Hi, I'm relatively new to iOS development and kindly ask for some feedback on a strategy to achieve this desired behavior in my app.
My Question:
What would be the best strategy for sound effect playback when an app is in the background with precise timing? Is this even possible?
Context:
I created a basic countdown timer app (targeting iOS 17 with Swift/SwiftUI.). Countdown sessions can last up to 30-60 mins. When the timer is started it progresses through a series of sub-intervals and plays a short sound for each one. I used AVAudioPlayer and everything works fine when the app is in the foreground. I'm considering switching to AVAudioEngine b/c precise timing is very important and the AIs tell me this would have better precision.
I'm already setting "App plays audio or streams audio/video using AirPlay" in my Plist, and have configured:
AVAudioSession.sharedInstance().setCategory(.playback, mode: .default, options: .mixWithOthers)
Curiously, when testing on my iPhone 13 mini, sounds sometimes still play when the app is in the background, but not always.
What I've considered:
Background Tasks: Would they make any sense for this use-case? Seems like not if the allowed time is short & limited by the system.
Pre-scheduling all Sounds: Not sure this would even work and seems like a lot of memory would be needed (could be hundreds of intervals).
ActivityKit Alerts: works but with a ~50ms delay which is too long for my purposes.
Pre-Render all SFX to 1 large audio file: Seems like a lot of work and processing time and probably not worth it. I hope there's a better solution.
I'd really appreciate any feedback.
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I have an xcode project which has both cpp and swift code. In one of my usecase I am passing primitive type variables from swift to cpp by reference( primitives types list here as per the new cpp-swift interop documentation)
swift code:
// primitive check code:Bool
var x : Bool = true
// When we are passing a variable as a Reference, we need to use explicitly use'&'
student.PassBoolAsReferenceType (&x) // interop call to cpp code
print (x)
Cpp code:
void
Student::PassBoolAsReferenceType(bool &pValue) noexcept
{
std::cout << pValue << std::endl;
pValue = false;
}
The above code fails during compilation with no clear error message "Command SwiftCompile failed with a nonzero exit code"
However, all the other primitive types that I tested worked for the above code like Int, Float, Double etc. Only the Bool interop fails. Can someone explain why is it not possible for bool? I m using the new interop introduced in swift 5.9.
https://developer.apple.com/forums/thread/768776
Swift concurrency is an important part of my day-to-day job. I created the following document for an internal presentation, and I figured that it might be helpful for others.
If you have questions or comments, put them in a new thread here on DevForums. Use the App & System Services > Processes & Concurrency topic area and tag it with both Swift and Concurrency.
Share and Enjoy
—
Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"
Swift Concurrency Proposal Index
This post summarises the Swift Evolution proposals that went into the Swift concurrency design. It covers the proposal that are implemented in Swift 6.2, plus a few additional ones that aren’t currently available.
The focus is here is the Swift Evolution proposals. For general information about Swift concurrency, see the documentation referenced by Concurrency Resources.
Swift 6.0
The following Swift Evolution proposals form the basis of the Swift 6.0 concurrency design.
SE-0176 Enforce Exclusive Access to Memory
link: SE-0176
notes: This defines the “Law of Exclusivity”, a critical foundation for both serial and concurrent code.
SE-0282 Clarify the Swift memory consistency model ⚛︎
link: SE-0282
notes: This defines Swift’s memory model, that is, the rules about what is and isn’t allowed when it comes to concurrent memory access.
SE-0296 Async/await
link: SE-0296
introduces: async functions, async, await
SE-0297 Concurrency Interoperability with Objective-C
link: SE-0297
notes: Specifies how Swift imports an Objective-C method with a completion handler as an async method. Explicitly allows @objc actors.
SE-0298 Async/Await: Sequences
link: SE-0298
introduces: AsyncSequence, for await syntax
notes: This just defines the AsyncSequence protocol. For one concrete implementation of that protocol, see SE-0314.
