As of iOS 14, UICollectionViewDiffableDataSource has a reorderHandlers property. It's demonstrated in some sample code and talked about in WWDC 2020 session on Advances in Diffable Data Sources. The presenter states that you have to provide a canReorder and didReorder closure to enable the feature. The sample code uses it in a collection view with a list layout configuration, and configures the list cells with reorder accessories. The canReorder and didReorder methods are called as expected. But if I remove the reorder accessories from the cells, reordering no longer works - it doesn't call either closure. It also doesn't work in my app, where I have a grid layout using a compositional layout. How do I enable reordering on UICollectionViewDiffableDataSource without list cells and reorder accessories?

I have an iPad app in which I'm starting to support multiple windows / scenes. I have one main window type, let's say MainScene, and at least one secondary window type for opening specific types of content, say DetailScene. I have not declared my scene types in Info.plist. I have implemented application:configurationForConnectingSceneSession:options: like this: -(UISceneConfiguration *)application:(UIApplication *)application configurationForConnectingSceneSession:(UISceneSession *)connectingSceneSession options:(UISceneConnectionOptions *)options { NSUserActivity *activity = options.userActivities.anyObject; NSString *activityType = activity.activityType; if ([activityType isEqualToString:@"detailType"]) return [DetailSceneDelegate makeSceneConfiguration]; return [MainSceneDelegate makeSceneConfiguration]; } Say I perform these steps: Launch app for the first time. I get a call to configurationForConnectingSceneSession, and the activity type is nil so it returns a MainScene. Open a new window for some piece of content. That uses the detail scene activity type, so configurationForConnectingSceneSession returns a DetailScene. Creating the new scene looks like this: NSUserActivity *activity = [[NSUserActivity alloc] initWithActivityType:@"detailType"]; activity.userInfo = @{@"content_id": @(contentRowId)}; [[UIApplication sharedApplication] requestSceneSessionActivation:nil userActivity:activity options:nil errorHandler:nil]; Suspend the app and open the app switcher. Discard (by flicking up) first the main window and then the detail window. The app is now killed. Relaunch the app. At this point I do not get a call to configurationForConnectingSceneSession. I get the detail scene back, restored from its user activity, with calls straight to DetailSceneDelegate. My question: how do I control what scene gets restored in this situation? I want my main scene to come back. Messages and Mail and Notes all do this. If you open Messages and drag a conversation out into a new window, you get a window for that conversation with a Done button in the corner that will dismiss the window. If you perform my steps above with Messages, you will relaunch to the full Messages view. Are they converting the detail view to a main view on the fly? Or is there a way to tell the system that the detail scene is secondary and should not be restored first, or that I should get asked what I want to restore via configurationForConnectingSceneSession? Or something else?

