Construct and manage graphical, event-driven user interfaces for iOS or tvOS apps using UIKit.

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Degraded RoomPlan performance
We have been using RoomPlan in our app for 2+ years. Through a combination of in-app and manual coaching on scanning best practices, most users are able to achieve high-quality scans on a consistent basis. In recent weeks, however, we have observed an increase in reports of degraded scanning performance, even from veteran users who had not previously encountered issues. The RoomCaptureView overlay is jittery and crooked, and the resulting scan file has significant issues, even for simple, well-lit rectangular rooms. It is difficult to troubleshoot these issues given the number of variables at play, and the overall volume of reports is still relatively low, but we'd appreciate any guidance on known issues or workarounds that could help unblock our users who are being affected by this. I noticed that this post includes an acknowledgement of FB14454922 and FB15035788. Our issues seem slightly different as the scans are simply inaccurate and jittery without failing outright. I haven't found any other threads on similar issues.
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Incorrect system color on popover view, and does not update while switching dark mode on iOS 26 beta 3
All system colors are displayed incorrectly on the popover view. Those are the same views present as a popover in light and dark mode. And those are the same views present as modal. And there is also a problem that when the popover is presented, switching to dark/light mode will not change the appearance. That affected all system apps. The following screenshot is already in dark mode. All those problem are occured on iOS 26 beta 3.
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Crash in UIKeyboardStateManager when repeatedly switching text input focus in WKWebView (hybrid app)
We’re building a hybrid iOS app using Angular (web) rendered inside a WKWebView, hosted by a native Swift app. Recently, we encountered a crash related to UIKeyboardStateManager in UIKit when switching between text inputs continuously within an Angular screen. Scenario The screen contains several text input fields. A “Next” button focuses the next input field programmatically. After about 61 continuous input field changes, the app crashes. It seems like this may be related to UIKit’s internal keyboard management while switching focus rapidly inside a WebView. crash stack: Crashed: com.apple.main-thread 0 WebKit 0xfbdad0 <redacted> + 236 1 UIKitCore 0x10b0548 -[UITextInteractionSelectableInputDelegate _moveToStartOfLine:withHistory:] + 96 2 UIKitCore 0xd0fb38 -[UIKBInputDelegateManager _moveToStartOfLine:withHistory:] + 188 3 UIKitCore 0xa16174 __158-[_UIKeyboardStateManager handleMoveCursorToStartOfLine:beforePublicKeyCommands:testOnly:savedHistory:force:canHandleSelectableInputDelegateCommand:keyEvent:]_block_invoke + 52 4 UIKitCore 0xa36ae4 -[_UIKeyboardStateManager performBlockWithTextInputChangesIgnoredForNonMacOS:] + 48 5 UIKitCore 0xa160f0 -[_UIKeyboardStateManager handleMoveCursorToStartOfLine:beforePublicKeyCommands:testOnly:savedHistory:force:canHandleSelectableInputDelegateCommand:keyEvent:] + 440 6 UIKitCore 0xa07010 -[_UIKeyboardStateManager handleKeyCommand:repeatOkay:options:] + 5760 7 UIKitCore 0xa2fb64 -[_UIKeyboardStateManager _handleKeyCommandCommon:options:] + 76 8 UIKitCore 0xa2fb08 -[_UIKeyboardStateManager _handleKeyCommand:] + 20 9 UIKitCore 0xa30684 -[_UIKeyboardStateManager handleKeyEvent:executionContext:] + 2464 10 UIKitCore 0xa2f95c __42-[_UIKeyboardStateManager handleKeyEvent:]_block_invoke + 40 11 UIKitCore 0x4b9460 -[UIKeyboardTaskEntry execute:] + 208 12 UIKitCore 0x4b92f4 -[UIKeyboardTaskQueue continueExecutionOnMainThread] + 356 13 UIKitCore 0x4b8be0 -[UIKeyboardTaskQueue addTask:breadcrumb:] + 120 14 UIKitCore 0x4a9ed0 -[_UIKeyboardStateManager _setupDelegate:delegateSame:hardwareKeyboardStateChanged:endingInputSessionIdentifier:force:delayEndInputSession:] + 3388 15 UIKitCore 0xfa290 -[_UIKeyboardStateManager setDelegate:force:delayEndInputSession:] + 628 16 UIKitCore 0xf617c -[UIKeyboardSceneDelegate _reloadInputViewsForKeyWindowSceneResponder:force:fromBecomeFirstResponder:] + 1140 17 UIKitCore 0xf5c88 -[UIKeyboardSceneDelegate _reloadInputViewsForResponder:force:fromBecomeFirstResponder:] + 88 18 UIKitCore 0x4fe4ac -[UIResponder(UIResponderInputViewAdditions) reloadInputViews] + 84 19 WebKit 0xfbe708 <redacted> + 100 20 WebKit 0xfbf594 <redacted> + 340 21 WebKit 0x8a33d8 <redacted> + 32 22 WebKit 0x8cee04 <redacted> + 144 23 WebKit 0x1c83f0 <redacted> + 22692 24 WebKit 0x73f40 <redacted> + 264 25 WebKit 0x162c7c <redacted> + 40 26 WebKit 0x1623b4 <redacted> + 1608 27 WebKit 0x73298 <redacted> + 268 28 WebKit 0x72e48 <redacted> + 660 29 JavaScriptCore 0xdb00 WTF::RunLoop::performWork() + 524 30 JavaScriptCore 0xd744 WTF::RunLoop::performWork(void*) + 36 31 CoreFoundation 0xf92c __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 28 32 CoreFoundation 0xf744 __CFRunLoopDoSource0 + 172 33 CoreFoundation 0xf5a0 __CFRunLoopDoSources0 + 232 34 CoreFoundation 0xff20 __CFRunLoopRun + 840 35 CoreFoundation 0x11adc CFRunLoopRunSpecific + 572 36 GraphicsServices 0x1454 GSEventRunModal + 168 37 UIKitCore 0x135274 -[UIApplication _run] + 816 38 UIKitCore 0x100a28 UIApplicationMain + 336 39 APP1 0xa2ed0 main + 21 (AppDelegate.swift:21) 40 ??? 