description, coordinator: container.persistentStoreCoordinator) let isSpotlightDisable = UserDefaults.standard.bool(forKey: "isSpotlightDisable") if !isSpotlightDisable { self.toggleSpotlightIndexing(enable: true) } public func toggleSpotlightIndexing(enable: Bool) { guard let spotlightDelegate = spotlightDelegate else { return } if enable { spotlightDelegate.startSpotlightIndexing() } else { spotlightDelegate.stopSpotlightIndexing() spotlightDelegate.deleteSpotlightIndex { error in if let error = error { print(error) } } } UserDefaults.standard.set(!enable, forKey: "isSpotlightDisable") } It works fine on an iOS15 device, but not work on iOS 17&18. On iOS 18 devices, I can search the data when the first time to added to Core Data. But if I stop spotlight indexing and restart again, the data is never be searched. How can I to solve this? And I noticed that the problem is also exists in another dictionary app.
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MacOS 15.1, in the app designed for iPad, the image of UIAction in UIMenu does not display correctly.
code: let action1 = UIAction(title: "Restore".localized, image: UIImage(resource: .listRestore)) { [weak self] action in self?.trashRestoreTapped(id: button.tag) } let action2 = UIAction(title: "Delete".localized, image: UIImage(resource: .listDelete), attributes: [.destructive]) { [weak self] action in self?.trashDeleteTapped(id: button.tag) } button.menu = UIMenu(options: .displayInline, preferredElementSize: .large, children: [action1, action2]) button.showsMenuAsPrimaryAction = true MacOS 15.1: iPad:
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Scrolling is backwards with external devices when rotating to landscape mode
We recently converted an existing app to adopt scenes (for CarPlay). The app has one main view controller that presents a WKWebView to show our content. Everything works fine in both landscape and portait mode when swiping on the screen to scroll. But with an iPad using an external Magic Keyboard, once you rotate to landscape mode the scrolling gestures are reversed. Swiping vertically on the trackpad is scrolling the page horizontally and vice versa. When this happens an error like below is logged (this error also shows up when in portait mode, but scrolling works as expected): Unexpected window orientation: <UIWindow: 0x10370d8f0; orientation: landscapeLeft (4)> { hidden = NO; frame = {{0, 0}, {1180, 820}}; bounds = {{0, 0}, {1180, 820}}; ownsOrientation = NO; ownsOrientationTransform = NO; autorotationDisabled = NO; windowInterfaceOrientation = unknown (0); rootTransformOrientation = landscapeLeft (4); viewTransformOrientation = unknown (0); autorotationDisabled = NO; orientationVC = ... { providedSupportedOrientations = ( Pu Ll Lr Pd ); resolvedSupportedOrientations = ( Pu Ll Lr Pd ); canPreferOrientation = NO; }; }, event type: 6 It seems to suggest that while the view controller orientation is set correctly. It doesn't know what the orientation is for the window. I have been unable to figure out what would change with adopting scenes that would explain this behavior. I assume it has to do with the potential multi-window nature of it but haven't found any docs that describe how to ensure the window is setup to use the same orientation as the device. Any suggestions on things to check?
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ARVR RealityView Showing left Camera view Entity near more than the right view
I have this code to make ARVR Stereo View To Be Used in VR Box Or Google Cardboard, it uses iOS 18 New RealityView but for some reason the left side showing the Entity (Box) more near to the camera than the right side which make it not identical, I wonder is this a bug and need to be fixed or what ? thanx Here is the code import SwiftUI import RealityKit struct ContentView : View { let anchor1 = AnchorEntity(.camera) let anchor2 = AnchorEntity(.camera) var body: some View { HStack (spacing: 0){ MainView(anchor: anchor1) MainView(anchor: anchor2) } .background(.black) } } struct MainView : View { @State var anchor = AnchorEntity() var body: some View { RealityView { content in content.camera = .spatialTracking let item = ModelEntity(mesh: .generateBox(size: 0.25), materials: [SimpleMaterial()]) anchor.addChild(item) content.add(anchor) anchor.position.z = -1.0 anchor.orientation = .init(angle: .pi/4, axis:[0,1,1]) } } } And Here is the View
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Modifying SwiftData Object
Hi, The dataModule in code below is a swiftData object being passed to the view and its property as key path but when trying to modify it I'm getting the error ."Cannot assign through subscript: 'self' is immutable" how to solve this issue ? Kind Regards struct ListSel<T: PersistentModel>: View { @Bindable var dataModule: T @Binding var txtValue: String var keyPath: WritableKeyPath<T, String> var turncate: CGFloat? = 94.0 var image = "" var body: some View { HStack { Text(txtValue) .foregroundColor(sysSecondary) .font(.subheadline) .onChange(of: txtValue) { value in dataModule[keyPath: keyPath] = value } Image(systemName: image) .foregroundColor(sysSecondary) .font(.subheadline) .imageScale(.small) .symbolRenderingMode(.hierarchical) .scaleEffect(0.8) } .frame(width: turncate, height: 20, alignment: .leading) .truncationMode(.tail) } }
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Crash calling UIHostingController from a Swift Package
Hello team, We recently found a EXC_BAD_ACCESS crash when using UIHostingControllers on a SPM local Package in our application. This is happening from time to time when we run the app on simulators using Debug configurations. Also, this issue is consistent when we run application tests, there is something weird that we found after making a research... If we disable app test target and only keep packages tests, the crash is not happening, but as soon as we re-enable the app test target from the test suite the crash returns. This is the full error message: Thread 1: EXC_BAD_ACCESS (code=1, address=0xbad4017) A bad access to memory terminated the process. Is this s known issue? We've been performing explorations for some days and couldn't find any real solution for this. A basic call on UIHostingController inside of a SPM local Package is enough to make the app crash, nothing custom being done: UIHostingController(rootView: MyView())
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