SE-0300 Continuations for interfacing async tasks with synchronous code
link: SE-0300
introduces: CheckedContinuation, UnsafeContinuation
notes: Use these to create an async function that wraps a legacy request-reply concurrency construct.
SE-0302 Sendable and @Sendable closures
link: SE-0302
introduces: Sendable, @Sendable closures, marker protocols
SE-0304 Structured concurrency
link: SE-0304
introduces: unstructured and structured concurrency, Task, cancellation, CancellationError, withTaskCancellationHandler(…), sleep(…), withTaskGroup(…), withThrowingTaskGroup(…)
notes: For the async let syntax, see SE-0317. For more ways to sleep, see SE-0329 and SE-0374. For discarding task groups, see SE-0381.
SE-0306 Actors
link: SE-0306
introduces: actor syntax
notes: For actor-isolated parameters and the nonisolated keyword, see SE-0313. For global actors, see SE-0316. For custom executors and the Actor protocol, see SE-0392.
SE-0311 Task Local Values
link: SE-0311
introduces: TaskLocal
SE-0313 Improved control over actor isolation
link: SE-0313
introduces: isolated parameters, nonisolated
SE-0314 AsyncStream and AsyncThrowingStream
link: SE-0314
introduces: AsyncStream, AsyncThrowingStream, onTermination
notes: These are super helpful when you need to publish a legacy notification construct as an async stream. For a simpler API to create a stream, see SE-0388.
SE-0316 Global actors
link: SE-0316
introduces: GlobalActor, MainActor
notes: This includes the @MainActor syntax for closures.
SE-0317 async let bindings
link: SE-0317
introduces: async let syntax
SE-0323 Asynchronous Main Semantics
link: SE-0323
SE-0327 On Actors and Initialization
link: SE-0327
notes: For a proposal to allow access to non-sendable isolated state in a deinitialiser, see SE-0371.
SE-0329 Clock, Instant, and Duration
link: SE-0329
introduces: Clock, InstantProtocol, DurationProtocol, Duration, ContinuousClock, SuspendingClock
notes: For another way to sleep, see SE-0374.
SE-0331 Remove Sendable conformance from unsafe pointer types
link: SE-0331
SE-0337 Incremental migration to concurrency checking
link: SE-0337
introduces: @preconcurrency, explicit unavailability of Sendable
notes: This introduces @preconcurrency on declarations, on imports, and on Sendable protocols. For @preconcurrency conformances, see SE-0423.
SE-0338 Clarify the Execution of Non-Actor-Isolated Async Functions
link: SE-0338
note: This change has caught a bunch of folks by surprise and there’s a discussion underway as to whether to adjust it.
SE-0340 Unavailable From Async Attribute
link: SE-0340
introduces: noasync availability kind
SE-0343 Concurrency in Top-level Code
link: SE-0343
notes: For how strict concurrency applies to global variables, see SE-0412.
SE-0374 Add sleep(for:) to Clock
link: SE-0374
notes: This builds on SE-0329.
SE-0381 DiscardingTaskGroups
link: SE-0381
introduces: DiscardingTaskGroup, ThrowingDiscardingTaskGroup
notes: Use this for task groups that can run indefinitely, for example, a network server.
SE-0388 Convenience Async[Throwing]Stream.makeStream methods
link: SE-0388
notes: This builds on SE-0314.
SE-0392 Custom Actor Executors
link: SE-0392
introduces: Actor protocol, Executor, SerialExecutor, ExecutorJob, assumeIsolated(…)
notes: For task executors, a closely related concept, see SE-0417. For custom isolation checking, see SE-0424.
SE-0395 Observation
link: SE-0395
introduces: Observation module, Observable
notes: While this isn’t directly related to concurrency, it’s relationship to Combine, which is an important exising concurrency construct, means I’ve included it in this list.