I have an iOS app that can play audio books as FairPlay DRM'd audio streams. I'm using AVContentKeySession to fetch keys and AVQueuePlayer to play. It works great on iOS, but on Catalyst (Monterey 12.3.1, M1 Max MacBook Pro) it crashes. When it happens in debug, I get a message "Too few bits left in input buffer" printed to the console, and an exception is thrown in the guts of what appears to be core media. Here's the output from [NSThread callStackSymbols] when paused on an exception breakpoint at that point: 0   ???                       0x0000000156b8cc9c 0x0 + 5749918876, 1   BRFree                    0x000000010445cf08 main + 0, 2   AudioCodecs               0x0000000157918c24 _ZL11GetPropertyPvjPjS_ + 52, 3   AudioToolboxCore          0x00000001862536a4 _ZN15ADTSAudioStream11ParseHeaderER27AudioFileStreamContinuation + 1060, 4   AudioToolboxCore          0x000000018624259c AudioFileStreamParseBytes + 412, 5   MediaToolbox              0x00000001915f7d98 FigManifoldCreateForICY + 2176, 6   MediaToolbox              0x00000001915f7718 FigManifoldCreateForICY + 512, 7   MediaToolbox              0x00000001916bbd78 FigPlayerStreamCreate + 315920, 8   MediaToolbox              0x0000000191a269a0 FigMetadataConverterCreateForQuickTimeToFromiTunes + 45888, 9   MediaToolbox              0x0000000191a4a290 FigMetadataConverterCreateForQuickTimeToFromiTunes + 191536, 10  MediaToolbox              0x0000000191a2a470 FigMetadataConverterCreateForQuickTimeToFromiTunes + 60944, 11  MediaToolbox              0x0000000191a28c34 FigMetadataConverterCreateForQuickTimeToFromiTunes + 54740, 12  MediaToolbox              0x0000000191a413b4 FigMetadataConverterCreateForQuickTimeToFromiTunes + 154964, 13  MediaToolbox              0x0000000191a2f144 FigMetadataConverterCreateForQuickTimeToFromiTunes + 80612, 14  MediaToolbox              0x00000001917cae64 FigAlternateFilterMonitorCreateForThermalNotification + 30428, 15  MediaToolbox              0x00000001917ccb44 FigAlternateFilterMonitorCreateForThermalNotification + 37820, 16  MediaToolbox              0x00000001917cb134 FigAlternateFilterMonitorCreateForThermalNotification + 31148, 17  CFNetwork                 0x0000000189937cd4 _CFHostIsDomainTopLevelForCertificatePolicy + 27728, 18  Foundation                0x0000000185ba980c __NSBLOCKOPERATION_IS_CALLING_OUT_TO_A_BLOCK__ + 24, 19  Foundation                0x0000000185ba96b4 -[NSBlockOperation main] + 104, 20  Foundation                0x0000000185ba9644 __NSOPERATION_IS_INVOKING_MAIN__ + 24, 21  Foundation                0x0000000185ba88dc -[NSOperation start] + 788, 22  Foundation                0x0000000185ba85c0 __NSOPERATIONQUEUE_IS_STARTING_AN_OPERATION__ + 24, 23  Foundation                0x0000000185ba8478 __NSOQSchedule_f + 184, 24  libdispatch.dylib         0x00000001099f60f4 _dispatch_block_async_invoke2 + 148, 25  libdispatch.dylib         0x00000001099e2394 _dispatch_client_callout + 20, 26  libdispatch.dylib         0x00000001099eb778 _dispatch_lane_serial_drain + 980, 27  libdispatch.dylib         0x00000001099ec814 _dispatch_lane_invoke + 492, 28  libdispatch.dylib         0x00000001099f9fc8 _dispatch_root_queue_drain + 408, 29  libdispatch.dylib         0x00000001099f9d3c _dispatch_worker_thread + 264, 30  libsystem_pthread.dylib   0x00000001094e1890 _pthread_start + 148, 31  libsystem_pthread.dylib   0x00000001094ebaa8 thread_start + 8 In the Debug Navigator, the top of the stack looks a little different: #0 0x0000000184bdeb3c in __cxa_throw () #1 0x000000015791941c in ACMP4AACLowComplexityDecoder::GetProperty(unsigned int, unsigned int&, void*) () #2 0x0000000157918c24 in GetProperty(void*, unsigned int, unsigned int*, void*) () #3 0x00000001862536a4 in ADTSAudioStream::ParseHeader(AudioFileStreamContinuation&) () #4 0x000000018624259c in AudioFileStreamParseBytes () #5 0x00000001915f7d98 in ___lldb_unnamed_symbol598$$MediaToolbox () What's going wrong here? Can anyone give me direction on what to fix? Or is FairPlay audio not even expected to work in Catalyst at this point?

