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How to detect if an iPad is configured as a Shared iPad (Apple School Manager)?
I'm working on an iOS/iPadOS app and need to determine programmatically whether the device is a Shared iPad as configured through Apple School Manager (ASM). Shared iPads allow multiple users to sign in with Managed Apple IDs and are typically used in educational environments. I want to identify this configuration at runtime within my app. I’ve looked into UIDevice, NSProcessInfo, and MDM-related APIs but haven't found a reliable way to detect whether the current device is a Shared iPad. Is there an API or method to check if the current iPad is configured as a Shared iPad (via ASM)? Any guidance or code examples would be appreciated.
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Jun ’25
@Observable with generic typed throw breaks SwiftCompile
@Observable seems not to work well with generic typed throw. The following code using @Observable with non-generic typed throw builds good: @Observable class ThrowsLoadingViewModel<R, E: Error> { private(set) var isLoading = true private(set) var error: E? = nil private(set) var data: R? = nil private var task: () throws(Error) -> R init(task: @escaping () throws(E) -> R) { self.task = task } func load() { do throws(Error) { self.data = try task() } catch { // self.error = error } self.isLoading = false } } But if I change Line 7 and 14 to generic, it'll breaks the build with a "Command SwiftCompile failed with a nonzero exit code" message : @Observable class ThrowsLoadingViewModel<R, E: Error> { private(set) var isLoading = true private(set) var error: E? = nil private(set) var data: R? = nil private var task: () throws(E) -> R init(task: @escaping () throws(E) -> R) { self.task = task } func load() { do throws(E) { self.data = try task() } catch { // self.error = error } self.isLoading = false } } A the same time, if I remove @Observable, the generic typed throw works again: class ThrowsLoadingViewModel<R, E: Error> { private(set) var isLoading = true private(set) var error: E? = nil private(set) var data: R? = nil private var task: () throws(E) -> R init(task: @escaping () throws(E) -> R) { self.task = task } func load() { do throws(E) { self.data = try task() } catch { // self.error = error } self.isLoading = false } } Currently the possible solution seems to fall back to use ObservableObject...
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Jun ’25
Horrendous Swift overlay of vDSP Fourier Transform functions
I'm very unpleased to have found out the hard way, that vDSP.FFT&amp;lt;T&amp;gt; where T : vDSP_FourierTransformable and its associated vDSP_FourierTransformFunctions, only does real-complex conversion!!! This is horribly misleading - the only hint that it calls vDSP_fft_zrop() (split-complex real-complex out-of-place) under the hood, not vDSP_fft_zop()[1], is "A 1D single- and double-precision fast Fourier transform." - instead of "a single- and double-precision complex fast Fourier transform". Holy ******* ****. Just look at how people miss-call this routine. Poor him, realizing he had to log2n+1 lest only the first half of the array was transformed, not understanding why [2]. And poor me, having taken days investigating why a simple Swift overlay vDSP.FFT.transform may execute at 1.4x the speed of vDSP_fft_zopt(out-of-place with temporary buffer)! [3] [1]: or better, vDSP_fft_zopt with the temp buffer alloc/dealloc taken care of, for us [2]: for real-complex conversion, say real signal of length 16. log2n is 4 no problem, but then the real and imaginary vectors are both length 8. Also, vDSP_fft only works on integer powers of 2, so he had to choose next integer power of 2 (i.e. 1&amp;lt;&amp;lt;(log2n-1)) instead of plain length for his internal arrays. [3]: you guessed it. fft_zrop(log2n-1, ...) vs. fft_zop(log2n, ...). Half the problem size lol. Now we have vDSP.DiscreteFourierTransform, which wraps vDSP_DFT routines and "calls FFT routines when the size allows it", and works too for interleaved complexes. Just go all DFT, right? if let setup_f = try? vDSP.DiscreteFourierTransform(previous: nil, count: 8, direction: .forward, transformType: .complexComplex, ofType: DSPComplex.self) { // Done forward transformation // and scaled the results with 1/N // How about going reverse? if let setup_r = try? vDSP.DiscreteFourierTransform(previous: setup_f, count: 8, direction: .inverse, transformType: .complexComplex, ofType: DSPComplex.self) { // Error: cannot convert vDSP.DiscreteFourierTransform&amp;lt;DSPComplex&amp;gt; to vDSP.DiscreteFourierTransform&amp;lt;Float&amp;gt; // lolz } } This API appeared in macOS 12. 3 years later nobody have ever noticed. I'm at a loss for words.
