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AVAudioSession dropping wired USBAudio source
My app inputs electrical waveforms from an IV485B39 2 channel USB device using an AVAudioSession. Before attempting to acquire data I make sure the input device is available as follows: AVAudiosSession *audioSession = [AVAudioSession sharedInstance]; [audioSession setCategory :AVAudioSessionCategoryRecord error:&err]; NSArray *inputs = [audioSession availableInputs]; I have been using this code for about 10 years. My app is scriptable so a user can acquire data from the IV485B29 multiple times with various parameter settings (sampling rates and sample duration). Recently the scripts have been failing to complete and what I have notice that when it fails the list of available inputs is missing the USBAudio input. While debugging I have noticed that when working properly the list of inputs includes both the internal microphone as well as the USBAudio device as shown below. VIB_TimeSeriesViewController:***Available inputs = ( "<AVAudioSessionPortDescription: 0x11584c7d0, type = MicrophoneBuiltIn; name = iPad Microphone; UID = Built-In Microphone; selectedDataSource = Front>", "<AVAudioSessionPortDescription: 0x11584cae0, type = USBAudio; name = 485B39 200095708064650803073200616; UID = AppleUSBAudioEngine:Digiducer.com :485B39 200095708064650803073200616:000957 200095708064650803073200616:1; selectedDataSource = (null)>" ) But when it fails I only see the built in microphone. VIB_TimeSeriesViewController:***Available inputs = ( "<AVAudioSessionPortDescription: 0x11584cef0, type = MicrophoneBuiltIn; name = iPad Microphone; UID = Built-In Microphone; selectedDataSource = Front>" ) If I only see the built in microphone I immediately repeat the three lines of code and most of the "inputs" contains both the internal microphone and the USBAudioDevice AVAudiosSession *audioSession = [AVAudioSession sharedInstance]; [audioSession setCategory :AVAudioSessionCategoryRecord error:&err]; NSArray *inputs = [audioSession availableInputs]; This fix always works on my M2 iPadPro and my iPhone 14 but some of my customers have older devices and even with 3 tries they still get faults about 1 in 10 tries. I rolled back my code to a released version from about 12 months ago where I know we never had this problem and compiled it against the current libraries and the problem still exists. I assume this is a problem caused by a change in the AVAudioSession framework libraries. I need to find a way to work around the issue or get the library fixed.
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156
May ’25
Custom, Markdown autocapitalizationType.
Hi, I've got an app that displays markdown in UITextView / NSTextView. I would like it to behave like Notes app does, that is if user types the line start modifier, e.g: "# " or "> " I would like the keyboard to show a capitalized letters. I've tried looking into overriding insertText - and it breaks the predictive text (can not insert white space). I've tried implementing UITextInputTokenizer but no luck either. Like I said, I see the Notes app does it perfectly, so maybe I'm missing something obvious or there is a way to do it without interrupting the auto-correction and predictive text. Ideally same thing can be applied to the NSTextView as the app support both platforms.
Topic: UI Frameworks SubTopic: UIKit Tags:
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278
May ’25
The NSTextViewDelegate method textViewDidChangeSelection(:) will not fire, while all other text view delegate methods do.
I am trying to implement the NSTextViewDelegate function textViewDidChangeSelection(_ notification: Notification). My text view's delegate is the Coordinator of my NSViewRepresentable. I've found that this delegate function never fires, but any other delegate function that I implement, as long as it doesn't take a Notification as an argument, does fire (e.g., textView(:willChangeSelectionFromCharacterRange:toCharacterRange:), fires and is called on the delegate exactly when it should be). For context, I've verified all of the below: textView.isSelectable = true textView.isEditable = true textView.delegate === my coordinator I can call textViewDidChangeSelection(:) directly on the delegate without issue. I can select and edit text without issues. I.e., the selections are being set correctly. But the delegate method is never called when they are. I am able to add the intended delegate as an observer for the selector textViewDidChangeSelection via NotificationCenter. If I do this, the function executes when it should, but fires for every text view in my view hierarchy, which can number in the hundreds. I'm using an NSLayoutManager, so I figure this should only fire once. I've added a check within my code: func textViewDidChangeSelection(_ notification: Notification) { guard let textView = notification.object as? NSTextView, textView === layoutManager.firstTextView else { return } // Any code I want to execute... } But the above guard check lets through every notification, so, no matter what, my closure executes hundreds of times if I have hundreds of text views, all of them being sent by textView === layoutManager.firstTextView, but once for each and every text view managed by that layoutManager. Does anyone know why this method isn't ever called on the delegate, while seemingly all other delegate methods are? I could go the NotificationCenter route, but I'd love to know why this won't execute as a delegate method when documentation says that it should, and I don't want to have to implement a counter to make sure my code only executes once per selection update. And for more reasons than that, implementing via delegate method is preferable to using notifications for my use case. Thanks for any help!