I have been getting crash reports from users of my Mac app on Sonoma 14.0 and 14.1 when typing into an NSTextView subclass. The crash logs I have show involvement of the spell-checking system - NSTestCheckingController, NSSpellChecker, and NSCorrectionPanel. The crash is because of an exception being thrown. The throwing method is either [NSString getParagraphStart:end:contentsEnd:forRange:] or [NSTextStorage ensureAttributesAreFixedInRange:]. I have not yet reproduced the crash. I have tried modifying the reference finding process to simply link every word, via NSStringEnumerationByWords. The text view in question recognizes certain things in the entered text and adds hyperlinks to the text while the user is typing. It re-parses and re-adds the links on every key press (via overriding the didChangeText method), on a background thread. From user reports, I have learned that: The crash only occurs on macOS 14.0 and 14.1, not on previous versions The call stack always involves the spell checker, and sometimes involves adding recognized links to the text storage (the call to DispatchQueue.main.async in the code below) The crash stops happening if the user turns off the system spell checker in System Settings -> Keyboard -> Edit on an Input Source -> Correct Spelling Automatically switch The crash does not happen when there are no links in the text view. Here is the relevant code: extension NSMutableAttributedString { func batchUpdates(_ updates: () -> ()) { self.beginEditing() updates() self.endEditing() } } class MyTextView : NSTextView { func didChangeText() { super.didChangeText() findReferences() } var parseToken: CancelationToken? = nil let parseQueue = DispatchQueue(label: "com.myapp.ref_parser") private func findReferences() { guard let storage = self.textStorage else { return } self.parseToken?.requestCancel() let token = CancelationToken() self.parseToken = token let text = storage.string self.parseQueue.async { if token.cancelRequested { return } let refs = RefParser.findReferences(inText: text, cancelationToken: token) DispatchQueue.main.async { if !token.cancelRequested { storage.batchUpdates { var linkRanges: [NSRange] = [] storage.enumerateAttribute(.link, in: NSRange(location: 0, length: storage.length)) { linkValue, linkRange, stop in if let linkUrl = linkValue as? NSURL { linkRanges.append(linkRange) } } for rng in linkRanges { storage.removeAttribute(.link, range: rng) } for r in refs { storage.addAttribute(.link, value: r.url, range: r.range) } } self.verseParseToken = nil } } } } } I've filed this as FB13306015 if any engineers see this. Can anyone

I have a button in my iOS app that opens the Settings app to my app's Notification permissions section. I use UIApplicationOpenSettingsURLString for this (or UIApplicationOpenNotificationSettingsURLString on iOS 15.4 and later). On Catalyst, both of these simply open the settings screen that is auto-generated from the Settings bundle. How do I get it to open to the appropriate place in System Settings?

This is a follow up to this post about building a Control Center widget to open the app directly to a particular feature. I have it working in a sample app, but when I do the same thing in my full app I get this error: [[com.olivetree.BR-Free::com.olivetree.BR-Free.VerseWidget:com.olivetree.BR-Free.ContinueReadingPlanControl:-]] Control action: failed with error: Error Domain=ChronoKit.InteractiveWidgetActionRunner.Errors Code=1 "(null)" Google has nothing for any of that. Can anyone shed light on what it means? This is my control and its action: @available(iOS 18.0, *) struct ContinueReadingPlanControl : ControlWidget { var body: some ControlWidgetConfiguration { StaticControlConfiguration(kind: "com.olivetree.BR-Free.ContinueReadingPlanControl") { ControlWidgetButton(action: ContinueReadingPlanIntent()) { Image(systemName: "book") } } .displayName("Continue Reading Plan") } } @available(iOS 18.0, *) struct ContinueReadingPlanIntent : ControlConfigurationIntent { static let title: LocalizedStringResource = "Continue Reading Plan" static let description = IntentDescription(stringLiteral: "Continue the last-used reading plan") static let isDiscoverable = false static let opensAppWhenRun: Bool = true @MainActor func perform() async throws -> some IntentResult & OpensIntent { let strUrl = "olivetree://startplanday" UserDefaults.standard.setValue(strUrl, forKey: "StartupUrl") return .result(opensIntent: OpenURLIntent(URL(string: strUrl)!)) } } Note also that I'm pulling this from Console.app, streaming the logs from my device. I don't know of a way to debug a Control Center widget in Xcode, though this thread implies that it's possible.

I have a Catalyst app that uses popovers frequently, and I'd love to have them stay active when the app loses focus. It appears this is controlled in a native AppKit app via NSPopover.Behavior. Is this functionality exposed somewhere in Catalyst?