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Jun ’25
How to listen for Locale change event in iOS using NSLocale.currentLocaleDidChangeNotification?
I have the following function private func SetupLocaleObserver () { NotificationCenter.default.addObserver ( forName: NSLocale.currentLocaleDidChangeNotification, object: nil, queue: .main ) {_ in print ("Locale changed to: \(Locale.current.identifier)"); } } I call this function inside the viewDidLoad () method of my view controller. The expectation was that whenever I change the system or app-specific language preference, the locale gets changed, and this change triggers my closure which should print "Locale changed to: " on the console. However, the app gets terminated with a SIGKILL whenever I change the language from the settings. So, it is observed that sometimes my closure runs, while most of the times it does not run - maybe the app dies even before the closure is executed. So, the question is, what is the use of this particular notification if the corresponding closure isn't guaranteed to be executed before the app dies? Or am I using it the wrong way?
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Jun ’25
AVCaptureVideoPreviewLayer layoutSublayers invoked on background thread
Opening this question after discussing the issue in the AVCapture lab, hopefully so we can track down this issue. We've been noticing some crashes in App Store Connect caused by layoutSublayers being called on a background thread. After debugging the issue a bit we found that all calls which modified the AVCaptureSession or preview layer were indeed done on the main thread. It would be useful to see what results in AVCaptureVideoPreviewLayer.updateFormatDescription being called. I've attached the crashlog below. Crash log.ips - https://developer.apple.com/forums/content/attachment/800b0dba-3477-4c5a-b56c-f4cc393b384f
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Jun ’25
Understanding an assertion failure in a crash log
Last night my iPhone game crashed while running in debug mode on my iPhone. I just plugged it into my Mac, and was able to find the ips file. The stack trace shows the function in my app where it crashed, and then a couple of frames in libswiftCore.dylib before an assertion failure. My question is - I've got absolutely no idea what the assertion failure actually was, all I have is... 0 libswiftCore.dylib 0x1921412a0 closure #1 in closure #1 in closure #1 in _assertionFailure(_:_:file:line:flags:) + 228 1 libswiftCore.dylib 0x192141178 closure #1 in closure #1 in _assertionFailure(_:_:file:line:flags:) + 327 2 libswiftCore.dylib 0x192140b4c _assertionFailure(_:_:file:line:flags:) + 183 3 MyGame.debug.dylib 0x104e52818 SentryBrain.takeTurn(actor:) + 1240 ... How do I figure out what the assertion failure was that triggered the crash? How do I figure out what line of code in takeTurn(...) triggered the failing assertion failure?