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270
May ’25
CATiledLayer flashes and re-draws entirely when re-drawing a single tile
I have filed a bug report for this (FB17734946), but I'm posting it here verbatim in case others have the same issue and in hopes of getting attention from an Apple engineer sooner. When calling setNeedsDisplayInRect on a CATiledLayer - or a UIView whose backing layer is CATiledLayer - one would expect to re-draw only a region identified by the rect passed to the method. This is even written in the documentation for the class: "Regions of the layer may be invalidated using the setNeedsDisplayInRect: method however the update will be asynchronous. While the next display update will most likely not contain the updated content, a future update will." However, upon calling this method, CATiledLayer redraws whole contents instead of just the tile at the specified rect, and it flashes when doing so. It behaves exactly the same as if one had called setNeedsDisplay without passing any rect; all contents are cleared and re-drawn again. I'm 100% sure I've passed in the correct rect of the exact tile that I need to redraw. I have even tried passing much smaller rects, but still the same. (And yes, the rect I've passed accounts for the current level of detail.) I have found this GitHub repo https://github.com/frankus/NetPhotoScroller, which based on discussion from here https://forums.macrumors.com/threads/catiledlayer-blanks-out-tiles-when-redrawing.1333948/ aims at solving these issues by using two private methods on CATiledLayer class: (void)setNeedsDisplayInRect:(CGRect)r levelOfDetail:(int)level; (BOOL)canDrawRect:(CGRect)rect levelOfDetail:(int)level; I have explored the repo in detail, however I wasn't able to test exactly this code from the GitHub repo. I have tried using those two private methods myself (through an Objective-C class that defines the methods in the header file and then a swift class which inherits it), but I couldn't solve the issue; the flashing and the full re-draw is still there. After doing a lot of research, the conclusion seems to be that one cannot use CATiledLayer with contents that are downloaded remotely, on demand, as tiles are being requested. I have, however, found one interesting thing which seems to work so far: before calling setNeedsDisplayInRect (or just setNeedsDisplay, as they behave the same for CATiledLayer in my testing), cache the current layer's contents, and after calling setNeedsDisplay (or setNeedsDisplayInRect), restore the contents back to the layer. This prevents flashing and preserves any tiles that were drawn at the time of the re-draw. let c = tiledLayer.contents tiledLayer.setNeedsDisplay(tileRect) tiledLayer.contents = c However! Docs clearly state the warning: Do not attempt to directly modify the contents property of a CATiledLayer object. Doing so disables the ability of a tiled layer to asynchronously provide tiled content, effectively turning the layer into a regular CALayer object. I believe this message implies modifying the contents property with some raw content, like image data, and that it may be safe to re-apply the existing contents (which are in my testing of type CAImageProvider) -- but I can't rely on an implementation detail in my production app. I have tested this and confirmed that the bug appears on: iPhone 14 Pro, iOS 18.5 iPhone 13 Pro, iOS 17.5.1 iPhone 5s, iOS 15.8.3 iPad Pro 1st gen, iPadOS 18.4.1 a couple simulator versions I can also confirm that the fix (to re-apply contents property) is also working properly on all these versions. Is this expected behavior, that tiled layer redraws itself entirely instead of redrawing specific tiles? Is it safe to modify contents of a CATiledLayer by re-applying the existing contents? If not, is there an alternative to avoid flashing?
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212
May ’25
Is it safe to access NSPrinter.printerNames on a background thread?
I'm working on a macOS application that needs to query the list of available printers using NSPrinter.printerNames. For performance reasons, I'd like to perform this operation on a background thread. However, since NSPrinter is part of AppKit, and AppKit is generally not thread-safe unless explicitly stated, I want to confirm: Is it safe to call NSPrinter.printerNames from a background thread? I couldn’t find explicit guidance in the documentation regarding the thread-safety of printerNames, so any clarification or best practices would be appreciated. Thanks in advance! Note: I tested this api on a background thread in code and it did not give any error.
Topic: UI Frameworks SubTopic: AppKit Tags:
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146
May ’25
Live activity widget not updated locally after server update
I am using live activity in my app. Functionality is start, update & end events are started from the server. There is one interaction button added using app intent in live activity widget. That button needs to update widget ui locally using activity kit. Issue is when os receives first start event push then update ui works fine and reflecting on live activity widget but when update notification receives by os after 1 mins then action button stops updating the ui locally. Can anyone please add some suggestions to fix this.