0x1aa889f08 (シンボルが不足しています) From reviewing the crash log, it appears that the crash occurs inside UIKeyboardStateManager while handling keyboard or cursor updates. Questions Has anyone seen this specific crash pattern involving UIKeyboardStateManager? Are there known UIKit or WebKit bugs related to UIKeyboardStateManager when continuously changing focus between text fields (especially in WKWebView)? Any insights or workarounds would be greatly appreciated. Thanks!
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Detecting marked range in UI/NSTextViews at the time of shouldChangeTextIn
We have submitted a feedback for this issue: FB21230723 We're building a note-taking app for iOS and macOS that uses both UITextView and NSTextView. When performing text input that involves a marked range (such as Japanese input) in a UITextView or NSTextView with a UITextViewDelegate or NSTextViewDelegate set, the text view's marked range (markedTextRange / markedRange()) has not yet been updated at the moment when shouldChangeTextIn is invoked. UITextViewDelegate.textView(_:shouldChangeTextIn:replacementText:) NSTextViewDelegate.textView(_:shouldChangeTextIn:replacementString:) The current behavior is this when entering text in Japanese: (same for NSTextView) func textView(_ textView: UITextView, shouldChangeTextIn range: NSRange, replacementText text: String) -> Bool { print(textView.markedTextRange != nil) // prints out false DispatchQueue.main.async { print(textView.markedTextRange != nil) // prints out true } } However, we need the value of markedTextRange right away in order to determine whether to return true or false from this method. Is there any workaround for this issue?
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Crash in swift::_getWitnessTable when passing UITraitBridgedEnvironmentKey
When using UITraitBridgedEnvironmentKey to pass a trait value to the swift environment, it causes a crash when trying to access the value from the environment. The issue seems to be related to how swift uses the UITraitBridgedEnvironmentKey protocol since the crash occurs in swift::_getWitnessTable () from lazy protocol witness table accessor…. It can occur when calling any function that is generic using the UITraitBridgedEnvironmentKey type. I originally encountered the issue when trying to use a UITraitBridgedEnvironmentKey in SwiftUI, but have been able to reproduce the issue with any function with a similar signature. https://developer.apple.com/documentation/swiftui/environmentvalues/subscript(_:)-9zku Steps to Reproduce Requirements for the issue to occur Project with a minimum iOS version of iOS 16 Build the project with Xcode 26 Run on iOS 18 Add the following code to a project and call foo(key: MyCustomTraitKey.self) from anywhere. @available(iOS 17.0, *) func foo<K>(key: K.Type) where K: UITraitBridgedEnvironmentKey { // Crashes before this is called } @available(iOS 17.0, *) public enum MyCustomTraitKey: UITraitBridgedEnvironmentKey { public static let defaultValue: Bool = false public static func read(from traitCollection: UITraitCollection) -> Bool { false } public static func write(to mutableTraits: inout UIMutableTraits, value: Bool) {} } // The crash will occur when calling this. It can be added to a project anywhere // The sample project calls it from scene(_:willConnectTo:options:) foo(key: MyCustomTraitKey.self) For example, I added it to the SceneDelegate in a UIKit Project class SceneDelegate: UIResponder, UIWindowSceneDelegate { var window: UIWindow? func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) { if #available(iOS 17, *) { // The following line of code can be placed anywhere in a project, `SceneDelegate` is just a convenient place to put it to reproduce the issue. foo(key: MyCustomTraitKey.self) // ^ CRASH: Thread 1: EXC_BAD_ACCESS (code=1, address=0x10) } } } Actual Behaviour The app crashes with the stack trace showing the place calling foo but before foo is actually called. (ie, a breakpoint or print in foo is never hit) #0 0x000000019595fbc4 in swift::_getWitnessTable () #1 0x0000000104954128 in lazy protocol witness table accessor for type MyCustomTraitKey and conformance MyCustomTraitKey () #2 0x0000000104953bc4 in SceneDelegate.scene(_:willConnectTo:options:) at .../SceneDelegate.swift:20 The app does not crash when run on iOS 17, or 26 or when the minimum ios version is raised to iOS 17 or higher. It also doesn't crash on iOS 16 since it's not calling foo since UITraitBridgedEnvironmentKey was added in iOS 17. Expected behaviour The app should not crash. It should call foo on iOS 17, 18, and 26.