SE-0401 Remove Actor Isolation Inference caused by Property Wrappers
link: SE-0401, commentary
availability: upcoming feature flag: DisableOutwardActorInference
SE-0410 Low-Level Atomic Operations ⚛︎
link: SE-0410
introduces: Synchronization module, Atomic, AtomicLazyReference, WordPair
SE-0411 Isolated default value expressions
link: SE-0411, commentary
SE-0412 Strict concurrency for global variables
link: SE-0412
introduces: nonisolated(unsafe)
notes: While this is a proposal about globals, the introduction of nonisolated(unsafe) applies to “any form of storage”.
SE-0414 Region based Isolation
link: SE-0414, commentary
notes: To send parameters and results across isolation regions, see SE-0430.
SE-0417 Task Executor Preference
link: SE-0417, commentary
introduces: withTaskExecutorPreference(…), TaskExecutor, globalConcurrentExecutor
notes: This is closely related to the custom actor executors defined in SE-0392.
SE-0418 Inferring Sendable for methods and key path literals
link: SE-0418, commentary
availability: upcoming feature flag: InferSendableFromCaptures
notes: The methods part of this is for “partial and unapplied methods”.
SE-0420 Inheritance of actor isolation
link: SE-0420, commentary
introduces: #isolation, optional isolated parameters
notes: This is what makes it possible to iterate over an async stream in an isolated async function.
SE-0421 Generalize effect polymorphism for AsyncSequence and AsyncIteratorProtocol
link: SE-0421, commentary
notes: Previously AsyncSequence used an experimental mechanism to support throwing and non-throwing sequences. This moves it off that. Instead, it uses an extra Failure generic parameter and typed throws to achieve the same result. This allows it to finally support a primary associated type. Yay!
SE-0423 Dynamic actor isolation enforcement from non-strict-concurrency contexts
link: SE-0423, commentary
introduces: @preconcurrency conformance
notes: This adds a number of dynamic actor isolation checks (think assumeIsolated(…)) to close strict concurrency holes that arise when you interact with legacy code.
SE-0424 Custom isolation checking for SerialExecutor
link: SE-0424, commentary
introduces: checkIsolation()
notes: This extends the custom actor executors introduced in SE-0392 to support isolation checking.
SE-0430 sending parameter and result values
link: SE-0430, commentary
introduces: sending
notes: Adds the ability to send parameters and results between the isolation regions introduced by SE-0414.
SE-0431 @isolated(any) Function Types
link: SE-0431, commentary, commentary
introduces: @isolated(any) attribute on function types, isolation property of functions values
notes: This is laying the groundwork for SE-NNNN Closure isolation control. That, in turn, aims to bring the currently experimental @_inheritActorContext attribute into the language officially.
SE-0433 Synchronous Mutual Exclusion Lock 🔒
link: SE-0433
introduces: Mutex
SE-0434 Usability of global-actor-isolated types
link: SE-0434, commentary
availability: upcoming feature flag: GlobalActorIsolatedTypesUsability
notes: This loosen strict concurrency checking in a number of subtle ways.
Swift 6.1
Swift 6.1 has the following additions.
Vision: Improving the approachability of data-race safety
link: vision
SE-0442 Allow TaskGroup’s ChildTaskResult Type To Be Inferred
link: SE-0442, commentary
notes: This represents a small quality of life improvement for withTaskGroup(…) and withThrowingTaskGroup(…).
SE-0449 Allow nonisolated to prevent global actor inference
link: SE-0449, commentary
notes: This is a straightforward extension to the number of places you can apply nonisolated.
Swift 6.2
Xcode 26 beta has two new build settings:
Approachable Concurrency enables the following feature flags: DisableOutwardActorInference, GlobalActorIsolatedTypesUsability, InferIsolatedConformances, InferSendableFromCaptures, and NonisolatedNonsendingByDefault.
Default Actor Isolation controls SE-0466
Swift 6.2, still in beta, has the following additions.
SE-0371 Isolated synchronous deinit
link: SE-0371, commentary
introduces: isolated deinit
notes: Allows a deinitialiser to access non-sendable isolated state, lifting a restriction imposed by SE-0327.