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163
May ’25
NSTextLists not rendered when NSTextContentStorageDelegate textContentStorage (_:, textParagraphWith:) is implemented
I have a UITextView that contains paragraphs with text bullet lists (via NSTextList). I also implement NSTextContentStorageDelegate.textContentStorage(_:, textParagraphWith:) in order to apply some custom attributes to the text without affecting the underlying attributed text. My implementation returns a new NSParagraph that modifies the foreground color of the text. I based this on the example in the WWDC 21 session "Meet Text Kit 2". UITextView stops rendering the bullets when I implement the delegate function and return a custom paragraph. Why? func textContentStorage(_ textContentStorage: NSTextContentStorage, textParagraphWith range: NSRange) -> NSTextParagraph? { guard let originalText = textContentStorage.textStorage?.attributedSubstring(from: range) else { return nil } let updatedText = NSMutableAttributedString(attributedString: originalText) updatedText.addAttribute(.foregroundColor, value: UIColor.green, range: NSRange(location: 0, length: updatedText.length)) let paragraph = NSTextParagraph(attributedString: updatedText) // Verify that the text still contains NSTextList if let paragraphStyle = paragraph.attributedString.attribute(.paragraphStyle, at: 0, effectiveRange: nil) as? NSParagraphStyle { assert(!paragraphStyle.textLists.isEmpty) } else { assertionFailure("Paragraph has lost its text lists") } return paragraph }
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494
May ’25
Alert structure and playing sound
Hello, I'm working on an SwiftUI iOS app that shows a list of timers. When the timer is up then I pop up an alert struct. The user hits "ok" to dismiss the alert. I am trying to include an alarm sound using AVFoundation. I can get the sounds to play if I change the code to play when a button clicks so I believe I have the url path correct. But I really want it to play during the alert pop up. I have not been able to find examples where this is done using an alert so I suspect I need a custom view but thought I'd try the alert route first. Anyone try this before? @State var audioPlayer: AVAudioPlayer? .alert(isPresented: $showAlarmAlert) { playSound() -- Calls AVFoundation return Alert(title: Text("Time's Up!")) } func playSound() { let alertSoundPath = Bundle.main.url(forResource: "classicAlarm", withExtension: "mp3")! do { audioPlayer = try AVAudioPlayer(contentsOf: alertSoundPath) audioPlayer?.play() } catch { appData.logger.debug("Error playing sound: \(alertSoundPath)") } }
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179
Jun ’25
openURL:options:completionHandler: Not Opening tel:// Link on iPad with Cellular Data
We are using openURL:options:completionHandler: to open a tel:// number in the dialer to place a call. This works on iPhones and WiFi-only iPads (tested with a iPad Mini 6th Gen), but it is failing to open on an iPad 8th Gen (WiFi + Cellular) running iPadOS 18.5 being used by a customer. Prior to updating the iPad to iPadOS 18, the call worked on iPadOS 15.2 and opened the call in FaceTime as expected. Despite not opening the dialer in iPadOS 18, the completionHandler returns the success parameter as true. canOpenUrl also returns true. We created a small test application that reproduces the issue using the code snippet below in a new application, with the tel schema added to the info.plist Queried URL Schemes. We are currently using Xcode 16.3. Test Steps: Create a new blank application and replace ContentView.swift with the code snippet below Run the test app on a physical iPad 8th Gen (WiFi + Cellular) Tap the "place a test call" button Expected Results: The user is prompted to call the number and is taken to FaceTime to attempt the call. The user may then receive an alert telling them an iPhone must be paired if not already. Alternatively: return success = false in the completionHandler. Actual Results: No action occurs that is visible to the user, and the completionHandler returns success = true. Separately, we should be able to have some method of checking if the device can actually complete a call, i.e. if an iPhone is paired, so that we can correctly show or hide a phone icon in the app based on if the user can place a call. canOpenUrl returns true even if there is not a device paired and the call cannot actually be placed, and there doesn't seem to be a proper method for making that check. Code Snippet: import SwiftUI struct ContentView: View { @State private var showAlert = false var body: some View { VStack { Image(systemName: "globe") .imageScale(.large) .foregroundStyle(.tint) Text("Hello, world!") Button("Place a test call") { if let url = URL(string: "tel://5555554567") { UIApplication.shared.open(url) { success in if success { print("Call initiated successfully.") } else { showAlert = true } } } } } .padding() .alert("Call Failed", isPresented: $showAlert) { Button("OK") { showAlert = false } } message: { Text("The call could not be initiated.") } } } #Preview { ContentView() }
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247
Jun ’25
Conditionally Adding and Deleting a Row in a UITableView
Hello! I wanted to see if someone with more UIKit experience than me can help me out on guiding me in the right direction for conditionally adding and deleting a row in a UITableView. What I Want to Accomplish I have a tip slider with percentages (0% - 20%) with a custom option on the end. I'm wanting to, when the custom option is tapped, bring up a row immediately below there and have a UITextField. When another option, let's say 10%, is tapped, I want the text field row to go away. Can someone explain to me how this would work? And if so, provide an example? Thank you!
Topic: UI Frameworks SubTopic: UIKit Tags:
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134
Jun ’25
macOS Sequoia/Xcode 16.2 - Catalyst App Missing Tab Bar
My Objective-C Catalyst app when built with Xcode 16.x/iOS 18 does not have a visible Tab Bar when run on Sequoia. App starts up in first tab, but there is no way to access other tabs. The same app when run on macOS Sonoma (or macOS Catalina) has a normal Tab Bar. The app has an initial View UITabBarController with 3 tabs. The main tab is a UiSplitViewController. Minimum macOS deployment 10.5. If app is built on Sonoma with Xcode 15.x/iOS 17 the Tab Bar is normal on macOS Sonoma, Sequoia, and Catalina. I've tried without success: if (@available(macCatalyst 18.0, *)) { self.tabBarController.tabBarHidden = false; } else { // Fallback on earlier versions } I wonder if this console log message has anything to do with the problem: CLIENT OF UIKIT REQUIRES UPDATE: This process does not adopt UIScene lifecycle. This will become an assert in a future version.