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Question: How to support landscape-only on iPad app after 'Support for all orientations will soon be required' warning
Dear Apple Customer Support, I’m developing a new Swift iPadOS app and I want the app to run in landscape only (portrait disabled). In Xcode, under Target &gt; General &gt; Deployment Info &gt; Device Orientation, if I select only Landscape Left and Landscape Right, the app builds successfully, but during upload/validation I receive this message and the upload is blocked: “Update the Info.plist: Support for all orientations will soon be required.” Could you please advise what the correct/recommended way is to keep an iPad app locked to landscape only while complying with the current App Store upload requirements? Is there a specific Info.plist configuration (e.g., UISupportedInterfaceOrientations~ipad) or another setting that should be used? Thank you,
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Change tint of back button in UINavigationItem on iOS 26
I am struggling to change the tint of the back button in an UINavigationItem. In iOS 18.6 it looks like this while on iOS 26 the same looks like this I can live without the Dictionary but I'd like to get the blue color back. In viewDidLoad() I have tried navigationItem.backBarButtonItem?.tintColor = .link but this did not work since navigationItem.backBarButtonItem is nil. My second attempt was navigationController?.navigationBar.tintColor = .link but this didn't work either. I have even set the Global Tint to Link Color but this had no effect either. Does anyone have an idea how to change the tint of the back button in an UINavigationItem on iOS 26?
Topic: UI Frameworks SubTopic: UIKit Tags:
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"canOpenURL:" on a thread that isn`t main thread?
When I call this method on a thread that isn`t thread. And chose main thread check on target, The Console show the world : Main Thread Checker: UI API called on a background thread: -[UIApplication canOpenURL:] PID: 8818, TID: 10191278, Thread name: (none), Queue name: com.myqueue.canopen, QoS: 0 Backtrace: 4 TestDemo 0x0000000102f6c068 __39-[AppTools isExists:]_block_invoke_3 + 892 5 CoreFoundation 0x000000019e22995c 7519E999-1053-3367-B9D5-8844F6D3BDC6 + 1042780 6 CoreFoundation 0x000000019e12ec98 7519E999-1053-3367-B9D5-8844F6D3BDC6 + 15512 7 TestDemo 0x0000000102f6bba0 __39-[AppTools isExists:]_block_invoke_2 + 424 8 libdispatch.dylib 0x0000000103a4d7fc _dispatch_call_block_and_release + 24 9 libdispatch.dylib 0x0000000103a4ebd8 _dispatch_client_callout + 16 10 libdispatch.dylib 0x0000000103a55b48 _dispatch_lane_serial_drain + 744 11 libdispatch.dylib 0x0000000103a566e4 _dispatch_lane_invoke + 448 12 libdispatch.dylib 0x0000000103a61adc _dispatch_workloop_worker_thread + 1324 13 libsystem_pthread.dylib 0x000000019df72b88 _pthread_wqthread + 276 14 libsystem_pthread.dylib 0x000000019df75760 start_wqthread + 8
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Text with Liquid Glass effect
I'm looking for a way to implement Liquid Glass effect in a Text, and I have issues. If I want to do gradient effect in a Text, no problem, like below. Text("Liquid Glass") .font(Font.system(size: 30, weight: .bold)) .multilineTextAlignment(.center) .foregroundStyle( LinearGradient( colors: [.blue, .mint, .green], startPoint: .leading, endPoint: .trailing ) ) But I cannot make sure that I can apply the .glassEffect with .mask or .foregroundStyle. The Glass type and Shape type argument looks like not compatible with the Text shape itself. Any solution to do this effect on Text ? Thanks in advance for your answers.