SE-0457 Expose attosecond representation of Duration
link: SE-0457
introduces: attoseconds, init(attoseconds:)
SE-0461 Run nonisolated async functions on the caller’s actor by default
link: SE-0461
availability: upcoming feature flag: NonisolatedNonsendingByDefault
introduces: nonisolated(nonsending), @concurrent
notes: This represents a significant change to how Swift handles actor isolation by default, and introduces syntax to override that default.
SE-0462 Task Priority Escalation APIs
link: SE-0462
introduces: withTaskPriorityEscalationHandler(…)
notes: Code that uses structured concurrency benefits from priority boosts automatically. This proposal exposes APIs so that code using unstructured concurrency can do the same.
SE-0463 Import Objective-C completion handler parameters as @Sendable
link: SE-0463
notes: This is a welcome resolution to a source of much confusion.
SE-0466 Control default actor isolation inference
link: SE-0466, commentary
availability: not officially approved, but a de facto part of Swift 6.2
introduces: -default-isolation compiler flag
notes: This is a major component of the above-mentioned vision document.
SE-0468 Hashable conformance for Async(Throwing)Stream.Continuation
link: SE-0468
notes: This is an obvious benefit when you’re juggling a bunch of different async streams.
SE-0469 Task Naming
link: SE-0469
introduces: name, init(name:…)
SE-0470 Global-actor isolated conformances
link: SE-0470
availability: upcoming feature flag: InferIsolatedConformances
introduces: @SomeActor protocol conformance
notes: This is particularly useful when you want to conform an @MainActor type to Equatable, Hashable, and so on.
SE-0471 Improved Custom SerialExecutor isolation checking for Concurrency Runtime
link: SE-0471
notes: This is a welcome extension to SE-0424.
SE-0472 Starting tasks synchronously from caller context
link: SE-0472
introduces: immediate[Detached](…), addImmediateTask[UnlessCancelled](…),
notes: This introduces the concept of an immediate task, one that initially uses the calling execution context. This is one of those things where, when you need it, you really need it. But it’s hard to summary when you might need it, so you’ll just have to read the proposal (-:
In Progress
The proposals in this section didn’t make Swift 6.2.
SE-0406 Backpressure support for AsyncStream
link: SE-0406
availability: returned for revision
notes: Currently AsyncStream has very limited buffering options. This was a proposal to improve that. This feature is still very much needed, but the outlook for this proposal is hazy. My best guess is that something like this will land first in the Swift Async Algorithms package. See this thread.
SE-NNNN Closure isolation control
link: SE-NNNN
introduces: @inheritsIsolation
availability: not yet approved
notes: This aims to bring the currently experimental @_inheritActorContext attribute into the language officially. It’s not clear how this will play out given the changes in SE-0461.
Revision History
2025-09-02 Updated for the upcoming release Swift 6.2.
2025-04-07 Updated for the release of Swift 6.1, including a number of things that are still in progress.
2024-11-09 First post.
I'm primarily an AppleScript writer and only a novice programmer, using ChatGPT to help me with the legwork. It has helped me to write a functioning app that builds a menu structure based on the scripts I have in the Scripts directory used in the script menu and then runs the applescripts. When I distribute the app to my desktop and run it, the scripts that access other apps, like InDesign will cause it to launch, but not actually do anything. I included the ids for each app in the entitlements dictionary and have given the app full disk access in system settings, but it's not functioning as I'd expect.
I know there are apps like Alfred that allow you to run scripts from a keystroke, but I'm building this for others I work with so they can also access info about each script, what it does, and how to use it from the menu, as well as key commands to run them.
Not sure what else to say, but if this sounds like a simple fix to anyone, please let me know.
iOS18.2 / iPhone16 pro / xcode16.2
'traitCollectionDidChange'
This function has been deprecated in iOS17.
However, when I debugged it, I confirmed that it is not called on iOS17, but it is called on iOS18.2.
What is the reason?
Issue:
During app execution, the intended method is not being called; instead, the method preceding (written above the intended method) is being executed.