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Jun ’25
Question about `UITextField`'s `markedTextRange` when handling Korean input
I'm currently working on implementing a character limit for Korean text input using UITextField, but I've encountered two key issues. 1. How can I determine if Korean input is complete? I understand that markedTextRange represents provisional (composing) text during multistage text input systems (such as Korean, Japanese, Chinese). While testing with Korean input, I expected markedTextRange to reflect the composing state. However, it seems that markedTextRange remains nil throughout the composition process. 2. Problems limiting character count for Korean input I’ve tried two methods to enforce a character limit. Both lead to incorrect behavior due to how Korean characters are composed. Method 1 – Before replacement: func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -&gt; Bool { guard let text = textField.text else { return true } return text.count &lt;= 5 } This checks the text length before applying the replacementString. The issue is that when the user enters a character that is meant to combine with the previous one to form a composed character, the input should result in a single, combined character. However, because the character limit check is based on the state before the replacement is applied, the second character does not get composed as expected. Method 2 – After change: textField.addTarget(self, action: #selector(editingChanged), for: .editingChanged) @objc private func editingChanged(_ sender: UITextField) { guard var text = sender.text else { return } if text.count &gt; limitCount { text.removeLast() sender.text = text } } This removes the last character if the count exceeds the limit after the change. But when a user keeps typing past the limit, the last character is overwritten by new input. I suspect this happens because the .editingChanged event occurs before the multistage input is finalized, and the final composed character is applied after that event. My understanding of the input flow: Standard input: shouldChangeCharactersIn is called replacementString is applied .editingChanged is triggered With multistage input (Korean, etc.): shouldChangeCharactersIn is called replacementString is applied .editingChanged is triggered Final composed character is inserted (after all the above) Conclusion Because both approaches lead to incorrect character count behavior with Korean input, I believe I need a new strategy. Is there an officially recommended way to handle multistage input properly with UITextField in this context? Any advice or clarification would be greatly appreciated. MacOS 15.5(24F74) Xcode 16.4 (16F6)
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Jun ’25
New to Apple Developer Forums — Guidance Appreciated
Hi everyone 👋, I’m new to the Apple Developer Forums and just getting started with building apps for iOS/macOS. I’ve explored the documentation but wanted to introduce myself and ask for some advice from experienced developers. Currently working on: An iOS app using SwiftUI Learning more about integrating Sign in with Apple Exploring best practices for App Store submission Here’s what I’d like to know: What is the recommended approach to saving minimal app state before termination? Are there SwiftUI lifecycle metho18336114753ds or SceneDelegate hooks I should be aware of? Is UserDefaults the best tool for small state preservation in this context? Would love to hear from anyone who’s implemented sim18336114753ilar behavior — even a high-level suggestion would help. Thanks! Harjeet Singh
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Jun ’25
Capturing self instead of using self. in switch case in DispatchQueue causes compiler error
I have an @objC used for notification. kTag is an Int constant, fieldBeingEdited is an Int variable. The following code fails at compilation with error: Command CompileSwift failed with a nonzero exit code if I capture self (I edited code, to have minimal case) @objc func keyboardDone(_ sender : UIButton) { DispatchQueue.main.async { [self] () -> Void in switch fieldBeingEdited { case kTag : break default : break } } } If I explicitly use self, it compiles, even with self captured: @objc func keyboardDone(_ sender : UIButton) { DispatchQueue.main.async { [self] () -> Void in switch fieldBeingEdited { // <<-- no need for self here case self.kTag : break // <<-- self here default : break } } } This compiles as well: @objc func keyboardDone(_ sender : UIButton) { DispatchQueue.main.async { () -> Void in switch self.fieldBeingEdited { // <<-- no need for self here case self.kTag : break // <<-- self here default : break } } } Is it a compiler bug or am I missing something ?
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Jun ’25
❗️Xcode-beta: “missing required module ‘SwiftShims’” and C99 PCH conflict