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[UIKit Glass Effect] - Opacity change from 0 to 1 does not work
When a UIVisualEffect with glass effect view is added with opacity 0, it remains hidden as expected. But when changing it back to 1 should make it visible, but currently it stays hidden forever. The bug is only reproducible on iOS 26.1 and iOS 26.2. It does not happen on iOS 26.0. The issue is also not reproducible with UIBlurEffect. Only happens for Glass effect Here is the repro link
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Keyframe animation crashes with +[_SwiftUILayerDelegate _screen]: unrecognized selector sent to class on iOS 26
We have an UIViewController called InfoPlayerViewController. Its main subview is from a child view controller backed by SwiftUI via UIHostingController. The InfoPlayerViewController conforms to UIViewControllerTransitioningDelegate. The animation controller for dismissing is DismissPlayerAnimationController. It runs UIKit keyframe animations via UIViewPropertyAnimator. When the keyframe animation is executed there’s an occasional crash for end users in production. It only happens on iOS 26. FB Radar: FB20871547 An example crash is below. Exception Type: EXC_CRASH (SIGABRT) Exception Codes: 0x0000000000000000, 0x0000000000000000 Exception Reason: +[_SwiftUILayerDelegate _screen]: unrecognized selector sent to class 0x20c95da08 Termination Reason: SIGNAL 6 Abort trap: 6 Triggered by Thread: 0 Last Exception Backtrace: 0 CoreFoundation 0x1a23828c8 __exceptionPreprocess + 164 (NSException.m:249) 1 libobjc.A.dylib 0x19f2f97c4 objc_exception_throw + 88 (objc-exception.mm:356) 2 CoreFoundation 0x1a241e6cc +[NSObject(NSObject) doesNotRecognizeSelector:] + 364 (NSObject.m:158) 3 CoreFoundation 0x1a22ff4f8 ___forwarding___ + 1472 (NSForwarding.m:3616) 4 CoreFoundation 0x1a23073a0 _CF_forwarding_prep_0 + 96 (:-1) 5 UIKitCore 0x1a948e880 __35-[UIViewKeyframeAnimationState pop]_block_invoke + 300 (UIView.m:2973) 6 CoreFoundation 0x1a22cb170 __NSDICTIONARY_IS_CALLING_OUT_TO_A_BLOCK__ + 24 (NSDictionaryHelpers.m:10) 7 CoreFoundation 0x1a245d7cc -[__NSDictionaryM enumerateKeysAndObjectsWithOptions:usingBlock:] + 288 (NSDictionaryM.m:271) 8 UIKitCore 0x1a948e6bc -[UIViewKeyframeAnimationState pop] + 376 (UIView.m:2955) 9 UIKitCore 0x1a7bc40e8 +[UIViewAnimationState popAnimationState] + 60 (UIView.m:1250) 10 UIKitCore 0x1a94acc44 +[UIView(UIViewAnimationWithBlocks) _setupAnimationWithDuration:delay:view:options:factory:animations:start:animationStateGenerator:completion:] + 684 (UIView.m:17669) 11 UIKitCore 0x1a94ae334 +[UIView(UIViewKeyframeAnimations) animateKeyframesWithDuration:delay:options:animations:completion:] + 224 (UIView.m:17945) 12 MyApp 0x102c78dec static UIView.animateNestedKeyframe(withRelativeStartTime:relativeDuration:animations:) + 208 (UIView+AnimateNestedKeyframe.swift:10) 13 MyApp 0x102aef3c0 closure #1 in DismissPlayerAnimationController.slideDownBelowTabBarTransitionAnimator(using:) + 156 (DismissPlayerAnimationController.swift:229) 14 MyApp 0x102a2d3d4 <deduplicated_symbol> + 28 15 UIKitCore 0x1a7d5ae5c -[UIViewPropertyAnimator _runAnimations] + 172 (UIViewPropertyAnimator.m:2123) 16 UIKitCore 0x1a83e1594 __49-[UIViewPropertyAnimator startAnimationAsPaused:]_block_invoke_3 + 92 (UIViewPropertyAnimator.m:3557) 17 UIKitCore 0x1a83e1464 __49-[UIViewPropertyAnimator startAnimationAsPaused:]_block_invoke + 96 (UIViewPropertyAnimator.m:3547) 18 UIKitCore 0x1a83e1518 __49-[UIViewPropertyAnimator startAnimationAsPaused:]_block_invoke_2 + 144 (UIViewPropertyAnimator.m:3553) 19 UIKitCore 0x1a83e0e64 -[UIViewPropertyAnimator _setupAnimationTracking:] + 100 (UIViewPropertyAnimator.m:3510) 20 UIKitCore 0x1a83e1264 -[UIViewPropertyAnimator startAnimationAsPaused:] + 728 (UIViewPropertyAnimator.m:3610) 21 UIKitCore 0x1a83de42c -[UIViewPropertyAnimator pauseAnimation] + 68 (UIViewPropertyAnimator.m:2753) 22 UIKitCore 0x1a87d5328 -[UIPercentDrivenInteractiveTransition _startInterruptibleTransition:] + 244 (UIViewControllerTransitioning.m:982) 23 UIKitCore 0x1a87d5514 -[UIPercentDrivenInteractiveTransition startInteractiveTransition:] + 184 (UIViewControllerTransitioning.m:1012) 24 UIKitCore 0x1a7c7931c ___UIViewControllerTransitioningRunCustomTransitionWithRequest_block_invoke_3 + 152 (UIViewControllerTransitioning.m:1579) 25 UIKitCore 0x1a892aefc +[UIKeyboardSceneDelegate _pinInputViewsForKeyboardSceneDelegate:onBehalfOfResponder:duringBlock:] + 96 (UIKeyboardSceneDelegate.m:3518) 26 UIKitCore 0x1a7c79238 ___UIViewControllerTransitioningRunCustomTransitionWithRequest_block_invoke_2 + 236 (UIViewControllerTransitioning.m:1571) 27 UIKitCore 0x1a94ab4b8 +[UIView(Animation) _setAlongsideAnimations:toRunByEndOfBlock:animated:] + 188 (UIView.m:17089) 28 UIKitCore 0x1a7c79070 _UIViewControllerTransitioningRunCustomTransitionWithRequest + 556 (UIViewControllerTransitioning.m:1560) 29 UIKitCore 0x1a86cb7cc __77-[UIPresentationController runTransitionForCurrentStateAnimated:handoffData:]_block_invoke_3 + 1784 (UIPresentationController.m:1504) 30 UIKitCore 0x1a7c43888 -[_UIAfterCACommitBlock run] + 72 (_UIAfterCACommitQueue.m:137) 31 UIKitCore 0x1a7c437c0 -[_UIAfterCACommitQueue flush] + 168 (_UIAfterCACommitQueue.m:228) 32 UIKitCore 0x1a7c436d0 _runAfterCACommitDeferredBlocks + 260 (UIApplication.m:3297) 33 UIKitCore 0x1a7c43c34 _cleanUpAfterCAFlushAndRunDeferredBlocks + 80 (UIApplication.m:3275) 34 UIKitCore 0x1a7c1f104 _UIApplicationFlushCATransaction + 72 (UIApplication.m:3338) 35 UIKitCore 0x1a7c1f024 __setupUpdateSequence_block_invoke_2 + 352 (_UIUpdateScheduler.m:1634) 36 UIKitCore 0x1a7c2cee8 _UIUpdateSequenceRunNext + 128 (_UIUpdateSequence.mm:189) 37 UIKitCore 0x1a7c2c378 schedulerStepScheduledMainSectionContinue + 60 (_UIUpdateScheduler.m:1185) 38 UpdateCycle 0x28c58f5f8 UC::DriverCore::continueProcessing() + 84 (UCDriver.cc:288) 39 CoreFoundation 0x1a2323230 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 28 (CFRunLoop.c:2021) 40 CoreFoundation 0x1a23231a4 __CFRunLoopDoSource0 + 172 (CFRunLoop.c:2065) 41 CoreFoundation 0x1a2300c6c __CFRunLoopDoSources0 + 232 (CFRunLoop.c:2102) 42 CoreFoundation 0x1a22d68b0 __CFRunLoopRun + 820 (CFRunLoop.c:2983) 43 CoreFoundation 0x1a22d5c44 _CFRunLoopRunSpecificWithOptions + 532 (CFRunLoop.c:3462) 44 GraphicsServices 0x2416a2498 GSEventRunModal + 120 (GSEvent.c:2049) 45 UIKitCore 0x1a7c50ddc -[UIApplication _run] + 792 (UIApplication.m:3899) 46 UIKitCore 0x1a7bf5b0c UIApplicationMain + 336 (UIApplication.m:5574) // ...
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iOS 26 + UINavigationBar crash in layoutSubViews - new observation tracking
My #1 crash report since iOS 26 is the following: 1 libobjc.A.dylib objc_exception_throw 2 Foundation -[NSAssertionHandler handleFailureInMethod:object:file:lineNumber:description:] 3 UIKitCore -[UINavigationBar layoutSubviews] 4 UIKitCore UIView._layoutSubviewsWithObservationTracking() 5 UIKitCore @objc UIView._layoutSubviewsWithObservationTracking() Thread 0 9 libobjc.A.dylib objc_exception_throw 10 Foundation -[NSAssertionHandler handleFailureInMethod:object:file:lineNumber:description:] 11 UIKitCore -[UINavigationBar layoutSubviews] 12 UIKitCore UIView._layoutSubviewsWithObservationTracking() 13 UIKitCore @objc UIView._layoutSubviewsWithObservationTracking() I tried many things, without success so far. It seemed related to the new view update with observation tracking: link to documentation Any lead on how I should investigate this? Many thanks in advance!!
Topic: UI Frameworks SubTopic: UIKit Tags:
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UIKit - Stop ongoing animation on the extended setVisibleMapRect Animation time on MapKit
Hi team, I've been trying to extend the animation when we call the function setVisibleMapRect, we can use UIView.animate to lengthen the animation time, but one thing that I found not working is that when I extend the animation to 3, 5, or 10 seconds, and the changes is still ongoing and there's a gesture performed, the map will completely ignore the gesture. Causing the map to be having this kind of like "delayed" or "freeze" experience for the user. The map will immediately move to the final rect and ignores the user gesture. I've been checking on this problem for a week now and I'm quite stuck. I've tried using CADisplayLink to manually animate the camera per system fresh rate, it works very well, I can stop the camera movement anytime there are touches, but it causes the resource CPU spikes. Removing the animation layers recursively on sublayers and subviews also doesn't help. While storing the animation into a UIViewPropertyAnimator and use stopAnimation will always ignores user first interactions too while also animating the camera to the final position (which is not expected).