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Jun ’25
chartXAxis AxisMark consisting of Month:Year
I have a Chart displaying Counts per Date over 2-3 years. I'd like to have the XAxis mark consist of MM-yy or even MM/nyy. Is this possible? OK, just saw AxisValueLabel(format: .dateTime.month().year()) which gives e.g. Mar 2024. This is good. Better might be Mar 24 (maybe a Y3K problem ;-) or even better Mar. OR Mar 24. 2024 Or best increment the year when it changes. Are any of these alternate formats possible? Thanks, David PS, my current .chartXAxis code .chartXAxis { AxisMarks(values: .stride(by: .month, count: 3)) { value in if value.as(Date.self) != nil { AxisValueLabel(format: .dateTime.month().year()) AxisGridLine() AxisTick() } } }
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Jun ’25
How can I make a new item from within a navigationlink?
Sorry if this is too basic, but I really can't figure out how to make this work. I am trying to make a journal app and I want to have a button that creates a new journalentry and then loads it. This code snippet (I removed irrelevant bits) shows how I'm trying to go about it. Basically, the newEntryButtons should launch a JournalPromptRoute for one of the different options: that's the method argument. But putting .createNewEntry() inside the argument means that new entries are being constantly created. I want the system to create a new entry once on the button press and then go to it from the navigationDestination area. Can anyone please explain to me how this is supposed to work? I believe the code snippet is detailed enough to get the point across but please let me know if you need more info. case library case blank(entry: Entry) case mystery case summary(entry: Entry) case entry(entry: Entry) } struct JournalHome: View { @ObservedObject var viewModel: JournalViewModel var mainContent: some View { ScrollView { newEntryButtons LazyVStack { ForEach(filteredEntries) { entry in NavigationLink( value: JournalPromptRoute.entry(entry: entry) ) { JournalCard(entry) } } } } } var body: some View { NavigationStack(path: $path) { mainContent .navigationDestination(for: JournalPromptRoute.self) { route in switch route { case .blank(let entry): JournalEntryView( entry: entry, index: 0, viewModel: viewModel ) } } } } var newEntryButtons: some View { ScrollView(.horizontal) { HStack(spacing: 15) { EntryButton( description: "Add blank entry", method: JournalPromptRoute.blank(entry: viewModel.createNewEntry()), viewModel: viewModel, path: $path ) EntryButton( description: "Select a Journey", method: JournalPromptRoute.library, viewModel: viewModel, path: $path ) EntryButton( description: "Let the Journey find you", method: JournalPromptRoute.mystery, viewModel: viewModel, path: $path ) } } } }
Topic: UI Frameworks SubTopic: SwiftUI
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Jun ’25
popover no longer anchoring
My old UIKit popovers are no longer anchoring to their sourceView and sourceRect. Started happening while testing on IPadOS 18.5 after updating to Xcode 16.4. Has anyone else had to fix this problem? Popovers now slide up from the bottom to the center of the screen.
Topic: UI Frameworks SubTopic: UIKit
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79
Jun ’25
SwiftUI internal crash when interacting with long list quickly
Hello! We encountered a very intermittent crash with our application starting with devices running iOS 18.4. We have a screen that can display a long list of products in 2 states (expanded or collapsed) based off of a boolean if the user has interacted with that product yet. With this list, we very intermittently encounter a crash when we scroll like crazy up and down the list search the list quickly (search is performed each character change and list is filtered) Our project has iOS 17.0 as a minimum deployment target, and is Swift 6 enabled. Again, this started happening only with iOS 18.4, and is still visible (handful of occurrences each week). The crash report seems to be very internal to SwiftUI/Obj-c runtime. 5895AC17-6886-4070-BC80-8912E8394BDB.crash Any insights would be greatly appreciated!
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204
Jun ’25
PKPass Framework
I am trying to work with the data inside the barcode string in shared PKPass. The documentation shows that is should look for @property (nonatomic, readonly, nullable) PKBarcode *primaryBarcode; I have tried to use it like this guard let code = pass.primaryBarcode?.message else { return } I get a constant message that PKPass has no member primaryBarcode The PKPass.h file in my IOS SDK does not seem to include the @property primaryBarcode or @property barcode. I am running Xcode 16.4 (16F6) and my app target is 17.6 + Is there a restriction on this property? I cannot find an SDK later than mine - the App Store does not offer one. I am unsure of this is a public or private issue - does anyone know? Thanks for reading this. Max
Topic: UI Frameworks SubTopic: SwiftUI
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102
Jun ’25
App displays wrong localized image
I have an image in the xcassets file which is localized for different languages. When setting App language to Traditional Chinese, it always displays the Simplified Chinese image. This happens on latest iOS 18.5 system, but not on a lower system version. The feedback assistant ID is FB17663546
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114
Jun ’25
AVAudioSession dropping wired USBAudio source