For Example:
//In my case the ViewController class is at 3rd level of inheritance.
class ViewController: UIViewController {
func methodA() {
print("methodA")
}
func methodB() {
print("methodB")
}
}
let vc = ViewController()
vc.methodB()
Output: //"methodA"
Expected: //"methodB"
Observations:
Recent code changes have revealed that enabling the below Swift-6 flag leads to this linking issue. When this flag is commented out, the problem disappears.
.enableUpcomingFeature("InternalImportsByDefault")
Additionally, moving the intended method into an extension of the same class resolves the issue when the flag is enabled.
Conclusion:
To resolve the issue:
Comment out the Swift-6 flag.
Alternatively, move the method into an extension of the same class, which addresses the issue for this specific case.
I had similar issue in other class where it crashes with message "method not found", but actually the method is there. When moving the method into an extension of same class resolve this issue.
Any help is much appreciated.
Thanking you..
iOS18.2 / iPhone 16pro / Xcode 16.2
'traitCollectionDidChange'
This function has been deprecated since ios17.
However, in ios18, when I changed the app to the background state or changed it to the foreground state again, it was confirmed that the function worked.
It hasn't been confirmed in ios17, but why is it only confirmed in ios18?
I can't find a viable path to call StoreKit from C++ right now and would love some ideas.
I'm implementing the code exactly as shown at 4:09 in
https://developer.apple.com/videos/play/wwdc2023/10172/
However when I add any StoreKit functionality in I immediately get
"Actor isolated structure cannot be exposed in C++"
This makes me think I can't create a StoreKit view and call it from C++? Am I missing a better way? I don't think I can have another structure that holds the storeChooser in it because it will have the same problem (I assume, although I will check). Part of the issue seems to be that my app is C++ so there is no main function called in the swift for me to open this view with either, I was going to use the present function Zoe described (as below).
I've tried a lot of alternative approaches but it seems to be blocking async functions from showing in C++ as well. So I'm not sure how to access the basic product(for:) and purchase(product) functions.
import Foundation
import StoreKit
import SwiftUI
public struct storeChooser: View {
public var productIDs: [String]
public var fetchError: String
//@State //Note this is from the UI
@State public var products: [Product] = []
// @State private var isPresented = true
// weak private var host: UIViewController? = nil
public init() {
productIDs = ["20_super_crystals_v1"]
products = []
self.fetchError = "untried"
}
public var body: some View {
VStack(spacing: 20) {
Text( "Products")
ForEach(self.products) { product in
Button {
//dont do anything yet
} label: {
Text("\(product.displayPrice) - \(product.displayName)")
}
}
}.task {
do {
try await self.loadProducts()
} catch {
print(error)
}
}
}
public func queryProducts() {
Task {
do {
try await self.loadProducts()
} catch {
print(error)
}
}
}
public func getProduct1Name() -> String {
if self.products.count > 0 {
return self.products[0].displayName
} else {
return "empty"
}
}
private func loadProducts() async throws {
self.products = try await Product.products(for: self.productIDs)
}
/* public mutating func present(_ viewController: UIViewController) {
isPresented = true;
let host = UIHostingController(rootView: self)
host.rootView.host = host
viewController.present(host, animated: true)
} */
}
Given the below code with Swift 6 language mode, Xcode 16.2
If running with iOS 18+: the app crashes due to _dispatch_assert_queue_fail
If running with iOS 17 and below: there is a warning: warning: data race detected: @MainActor function at Swift6Playground/PublishedValuesView.swift:12 was not called on the main thread
Could anyone please help explain what's wrong here?