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Issue keeping scroll position in SwiftUI
Hey there, Link to the sample project: https://github.com/dev-loic/AppleSampleScrolling Context We are working on creating a feed of posts in SwiftUI. So far, we have successfully implemented a classic feed that opens from the top, with bottom pagination — a standard use case. Our goal, however, is to allow the feed to open from any post, not just the first one. For example, we would like to open the feed directly at the 3rd post and then trigger a network call to load elements both above and below it. Our main focus here is on preserving the scroll position while opening the screen and waiting for the network call to complete. To illustrate the issue, I created a sample project (attached) with two screens: MainView, which contains buttons to open the feed in different states. ScrollingView, which initially shows a single element, simulates a 3-second network call, and then populates with new data depending on which button was tapped. I am currently using Xcode 26 beta 6, but I can also reproduce this issue on Xcode 16.3. Tests on sample project I click on a button and just wait the 3 seconds for the call. In this scenario, I expect that the “focused item” stays at the exact same place on the screen. I also expect to see items below and above being added. Simulator iPhone 16 / iOS 18.4 with itemsHeight = 100 position = 0, 1, 2, 3 ⇒ works as expected position = 4, 5, 6, 7, 8, 9 ⇒ scroll is reset to the top and we loose the focused item Simulator iPhone 16 / iOS 18.4 with itemsHeight = 500 position = 0, 1, 2, 3, 4 ⇒ works as expected position = 5, 6, 7 ⇒ I have a glitch (the focused element moves on the screen) but the focused element is still visible position = 8, 9 ⇒ scroll is reset to the top and we loose the focused item Simulator iPhone 16 / iOS 26 with itemsHeight = 100 or 500 position = 0, 1, 2, 3, 4 ⇒ works as expected position = 5, 6, 7, 8, 9 ⇒ I have a glitch (the focused element moves on the screen) but the focused element is still visible Device iPhone 15 / iOS 26 with itemsHeight = 100 position = 0, 1, 2, 3, 4 ⇒ works as expected position = 5, 6, 7, 8, 9 ⇒ I have a glitch (the focused element moves on the screen) but the focused element is still visible Device iPhone 15 / iOS 26 with itemsHeight = 500 position = 0, 1, 2, 3 ⇒ works as expected position = 4, 5, 6, 7, 8, 9 ⇒ I have a glitch (the focused element moves on the screen) but the focused element is still visible Not any user interaction Moreover, in this scenario, the user does not interact with the screen during the simulated network call. Regardless of the situation, if the ScrollView is in motion, its position always resets to the top. This behavior prevents us from implementing automatic pagination when scrolling upward, which is ultimately our goal. My conclusion so far As far as I know it seems not possible to have both keeping scroll possible and upward automatic pagination using a SwiftUI LazyVStack inside a ScrollView. This appears to be standard behavior in messaging apps or other feed-based apps, and I’m wondering if I might be missing something. Thank you in advance for any guidance you can provide on this topic. Cheers
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Setting `navigationItem.standardAppearance` overrides backButtonImage setting
Hello everybody. I need your help with configuring navigationItem properly. I want to use its appearance properties to configure how the navigation bar looks on per-screen basis without interacting with UINavigationBar directly (the API has been implemented for this specific use case, right?) What I'm confused about is that setting any appearance property resets back button image to the default chevron. What I do now: Inside my app delegate let navigationBarAppearance = UINavigationBar.appearance() navigationBarAppearance.backIndicatorImage = UIImage() navigationBarAppearance.backIndicatorTransitionMaskImage = UIImage() I do this to hide the default chevron to customize back button appearance on per-view-controller basis Then in my presenting view controller: override func viewDidLoad() { super.viewDidLoad() navigationItem.title = "Root" navigationItem.backBarButtonItem = UIBarButtonItem( title: nil, image: nil, primaryAction: UIAction( title: "", image: UIImage(systemName: "square.and.arrow.up"), identifier: nil, discoverabilityTitle: nil, attributes: [], state: .on, handler: { [weak self] _ in self?.navigationController?.popViewController(animated: true) } ), menu: nil ) let appearance = UINavigationBarAppearance() appearance.configureWithTransparentBackground() appearance.backgroundColor = UIColor.red appearance.titleTextAttributes = [ .foregroundColor: UIColor.purple ] appearance.largeTitleTextAttributes = [ .foregroundColor: UIColor.purple ] navigationItem.standardAppearance = appearance navigationItem.compactAppearance = appearance navigationItem.scrollEdgeAppearance = appearance navigationItem.compactScrollEdgeAppearance = appearance } The colors are set up as expected, however the default chevron image appears on the next view controller next to square.and.arrow.up. If I don't touch navigation item appearance properties - only square.and.arrow.up is displayed, as I want, but obviously I loose all the customization. Can anyone please explain how to set things up properly? Thanks!