My app inputs electrical waveforms from an IV485B39 2 channel USB device using an AVAudioSession. Before attempting to acquire data I make sure the input device is available as follows: AVAudiosSession *audioSession = [AVAudioSession sharedInstance]; [audioSession setCategory :AVAudioSessionCategoryRecord error:&err]; NSArray *inputs = [audioSession availableInputs]; I have been using this code for about 10 years. My app is scriptable so a user can acquire data from the IV485B29 multiple times with various parameter settings (sampling rates and sample duration). Recently the scripts have been failing to complete and what I have notice that when it fails the list of available inputs is missing the USBAudio input. While debugging I have noticed that when working properly the list of inputs includes both the internal microphone as well as the USBAudio device as shown below. VIB_TimeSeriesViewController:***Available inputs = ( "<AVAudioSessionPortDescription: 0x11584c7d0, type = MicrophoneBuiltIn; name = iPad Microphone; UID = Built-In Microphone; selectedDataSource = Front>", "<AVAudioSessionPortDescription: 0x11584cae0, type = USBAudio; name = 485B39 200095708064650803073200616; UID = AppleUSBAudioEngine:Digiducer.com :485B39 200095708064650803073200616:000957 200095708064650803073200616:1; selectedDataSource = (null)>" ) But when it fails I only see the built in microphone. VIB_TimeSeriesViewController:***Available inputs = ( "<AVAudioSessionPortDescription: 0x11584cef0, type = MicrophoneBuiltIn; name = iPad Microphone; UID = Built-In Microphone; selectedDataSource = Front>" ) If I only see the built in microphone I immediately repeat the three lines of code and most of the "inputs" contains both the internal microphone and the USBAudioDevice AVAudiosSession *audioSession = [AVAudioSession sharedInstance]; [audioSession setCategory :AVAudioSessionCategoryRecord error:&err]; NSArray *inputs = [audioSession availableInputs]; This fix always works on my M2 iPadPro and my iPhone 14 but some of my customers have older devices and even with 3 tries they still get faults about 1 in 10 tries. I rolled back my code to a released version from about 12 months ago where I know we never had this problem and compiled it against the current libraries and the problem still exists. I assume this is a problem caused by a change in the AVAudioSession framework libraries. I need to find a way to work around the issue or get the library fixed.
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156
Activity
May ’25
Custom, Markdown autocapitalizationType.
Hi, I've got an app that displays markdown in UITextView / NSTextView. I would like it to behave like Notes app does, that is if user types the line start modifier, e.g: "# " or "> " I would like the keyboard to show a capitalized letters. I've tried looking into overriding insertText - and it breaks the predictive text (can not insert white space). I've tried implementing UITextInputTokenizer but no luck either. Like I said, I see the Notes app does it perfectly, so maybe I'm missing something obvious or there is a way to do it without interrupting the auto-correction and predictive text. Ideally same thing can be applied to the NSTextView as the app support both platforms.
Topic: UI Frameworks SubTopic: UIKit Tags:
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278
Activity
May ’25
The NSTextViewDelegate method textViewDidChangeSelection(:) will not fire, while all other text view delegate methods do.
I am trying to implement the NSTextViewDelegate function textViewDidChangeSelection(_ notification: Notification). My text view's delegate is the Coordinator of my NSViewRepresentable. I've found that this delegate function never fires, but any other delegate function that I implement, as long as it doesn't take a Notification as an argument, does fire (e.g., textView(:willChangeSelectionFromCharacterRange:toCharacterRange:), fires and is called on the delegate exactly when it should be). For context, I've verified all of the below: textView.isSelectable = true textView.isEditable = true textView.delegate === my coordinator I can call textViewDidChangeSelection(:) directly on the delegate without issue. I can select and edit text without issues. I.e., the selections are being set correctly. But the delegate method is never called when they are. I am able to add the intended delegate as an observer for the selector textViewDidChangeSelection via NotificationCenter. If I do this, the function executes when it should, but fires for every text view in my view hierarchy, which can number in the hundreds. I'm using an NSLayoutManager, so I figure this should only fire once. I've added a check within my code: func textViewDidChangeSelection(_ notification: Notification) { guard let textView = notification.object as? NSTextView, textView === layoutManager.firstTextView else { return } // Any code I want to execute... } But the above guard check lets through every notification, so, no matter what, my closure executes hundreds of times if I have hundreds of text views, all of them being sent by textView === layoutManager.firstTextView, but once for each and every text view managed by that layoutManager. Does anyone know why this method isn't ever called on the delegate, while seemingly all other delegate methods are? I could go the NotificationCenter route, but I'd love to know why this won't execute as a delegate method when documentation says that it should, and I don't want to have to implement a counter to make sure my code only executes once per selection update. And for more reasons than that, implementing via delegate method is preferable to using notifications for my use case. Thanks for any help!