I've got an iOS app with a custom top toolbar view that uses a UIScrollEdgeElementContainerInteraction to achieve the iOS 26 progressive blur background. It's over top of a web view, and I've set the top edge effect style on its scroll view to .hard so the toolbar's edges are more defined. I'm noticing that the blur doesn't extend fully to the bottom edge of the toolbar, and I'm curious to know if this is a bug or expected behavior. If the latter, what exactly are the details of what's expected? What determines the bottom extent of the blur? I've got this result in a sample project on iOS 26.0. The white border is the label, and the red border is the title bar view itself. Note that the Daring Fireball logo visible inside the bounds of the bar view, and is cut off at the bottom edge of the label. This is the code from the demo app that produced the screenshot. let config = WKWebViewConfiguration() let webView = WKWebView(frame: .zero, configuration: config) self.view.addSubview(webView) webView.translatesAutoresizingMaskIntoConstraints = false webView.topAnchor.constraint(equalTo: self.view.topAnchor).isActive = true; webView.bottomAnchor.constraint(equalTo: self.view.bottomAnchor).isActive = true; webView.leftAnchor.constraint(equalTo: self.view.leftAnchor).isActive = true; webView.rightAnchor.constraint(equalTo: self.view.rightAnchor).isActive = true; webView.scrollView.topEdgeEffect.style = .hard webView.load(URLRequest(url: URL(string: "https://daringfireball.net")!)) let barView = UIView() self.view.addSubview(barView) barView.translatesAutoresizingMaskIntoConstraints = false barView.topAnchor.constraint(equalTo: self.view.topAnchor).isActive = true; barView.leftAnchor.constraint(equalTo: self.view.leftAnchor).isActive = true barView.rightAnchor.constraint(equalTo: self.view.rightAnchor).isActive = true let edgeEffect = UIScrollEdgeElementContainerInteraction() edgeEffect.scrollView = webView.scrollView edgeEffect.edge = .top barView.addInteraction(edgeEffect) barView.layer.borderColor = UIColor.red.cgColor barView.layer.borderWidth = 1 let titleLabel = UILabel() barView.addSubview(titleLabel) titleLabel.translatesAutoresizingMaskIntoConstraints = false titleLabel.leftAnchor.constraint(equalTo: barView.leftAnchor).isActive = true titleLabel.rightAnchor.constraint(equalTo: barView.rightAnchor).isActive = true titleLabel.bottomAnchor.constraint(equalTo: barView.bottomAnchor, constant: -20).isActive = true titleLabel.topAnchor.constraint(equalTo: barView.safeAreaLayoutGuide.topAnchor, constant: 8).isActive = true titleLabel.textAlignment = .center titleLabel.text = "Title Here" titleLabel.layer.borderColor = UIColor.green.cgColor titleLabel.layer.borderWidth = 1

I notice in iOS 14 beta 4, collection views show index views on their trailing edge if the data source implements indexTitlesForCollectionView - https://developer.apple.com/documentation/uikit/uicollectionviewdatasource/2851455-indextitlesforcollectionview?language=objc and indexPathForIndexTitle - https://developer.apple.com/documentation/uikit/uicollectionviewdatasource/2851456-collectionview?language=objc. But I don't see a way to control any aspect of its appearance. On UITableView this shows up as the sectionIndexColor - https://developer.apple.com/documentation/uikit/uitableview/1614915-sectionindexcolor?language=objc property. Does this property exist on UICollectionView somewhere I didn't think to look? Or is it just not there (yet)? FB8284500

UILargeContentViewerInteraction, added in iOS 13, works out of the box on the tab bar in a UITabBarController, and it's easy to set up on a custom view using the UILargeContentViewerItem properties on UIView. But how do I set it up on a UITabBar that's not connected to a UITabBarController? There don't appear to be any relevant properties on UITabBarItem. To try this, I made a sample app, added a tab bar, set up some items, set their largeContentSizeImage properties for good measure, ran the app, set text size to a large accessibility value, and long-pressed on the items, and I get no large content viewer. I also tried adding a UILargeContentViewerInteraction to the tab bar, and implemented the viewControllerForInteraction method in the delegate.