Topic: UI Frameworks SubTopic: UIKit Tags:
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167
2w
iOS app crash at -[UIView _wrappedProcessTraitChanges:withBehavior:] + 1288 (UIView.m:0)
Hello Apple engineers, could you help me understand whether this crash is a UIKit bug or something in our code that causes it. Based on the documentation it is an invalid fetch instruction, that's why I suspect UIKit. I've found a similar crash here on the forums reported a year ago, it seemed to be a UIKit bug - https://forums.developer.apple.com/forums/thread/729448. I've attached the full crash report (the app name was replaced with ): Thread 0 Crashed: 0 libobjc.A.dylib 0x000000019daf7c20 objc_msgSend + 32 (:-1) 1 UIKitCore 0x00000001a3020c50 -[UIView _wrappedProcessTraitChanges:withBehavior:] + 1288 (UIView.m:0) 2 UIKitCore 0x00000001a3020720 -[UIView _processChangesFromOldTraits:toCurrentTraits:withBehavior:] + 196 (UIView.m:7840) 3 UIKitCore 0x00000001a3020618 -[UIView _updateTraitCollectionAndProcessChangesWithBehavior:previousCollection:] + 112 (UIView.m:7831) 4 UIKitCore 0x00000001a2fa90c0 -[UIView(CALayerDelegate) layoutSublayersOfLayer:] + 944 (UIView.m:19850) 5 QuartzCore 0x00000001a22dfc28 CA::Layer::layout_if_needed(CA::Transaction*) + 496 (CALayer.mm:10944) 6 QuartzCore 0x00000001a22df7b4 CA::Layer::layout_and_display_if_needed(CA::Transaction*) + 148 (CALayer.mm:2638) 7 QuartzCore 0x00000001a2336914 CA::Context::commit_transaction(CA::Transaction*, double, double*) + 472 (CAContextInternal.mm:2613) 8 QuartzCore 0x00000001a22b57c4 CA::Transaction::commit() + 648 (CATransactionInternal.mm:420) 9 QuartzCore 0x00000001a22f8a0c CA::Transaction::flush_as_runloop_observer(bool) + 88 (CATransactionInternal.mm:928) 10 UIKitCore 0x00000001a303f568 _UIApplicationFlushCATransaction + 52 (UIApplication.m:3326) 11 UIKitCore 0x00000001a303cb64 __setupUpdateSequence_block_invoke_2 + 332 (_UIUpdateScheduler.m:1652) 12 UIKitCore 0x00000001a303c9d8 _UIUpdateSequenceRun + 84 (_UIUpdateSequence.mm:136) 13 UIKitCore 0x00000001a303c628 schedulerStepScheduledMainSection + 172 (_UIUpdateScheduler.m:1171) 14 UIKitCore 0x00000001a303d59c runloopSourceCallback + 92 (_UIUpdateScheduler.m:1334) 15 CoreFoundation 0x00000001a080c328 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 28 (CFRunLoop.c:1970) 16 CoreFoundation 0x00000001a080c2bc __CFRunLoopDoSource0 + 176 (CFRunLoop.c:2014) 17 CoreFoundation 0x00000001a0809dc0 __CFRunLoopDoSources0 + 244 (CFRunLoop.c:2051) 18 CoreFoundation 0x00000001a0808fbc __CFRunLoopRun + 840 (CFRunLoop.c:2969) 19 CoreFoundation 0x00000001a0808830 CFRunLoopRunSpecific + 588 (CFRunLoop.c:3434) 20 GraphicsServices 0x00000001ec7e81c4 GSEventRunModal + 164 (GSEvent.c:2196) 21 UIKitCore 0x00000001a336eeb0 -[UIApplication _run] + 816 (UIApplication.m:3844) 22 UIKitCore 0x00000001a341d5b4 UIApplicationMain + 340 (UIApplication.m:5496) 23 UIKitCore 0x00000001a3757fa8 UIApplicationMain(_:_:_:_:) + 104 (UIKit.swift:565) 24 <Redacted> 0x00000001028bde64 specialized static UIApplicationDelegate.main() + 28 (/<compiler-generated>:16) 25 <Redacted> 0x00000001028bde64 static AppDelegate.$main() + 28 (AppDelegate.swift:0) 26 <Redacted> 0x00000001028bde64 main + 116 27 dyld 0x00000001c61f6ec8 start + 2724 (dyldMain.cpp:1334) 2024-12-27_20-53-28.2129_-0500-353aaa194e6232c0d1fae767296bdb8c47c30498.crash
3
1
589
2w
Using Content Inset Adjustments on macOS Tahoe with Liquid Glass in nested NSScrollViews inside Sidebar