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270
Activity
May ’25
CATiledLayer flashes and re-draws entirely when re-drawing a single tile
I have filed a bug report for this (FB17734946), but I'm posting it here verbatim in case others have the same issue and in hopes of getting attention from an Apple engineer sooner. When calling setNeedsDisplayInRect on a CATiledLayer - or a UIView whose backing layer is CATiledLayer - one would expect to re-draw only a region identified by the rect passed to the method. This is even written in the documentation for the class: "Regions of the layer may be invalidated using the setNeedsDisplayInRect: method however the update will be asynchronous. While the next display update will most likely not contain the updated content, a future update will." However, upon calling this method, CATiledLayer redraws whole contents instead of just the tile at the specified rect, and it flashes when doing so. It behaves exactly the same as if one had called setNeedsDisplay without passing any rect; all contents are cleared and re-drawn again. I'm 100% sure I've passed in the correct rect of the exact tile that I need to redraw. I have even tried passing much smaller rects, but still the same. (And yes, the rect I've passed accounts for the current level of detail.) I have found this GitHub repo https://github.com/frankus/NetPhotoScroller, which based on discussion from here https://forums.macrumors.com/threads/catiledlayer-blanks-out-tiles-when-redrawing.1333948/ aims at solving these issues by using two private methods on CATiledLayer class: (void)setNeedsDisplayInRect:(CGRect)r levelOfDetail:(int)level; (BOOL)canDrawRect:(CGRect)rect levelOfDetail:(int)level; I have explored the repo in detail, however I wasn't able to test exactly this code from the GitHub repo. I have tried using those two private methods myself (through an Objective-C class that defines the methods in the header file and then a swift class which inherits it), but I couldn't solve the issue; the flashing and the full re-draw is still there. After doing a lot of research, the conclusion seems to be that one cannot use CATiledLayer with contents that are downloaded remotely, on demand, as tiles are being requested. I have, however, found one interesting thing which seems to work so far: before calling setNeedsDisplayInRect (or just setNeedsDisplay, as they behave the same for CATiledLayer in my testing), cache the current layer's contents, and after calling setNeedsDisplay (or setNeedsDisplayInRect), restore the contents back to the layer. This prevents flashing and preserves any tiles that were drawn at the time of the re-draw. let c = tiledLayer.contents tiledLayer.setNeedsDisplay(tileRect) tiledLayer.contents = c However! Docs clearly state the warning: Do not attempt to directly modify the contents property of a CATiledLayer object. Doing so disables the ability of a tiled layer to asynchronously provide tiled content, effectively turning the layer into a regular CALayer object. I believe this message implies modifying the contents property with some raw content, like image data, and that it may be safe to re-apply the existing contents (which are in my testing of type CAImageProvider) -- but I can't rely on an implementation detail in my production app. I have tested this and confirmed that the bug appears on: iPhone 14 Pro, iOS 18.5 iPhone 13 Pro, iOS 17.5.1 iPhone 5s, iOS 15.8.3 iPad Pro 1st gen, iPadOS 18.4.1 a couple simulator versions I can also confirm that the fix (to re-apply contents property) is also working properly on all these versions. Is this expected behavior, that tiled layer redraws itself entirely instead of redrawing specific tiles? Is it safe to modify contents of a CATiledLayer by re-applying the existing contents? If not, is there an alternative to avoid flashing?
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3
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212
Activity
May ’25
Is it safe to access NSPrinter.printerNames on a background thread?
I'm working on a macOS application that needs to query the list of available printers using NSPrinter.printerNames. For performance reasons, I'd like to perform this operation on a background thread. However, since NSPrinter is part of AppKit, and AppKit is generally not thread-safe unless explicitly stated, I want to confirm: Is it safe to call NSPrinter.printerNames from a background thread? I couldn’t find explicit guidance in the documentation regarding the thread-safety of printerNames, so any clarification or best practices would be appreciated. Thanks in advance! Note: I tested this api on a background thread in code and it did not give any error.
Topic: UI Frameworks SubTopic: AppKit Tags:
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146
Activity
May ’25
Live activity widget not updated locally after server update
I am using live activity in my app. Functionality is start, update & end events are started from the server. There is one interaction button added using app intent in live activity widget. That button needs to update widget ui locally using activity kit. Issue is when os receives first start event push then update ui works fine and reflecting on live activity widget but when update notification receives by os after 1 mins then action button stops updating the ui locally. Can anyone please add some suggestions to fix this.
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163
Activity
May ’25
NSTextLists not rendered when NSTextContentStorageDelegate textContentStorage (_:, textParagraphWith:) is implemented
I have a UITextView that contains paragraphs with text bullet lists (via NSTextList). I also implement NSTextContentStorageDelegate.textContentStorage(_:, textParagraphWith:) in order to apply some custom attributes to the text without affecting the underlying attributed text. My implementation returns a new NSParagraph that modifies the foreground color of the text. I based this on the example in the WWDC 21 session "Meet Text Kit 2". UITextView stops rendering the bullets when I implement the delegate function and return a custom paragraph. Why? func textContentStorage(_ textContentStorage: NSTextContentStorage, textParagraphWith range: NSRange) -> NSTextParagraph? { guard let originalText = textContentStorage.textStorage?.attributedSubstring(from: range) else { return nil } let updatedText = NSMutableAttributedString(attributedString: originalText) updatedText.addAttribute(.foregroundColor, value: UIColor.green, range: NSRange(location: 0, length: updatedText.length)) let paragraph = NSTextParagraph(attributedString: updatedText) // Verify that the text still contains NSTextList if let paragraphStyle = paragraph.attributedString.attribute(.paragraphStyle, at: 0, effectiveRange: nil) as? NSParagraphStyle { assert(!paragraphStyle.textLists.isEmpty) } else { assertionFailure("Paragraph has lost its text lists") } return paragraph }