import SwiftUI
import Combine
@MainActor
class PublishedValuesViewModel: ObservableObject {
@Published var count = 0
@Published var content: String = "NA"
private var cancellables: Set<AnyCancellable> = []
func start() async {
let publisher = $count
.map { String(describing: $0) }
.removeDuplicates()
for await value in publisher.values {
content = value
}
}
}
struct PublishedValuesView: View {
@ObservedObject var viewModel: PublishedValuesViewModel
var body: some View {
Text("Published Values: \(viewModel.content)")
.task {
await viewModel.start()
}
}
}
Crashed: com.apple.root.user-initiated-qos.cooperative
0 libswift_Concurrency.dylib 0x67f40 swift_task_create_commonImpl(unsigned long, swift::TaskOptionRecord*, swift::TargetMetadataswift::InProcess const*, void (swift::AsyncContext* swift_async_context) swiftasynccall*, void*, unsigned long) + 528
1 libswift_Concurrency.dylib 0x64d78 swift_asyncLet_begin + 40
2 AAAA 0x47aef28 (1) suspend resume partial function for ActivityContextModule.fetchRecord(startDate:endDate:) + 50786796
3 libswift_Concurrency.dylib 0x60f5c swift::runJobInEstablishedExecutorContext(swift::Job*) + 252
4 libswift_Concurrency.dylib 0x62514 swift_job_runImpl(swift::Job*, swift::SerialExecutorRef) + 144
5 libdispatch.dylib 0x15ec0 _dispatch_root_queue_drain + 392
6 libdispatch.dylib 0x166c4 _dispatch_worker_thread2 + 156
7 libsystem_pthread.dylib 0x3644 _pthread_wqthread + 228
8 libsystem_pthread.dylib 0x1474 start_wqthread + 8
Hi There,
I have a iOS App which has been published and purely managing data by SwiftData. I use following simple codes everywhere in Views:
...
@Query var items: [Item]
....
if let firstItem = items.first( where: {...}) {
...
Then I encountered crash at Query that _items.wrapperdValue has some errors.
Then I tried to split first(where...) into ordinary way:
let filteredItems = items.filter(...)
if let firstItem = filteredItems.first {
...
It runs OK.
Is it a bug in SwiftData in 18.2 or I missed some steps to facilitate SwiftData macros?
I have been recently getting the following error seemingly randomly, when an event handler of a SwiftUI view accesses a relationship of a SwiftData model the view holds a reference to. I haven't yet found a reliable way of reproducing it:
SwiftData/BackingData.swift:866: Fatal error: This model instance was invalidated
because its backing data could no longer be found the store.
PersistentIdentifier(id: SwiftData.PersistentIdentifier.ID(url: COREDATA_ID_URL),
implementation: SwiftData.PersistentIdentifierImplementation)
What could cause this error? Could you suggest me a workaround?
Does SwiftUI now support the ability for a chart to have two different Y Axes? ChaptGPT seems to think it does, but I keep getting compiler errors in XCode.
I'm encountering an issue where certain images are not displaying on some iOS devices, while the same code works perfectly on others. There’s no error or crash — just some images fail to load or display. I've confirmed the image URLs and formats are correct.
Has anyone faced a similar issue or could suggest what might be causing this inconsistent behavior?
Thanks in advance!
Topic:
Programming Languages
SubTopic:
Swift
I’m experiencing a crash at runtime when trying to extract audio from a video. This issue occurs on both iOS 18 and earlier versions. The crash is caused by the following error:
*** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: '*** -[AVAssetExportSession exportAsynchronouslyWithCompletionHandler:] Cannot call exportAsynchronouslyWithCompletionHandler: more than once.
(0x1851435ec 0x1826dd244 0x1970c09c0 0x214d8f358 0x214d95899 0x190a1c8b9 0x214d8efd9 0x30204cef5 0x302053ab9 0x190a5ae39)
libc++abi: terminating due to uncaught exception of type NSException
My previous code worked fine, but it's crashing with Swift 6.
Does anyone know a solution for this?