I have the following code (compile as a standalone file): #import <Cocoa/Cocoa.h> @interface AppDelegate : NSObject <NSApplicationDelegate> @property (strong) NSWindow *window; @end @implementation AppDelegate - (void)applicationDidFinishLaunching:(NSNotification *)notification { // Create main window self.window = [[NSWindow alloc] initWithContentRect:NSMakeRect(100, 100, 800, 600) styleMask:(NSWindowStyleMaskTitled | NSWindowStyleMaskClosable | NSWindowStyleMaskResizable | NSWindowStyleMaskMiniaturizable) backing:NSBackingStoreBuffered defer:NO]; [self.window setTitle:@"Nested ScrollView Demo"]; [self.window makeKeyAndOrderFront:nil]; // Split view controller NSSplitViewController *splitVC = [[NSSplitViewController alloc] init]; // Sidebar NSViewController *sidebarVC = [[NSViewController alloc] init]; sidebarVC.view = [[NSView alloc] initWithFrame:NSMakeRect(0, 0, 200, 600)]; sidebarVC.view.wantsLayer = YES; NSSplitViewItem *sidebarItem = [NSSplitViewItem sidebarWithViewController:sidebarVC]; sidebarItem.minimumThickness = 150; sidebarItem.maximumThickness = 400; [splitVC addSplitViewItem:sidebarItem]; // Content view controller NSViewController *contentVC = [[NSViewController alloc] init]; // Vertical scroll view (outer) NSScrollView *verticalScrollView = [[NSScrollView alloc] initWithFrame:NSMakeRect(0, 0, 600, 600)]; verticalScrollView.automaticallyAdjustsContentInsets = YES; verticalScrollView.hasVerticalScroller = YES; verticalScrollView.hasHorizontalScroller = NO; verticalScrollView.autoresizingMask = NSViewWidthSizable | NSViewHeightSizable; NSView *verticalContent = [[NSView alloc] initWithFrame:NSMakeRect(0, 0, 600, 1200)]; verticalContent.wantsLayer = YES; verticalContent.layer.backgroundColor = [[NSColor blueColor] CGColor]; [verticalScrollView setDocumentView:verticalContent]; // Add several horizontal scroll sections CGFloat sectionHeight = 150; for (int i = 0; i < 5; i++) { // Horizontal scroll view inside section NSScrollView *horizontalScroll = [[NSScrollView alloc] initWithFrame:NSMakeRect(0, verticalContent.frame.size.height - (i+1)*sectionHeight - i*20, 600, sectionHeight)]; horizontalScroll.hasHorizontalScroller = YES; horizontalScroll.hasVerticalScroller = NO; horizontalScroll.autoresizingMask = NSViewWidthSizable | NSViewHeightSizable; NSView *horizontalContent = [[NSView alloc] initWithFrame:NSMakeRect(0, 0, 1200, sectionHeight)]; horizontalContent.wantsLayer = YES; // Add labels horizontally for (int j = 0; j < 6; j++) { NSTextField *label = [NSTextField labelWithString:[NSString stringWithFormat:@"Item %d-%d", i+1, j+1]]; label.frame = NSMakeRect(20 + j*200, sectionHeight/2 - 15, 180, 30); [horizontalContent addSubview:label]; } horizontalScroll.documentView = horizontalContent; [verticalContent addSubview:horizontalScroll]; } contentVC.view = verticalScrollView; NSSplitViewItem *contentItem = [NSSplitViewItem splitViewItemWithViewController:contentVC]; contentItem.automaticallyAdjustsSafeAreaInsets = YES; contentItem.minimumThickness = 300; [splitVC addSplitViewItem:contentItem]; self.window.contentViewController = splitVC; // Sidebar label NSTextField *label = [NSTextField labelWithString:@"Sidebar"]; label.translatesAutoresizingMaskIntoConstraints = NO; [sidebarVC.view addSubview:label]; [NSLayoutConstraint activateConstraints:@[ [label.centerXAnchor constraintEqualToAnchor:sidebarVC.view.centerXAnchor], [label.centerYAnchor constraintEqualToAnchor:sidebarVC.view.centerYAnchor] ]]; } @end int main(int argc, const char * argv[]) { @autoreleasepool { NSApplication *app = [NSApplication sharedApplication]; AppDelegate *delegate = [[AppDelegate alloc] init]; [app setDelegate:delegate]; [app run]; } return 0; } Obviously, since the contents of the right part (the content of the sidebar) has its content inset, the horizontal scrolling views cannot extend to the left beneath the sidebar. I can change line 39 to say verticalScrollView.automaticallyAdjustsContentInsets = NO; which will make the inner horizontal scroll views able to extend below the sidebar, but then I'd lose out on the automatic inset management to not have other content overlap beneath the sidebar. So what can I do here? I've tried manually changing the frame of the inner scroll views to start on a negative x, but that does not allow me to scroll all the way to the leftmost content. I'm hoping I won't have to adjust for safe areas manually for the outer scroll view. I'd also appreciate tips on how to fix the fact that veritical scrolling doesn't work when your mouse is in a horizontal scroll view. Thanks! P.S. same thing also exists on UIKit.
0
0
127
3w