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494
Activity
May ’25
Alert structure and playing sound
Hello, I'm working on an SwiftUI iOS app that shows a list of timers. When the timer is up then I pop up an alert struct. The user hits "ok" to dismiss the alert. I am trying to include an alarm sound using AVFoundation. I can get the sounds to play if I change the code to play when a button clicks so I believe I have the url path correct. But I really want it to play during the alert pop up. I have not been able to find examples where this is done using an alert so I suspect I need a custom view but thought I'd try the alert route first. Anyone try this before? @State var audioPlayer: AVAudioPlayer? .alert(isPresented: $showAlarmAlert) { playSound() -- Calls AVFoundation return Alert(title: Text("Time's Up!")) } func playSound() { let alertSoundPath = Bundle.main.url(forResource: "classicAlarm", withExtension: "mp3")! do { audioPlayer = try AVAudioPlayer(contentsOf: alertSoundPath) audioPlayer?.play() } catch { appData.logger.debug("Error playing sound: \(alertSoundPath)") } }
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4
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179
Activity
Jun ’25
openURL:options:completionHandler: Not Opening tel:// Link on iPad with Cellular Data
We are using openURL:options:completionHandler: to open a tel:// number in the dialer to place a call. This works on iPhones and WiFi-only iPads (tested with a iPad Mini 6th Gen), but it is failing to open on an iPad 8th Gen (WiFi + Cellular) running iPadOS 18.5 being used by a customer. Prior to updating the iPad to iPadOS 18, the call worked on iPadOS 15.2 and opened the call in FaceTime as expected. Despite not opening the dialer in iPadOS 18, the completionHandler returns the success parameter as true. canOpenUrl also returns true. We created a small test application that reproduces the issue using the code snippet below in a new application, with the tel schema added to the info.plist Queried URL Schemes. We are currently using Xcode 16.3. Test Steps: Create a new blank application and replace ContentView.swift with the code snippet below Run the test app on a physical iPad 8th Gen (WiFi + Cellular) Tap the "place a test call" button Expected Results: The user is prompted to call the number and is taken to FaceTime to attempt the call. The user may then receive an alert telling them an iPhone must be paired if not already. Alternatively: return success = false in the completionHandler. Actual Results: No action occurs that is visible to the user, and the completionHandler returns success = true. Separately, we should be able to have some method of checking if the device can actually complete a call, i.e. if an iPhone is paired, so that we can correctly show or hide a phone icon in the app based on if the user can place a call. canOpenUrl returns true even if there is not a device paired and the call cannot actually be placed, and there doesn't seem to be a proper method for making that check. Code Snippet: import SwiftUI struct ContentView: View { @State private var showAlert = false var body: some View { VStack { Image(systemName: "globe") .imageScale(.large) .foregroundStyle(.tint) Text("Hello, world!") Button("Place a test call") { if let url = URL(string: "tel://5555554567") { UIApplication.shared.open(url) { success in if success { print("Call initiated successfully.") } else { showAlert = true } } } } } .padding() .alert("Call Failed", isPresented: $showAlert) { Button("OK") { showAlert = false } } message: { Text("The call could not be initiated.") } } } #Preview { ContentView() }
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247
Activity
Jun ’25
Conditionally Adding and Deleting a Row in a UITableView
Hello! I wanted to see if someone with more UIKit experience than me can help me out on guiding me in the right direction for conditionally adding and deleting a row in a UITableView. What I Want to Accomplish I have a tip slider with percentages (0% - 20%) with a custom option on the end. I'm wanting to, when the custom option is tapped, bring up a row immediately below there and have a UITextField. When another option, let's say 10%, is tapped, I want the text field row to go away. Can someone explain to me how this would work? And if so, provide an example? Thank you!
Topic: UI Frameworks SubTopic: UIKit Tags:
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3
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134
Activity
Jun ’25
macOS Sequoia/Xcode 16.2 - Catalyst App Missing Tab Bar
My Objective-C Catalyst app when built with Xcode 16.x/iOS 18 does not have a visible Tab Bar when run on Sequoia. App starts up in first tab, but there is no way to access other tabs. The same app when run on macOS Sonoma (or macOS Catalina) has a normal Tab Bar. The app has an initial View UITabBarController with 3 tabs. The main tab is a UiSplitViewController. Minimum macOS deployment 10.5. If app is built on Sonoma with Xcode 15.x/iOS 17 the Tab Bar is normal on macOS Sonoma, Sequoia, and Catalina. I've tried without success: if (@available(macCatalyst 18.0, *)) { self.tabBarController.tabBarHidden = false; } else { // Fallback on earlier versions } I wonder if this console log message has anything to do with the problem: CLIENT OF UIKIT REQUIRES UPDATE: This process does not adopt UIScene lifecycle. This will become an assert in a future version.
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2
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289
Activity
Jun ’25
chartXAxis AxisMark consisting of Month:Year
I have a Chart displaying Counts per Date over 2-3 years. I'd like to have the XAxis mark consist of MM-yy or even MM/nyy. Is this possible? OK, just saw AxisValueLabel(format: .dateTime.month().year()) which gives e.g. Mar 2024. This is good. Better might be Mar 24 (maybe a Y3K problem ;-) or even better Mar. OR Mar 24. 2024 Or best increment the year when it changes. Are any of these alternate formats possible? Thanks, David PS, my current .chartXAxis code .chartXAxis { AxisMarks(values: .stride(by: .month, count: 3)) { value in if value.as(Date.self) != nil { AxisValueLabel(format: .dateTime.month().year()) AxisGridLine() AxisTick() } } }
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207
Activity
Jun ’25
How can I make a new item from within a navigationlink?