Hi all, I’m running into a persistent build issue with my Swift project ORSOFINAL after migrating from Xcode stable to Xcode-beta.app 26 (June 2025 version). ⸻ 💥 Errors displayed: 1. C99 was enabled in PCH file but is currently disabled 2. module file .../ModuleCache.noindex/SwiftShims-AXUM98L131W4...pcm cannot be loaded due to a configuration mismatch with the current compilation 3. missing required module 'SwiftShims' ⸻ 🛠 What I’ve already tried: • xcode-select -s /Applications/Xcode-beta.app/Contents/Developer • Deleted ~/Library/Developer/Xcode/DerivedData, ModuleCache.noindex, Archives, and Products • Ran sudo xcodebuild -runFirstLaunch • Clean Build Folder in Xcode-beta • Verified Command Line Tools setting points to Xcode-beta ⸻ ❓Looking for guidance on: • Whether this is a known bug in Xcode-beta • If SwiftShims/PCM conflicts are expected between versions • Best practices to safely migrate from Xcode stable to beta for Swift-based projects Any advice is much appreciated. Thanks, Mathéo
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Jun ’25
Xcode-beta project ORSOFINAL: SwiftShims & C99 PCH errors after migration from Xcode stable
Hi all, I’m running into a persistent build issue with my Swift project ORSOFINAL after migrating from Xcode stable to Xcode-beta.app (June 2025 version). ⸻ 💥 Errors displayed: 1. C99 was enabled in PCH file but is currently disabled 2. module file .../ModuleCache.noindex/SwiftShims-AXUM98L131W4...pcm cannot be loaded due to a configuration mismatch with the current compilation 3. missing required module 'SwiftShims' ⸻ 🛠 What I’ve already tried: • xcode-select -s /Applications/Xcode-beta.app/Contents/Developer • Deleted ~/Library/Developer/Xcode/DerivedData, ModuleCache.noindex, Archives, and Products • Ran sudo xcodebuild -runFirstLaunch • Clean Build Folder in Xcode-beta • Verified Command Line Tools setting points to Xcode-beta ⸻ ❓Looking for guidance on: • Whether this is a known bug in Xcode-beta • If SwiftShims/PCM conflicts are expected between versions • Best practices to safely migrate from Xcode stable to beta for Swift-based projects Any advice is much appreciated. Thanks, Mathéo
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Jun ’25
iBeacon with CLMonitor Slow
The other day I was playing with iBeacon and found out that CLBeaconIdentityConstraint will be deprecated after iOS 18.5. So I've written code with BeaconIdentityCondition in reference to this Apple's sample project. import Foundation import CoreLocation let monitorName = "BeaconMonitor" @MainActor public class BeaconViewModel: ObservableObject { private let manager: CLLocationManager static let shared = BeaconViewModel() public var monitor: CLMonitor? @Published var UIRows: [String: [CLMonitor.Event]] = [:] init() { self.manager = CLLocationManager() self.manager.requestWhenInUseAuthorization() } func startMonitoringConditions() { Task { print("Set up monitor") monitor = await CLMonitor(monitorName) await monitor!.add(getBeaconIdentityCondition(), identifier: "TestBeacon") for identifier in await monitor!.identifiers { guard let lastEvent = await monitor!.record(for: identifier)?.lastEvent else { continue } UIRows[identifier] = [lastEvent] } for try await event in await monitor!.events { guard let lastEvent = await monitor!.record(for: event.identifier)?.lastEvent else { continue } if event.state == lastEvent.state { continue } UIRows[event.identifier] = [event] UIRows[event.identifier]?.append(lastEvent) } } } func updateRecords() async { UIRows = [:] for identifier in await monitor?.identifiers ?? [] { guard let lastEvent = await monitor!.record(for: identifier)?.lastEvent else { continue } UIRows[identifier] = [lastEvent] } } func getBeaconIdentityCondition() -> CLMonitor.BeaconIdentityCondition { CLMonitor.BeaconIdentityCondition(uuid: UUID(uuidString: "abc")!, major: 123, minor: 789) } } It works except that my sample app can take as long as 90 seconds to see event changes. You would get an instant update with an fashion (CLBeacon and CLBeaconIdentityConstraint). Is there anything that I can do to see changes faster? Thanks.
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Jun ’25
How to achieve a pure backdrop blur effect without predefined tint color in SwiftUI / UIKit?
Hi everyone, I’m currently trying to create a pure backdrop blur effect in my iOS app (SwiftUI / UIKit), similar to the backdrop-filter: blur(20px) effect in CSS. My goal is simple: • Apply a Gaussian blur (radius ~20px) to the background content • Overlay a semi-transparent black layer (opacity 0.3) • Avoid any predefined color tint from UIBlurEffect or .ultraThinMaterial, etc. However, every method I’ve tried so far (e.g., .ultraThinMaterial, UIBlurEffect(style:)) always introduces a built-in tint, which makes the result look gray or washed out. Even when layering a black color with opacity 0.3 over .ultraThinMaterial, it doesn’t give the clean, transparent-black + blur look I want. What I’m looking for: • A clean 20px blur effect (like CIGaussianBlur) • No color shift/tint added by default • A layer of black at 30% opacity on top of the blur • Ideally works live (not a static snapshot blur) Has anyone achieved something like this in UIKit or SwiftUI? Would really appreciate any insights, workarounds, or libraries that can help. Thanks in advance! Ben
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Jun ’25