I want to add a Control Center widget for my app that will open the app to a particular feature. I'm looking at the "Open your app with a control" example here, which seems like exactly what I want: Set your control’s action to an app intent that conforms to OpenIntent to open your app when someone uses a control. Using OpenIntent allows you to take someone to a specific area of your app when a control performs its action. The example doesn't show exactly how to hook up the LaunchAppIntent to a control widget, but I'm guessing it's something like this: @available(iOS 18.0, *) struct OpenFeatureControl : ControlWidget { var body: some ControlWidgetConfiguration { StaticControlConfiguration(kind: "com.example.OpenFeature") { ControlWidgetButton(action: LaunchAppIntent()) { Image(systemName: "book") } } .displayName("Launch Feature") } } But there's one critical piece missing here: how is the target feature actually opened? My initial assumption would have been that once the app launches or resumes, there's a call to some method like continueUserActivity that has a user-info dict with some key whose value is the LaunchAppEnum. But I've put breakpoints on all those methods in my app and none of them get called (I'm using UIKit scene lifecycle). I also tried a regular AppIntent with a perform method that talks to my app directly: @available(iOS 18.0, *) struct OpenFeatureIntent : AppIntent { static let title: LocalizedStringResource = "Open My Feature" static let opensAppWhenRun: Bool = true init() {} func perform() async throws -> some IntentResult { //MAIN_APP is defined in Active Compilation Conditions in build settings #if MAIN_APP let url = URL(string: "myapp://openfeature")! UrlHandler.instance().handle(url) #endif return .result() } } But when run, this simply does nothing. Launching an app directly to a particular view or feature seems like a common use-case for control widgets, and there are apps doing it, but I can't find an example of how it's supposed to work. And the docs are really not helpful. Can anyone provide the missing piece here? What's the expected plumbing in an OpenIntent that actually launches particular UI in the app?

I have an app that uses UITextView for some text editing. I have some custom operations I can do on the text that I want to be able to undo, and I'm representing those operations in a way that plugs into NSUndoManager nicely. For example, if I have a button that appends an emoji to the text, it looks something like this: func addEmoji() { let inserting = NSAttributedString(string: "😀") self.textStorage.append(inserting) let len = inserting.length let range = NSRange(location: self.textStorage.length - len, length: len) self.undoManager?.registerUndo(withTarget: self, handler: { view in view.textStorage.deleteCharacters(in: range) } } My goal is something like this: Type some text Press the emoji button to add the emoji Trigger undo (via gesture or keyboard shortcut) and the emoji is removed Trigger undo again and the typing from step 1 is reversed If I just type and then trigger undo, the typing is reversed as you'd expect. And if I just add the emoji and trigger undo, the emoji is removed. But if I do the sequence above, step 3 works but step 4 doesn't. The emoji is removed but the typing isn't reversed. Notably, if step 3 only changes attributes of the text, like applying a strikethrough to a selection, then the full undo chain works. I can type, apply strikethrough, undo strikethrough, and undo typing. It's almost as if changing the text invalidates the undo manager's previous operations? How do I insert my own changes into UITextView's NSUndoManager without invalidating its chain of other operations?

I work on an iOS app that displays images that often contain text, and I'm adding support for ImageAnalysisInteraction as described in this WWDC 2022 session. I have gotten as far as making the interaction show up and being able to select text and get the system selection menu, and even add my own action to the menu via the buildMenuWithBuilder API. But what I really want to do with my custom action is get the selected text and do a custom lookup-like thing to check the text against other content in my app. So how do I get the selected text from an ImageAnalysisInteraction on a UIImageView? The docs show methods to check if there is selected text, but I want to know what the text is.

I'm experimenting with downloading an audio file of spoken content, using the Speech framework to transcribe it, then using FoundationModels to clean up the formatting to add paragraph breaks and such. I have this code to do that cleanup: private func cleanupText(_ text: String) async throws -> String? { print("Cleaning up text of length \(text.count)...") let session = LanguageModelSession(instructions: "The content you read is a transcription of a speech. Separate it into paragraphs by adding newlines. Do not modify the content - only add newlines.") let response = try await session.respond(to: .init(text), generating: String.self) return response.content } The content length is about 29,000 characters. And I get this error: InferenceError::inferenceFailed::Failed to run inference: Context length of 4096 was exceeded during singleExtend.. Is 4096 a reference to a max input length? Or is this a bug? This is running on an M1 iPad Air, with iPadOS 26 Seed 1.

In the WWDC 2025 session "Build a UIKit app with the with the new design", at the 23:22 mark, the presenter says: And finally, when you no longer need the glass on screen animate it out by setting the effect to nil. The video shows a UIVisualEffectView whose effect is set to a UIGlassEffect animating away as its effect is set to nil. But when I do this in my app (or a sample app), setting effect to nil does not remove the glass appearance. Is this expected? Is the video out of date? Or is this a bug?