Sorry if this is too basic, but I really can't figure out how to make this work. I am trying to make a journal app and I want to have a button that creates a new journalentry and then loads it. This code snippet (I removed irrelevant bits) shows how I'm trying to go about it. Basically, the newEntryButtons should launch a JournalPromptRoute for one of the different options: that's the method argument. But putting .createNewEntry() inside the argument means that new entries are being constantly created. I want the system to create a new entry once on the button press and then go to it from the navigationDestination area. Can anyone please explain to me how this is supposed to work? I believe the code snippet is detailed enough to get the point across but please let me know if you need more info. case library case blank(entry: Entry) case mystery case summary(entry: Entry) case entry(entry: Entry) } struct JournalHome: View { @ObservedObject var viewModel: JournalViewModel var mainContent: some View { ScrollView { newEntryButtons LazyVStack { ForEach(filteredEntries) { entry in NavigationLink( value: JournalPromptRoute.entry(entry: entry) ) { JournalCard(entry) } } } } } var body: some View { NavigationStack(path: $path) { mainContent .navigationDestination(for: JournalPromptRoute.self) { route in switch route { case .blank(let entry): JournalEntryView( entry: entry, index: 0, viewModel: viewModel ) } } } } var newEntryButtons: some View { ScrollView(.horizontal) { HStack(spacing: 15) { EntryButton( description: "Add blank entry", method: JournalPromptRoute.blank(entry: viewModel.createNewEntry()), viewModel: viewModel, path: $path ) EntryButton( description: "Select a Journey", method: JournalPromptRoute.library, viewModel: viewModel, path: $path ) EntryButton( description: "Let the Journey find you", method: JournalPromptRoute.mystery, viewModel: viewModel, path: $path ) } } } }
Topic: UI Frameworks SubTopic: SwiftUI
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104
Activity
Jun ’25
Understanding how to make focusedImage work on CPMapButton
When my CPMapButton is selected/focused, I would like to be able to provide a focusedImage to correctly show the button when the blue focus is shown. Currently I have: What do I need to do to create an image that works more like the panning interface buttons?
Topic: UI Frameworks SubTopic: UIKit Tags:
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264
Activity
Jun ’25
Status Bar Driving Orientation
With CarPlay, is it possible to programmatically know which side of the screen the status bar is placed on?
Topic: UI Frameworks SubTopic: UIKit Tags:
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2
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271
Activity
Jun ’25
popover no longer anchoring
My old UIKit popovers are no longer anchoring to their sourceView and sourceRect. Started happening while testing on IPadOS 18.5 after updating to Xcode 16.4. Has anyone else had to fix this problem? Popovers now slide up from the bottom to the center of the screen.
Topic: UI Frameworks SubTopic: UIKit
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1
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79
Activity
Jun ’25
SwiftUI internal crash when interacting with long list quickly
Hello! We encountered a very intermittent crash with our application starting with devices running iOS 18.4. We have a screen that can display a long list of products in 2 states (expanded or collapsed) based off of a boolean if the user has interacted with that product yet. With this list, we very intermittently encounter a crash when we scroll like crazy up and down the list search the list quickly (search is performed each character change and list is filtered) Our project has iOS 17.0 as a minimum deployment target, and is Swift 6 enabled. Again, this started happening only with iOS 18.4, and is still visible (handful of occurrences each week). The crash report seems to be very internal to SwiftUI/Obj-c runtime. 5895AC17-6886-4070-BC80-8912E8394BDB.crash Any insights would be greatly appreciated!
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204
Activity
Jun ’25
PKPass Framework
I am trying to work with the data inside the barcode string in shared PKPass. The documentation shows that is should look for @property (nonatomic, readonly, nullable) PKBarcode *primaryBarcode; I have tried to use it like this guard let code = pass.primaryBarcode?.message else { return } I get a constant message that PKPass has no member primaryBarcode The PKPass.h file in my IOS SDK does not seem to include the @property primaryBarcode or @property barcode. I am running Xcode 16.4 (16F6) and my app target is 17.6 + Is there a restriction on this property? I cannot find an SDK later than mine - the App Store does not offer one. I am unsure of this is a public or private issue - does anyone know? Thanks for reading this. Max
Topic: UI Frameworks SubTopic: SwiftUI
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102
Activity
Jun ’25
Highlight the model not with the eyes, but by clicking a button
Hello, we have a requirement where clicking a button will highlight the model, similar to the effect seen by the eyes. However, the eyes do not see it and it is achieved by clicking a button. What should we do? Thank you for your reply
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146
Activity
Jun ’25
App displays wrong localized image
I have an image in the xcassets file which is localized for different languages. When setting App language to Traditional Chinese, it always displays the Simplified Chinese image. This happens on latest iOS 18.5 system, but not on a lower system version. The feedback assistant ID is FB17663546
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0
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1
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114
Activity
Jun ’25