Previous code:
func extractAudioFromVideo(from videoURL: URL, exportHandler: ((AVAssetExportSession, CurrentValueSubject<Float, Never>?) -> Void)? = nil, completion: @escaping (Swift.Result<URL, Error>) -> Void) {
let asset = AVAsset(url: videoURL)
// Create an AVAssetExportSession to export the audio track
guard let exportSession = AVAssetExportSession(asset: asset, presetName: AVAssetExportPresetAppleM4A) else {
completion(.failure(NSError(domain: "com.example.app", code: -1, userInfo: [NSLocalizedDescriptionKey: "Failed to create AVAssetExportSession"])))
return
}
// Set the output file type and path
guard let filename = videoURL.lastPathComponent.components(separatedBy: ["."]).first else { return }
let outputURL = VideoUtils.getTempAudioExportUrl(filename)
VideoUtils.deleteFileIfExists(outputURL.path)
exportSession.outputFileType = .m4a
exportSession.outputURL = outputURL
let audioExportProgressPublisher = CurrentValueSubject<Float, Never>(0.0)
if let exportHandler = exportHandler {
exportHandler(exportSession, audioExportProgressPublisher)
}
// Periodically check the progress of the export session
let timer = Timer.scheduledTimer(withTimeInterval: 0.1, repeats: true) { _ in
audioExportProgressPublisher.send(exportSession.progress)
}
// Export the audio track asynchronously
exportSession.exportAsynchronously {
switch exportSession.status {
case .completed:
completion(.success(outputURL))
case .failed:
completion(.failure(exportSession.error ?? NSError(domain: "com.example.app", code: -1, userInfo: [NSLocalizedDescriptionKey: "Unknown error occurred while exporting audio"])))
case .cancelled:
completion(.failure(NSError(domain: "com.example.app", code: -1, userInfo: [NSLocalizedDescriptionKey: "Export session was cancelled"])))
default:
completion(.failure(NSError(domain: "com.example.app", code: -1, userInfo: [NSLocalizedDescriptionKey: "Unknown export session status"])))
}
// Invalidate the timer when the export session completes or is cancelled
timer.invalidate()
}
}
## New Code:
func extractAudioFromVideo(from videoURL: URL, exportHandler: ((AVAssetExportSession, CurrentValueSubject<Float, Never>?) -> Void)? = nil, completion: @escaping (Swift.Result<URL, Error>) -> Void)
{
let asset = AVAsset(url: videoURL)
// Create an AVAssetExportSession to export the audio track
guard let exportSession = AVAssetExportSession(asset: asset, presetName: AVAssetExportPresetAppleM4A) else {
completion(.failure(NSError(domain: "com.example.app", code: -1, userInfo: [NSLocalizedDescriptionKey: "Failed to create AVAssetExportSession"])))
return
}
// Set the output file type and path
guard let filename = videoURL.lastPathComponent.components(separatedBy: ["."]).first else { return }
let outputURL = VideoUtils.getTempAudioExportUrl(filename)
VideoUtils.deleteFileIfExists(outputURL.path)
exportSession.outputFileType = .m4a
exportSession.outputURL = outputURL
let audioExportProgressPublisher = CurrentValueSubject<Float, Never>(0.0)
if let exportHandler {
exportHandler(exportSession, audioExportProgressPublisher)
}
let task = Task {
if #available(iOS 18.0, *) {
// Handle export for iOS 18 and later
let states = exportSession.states(updateInterval: 0.1)
for await state in states {
switch state {
case .pending, .waiting:
break
case .exporting(progress: let progress):
print("Exporting: \(progress.fractionCompleted)")
if progress.isFinished {
completion(.success(outputURL))
} else if progress.isCancelled {
completion(.failure(NSError(domain: "com.example.app", code: -1, userInfo: [NSLocalizedDescriptionKey: "Export session was cancelled"])))
} else {
audioExportProgressPublisher.send(Float(progress.fractionCompleted))
}
}
}
try await exportSession.export(to: outputURL, as: .m4a) // Only call export once
} else {
// Handle export for iOS versions below 18
let publishTimer = Timer.publish(every: 0.1, on: .main, in: .common)
.autoconnect()
.sink { [weak exportSession] _ in
guard let exportSession = exportSession else { return }
audioExportProgressPublisher.send(exportSession.progress)
}
// Only call export once
await exportSession.export()
// Handle the export session's status
switch exportSession.status {
case .completed:
completion(.success(outputURL))
case .failed:
completion(.failure(exportSession.error ?? NSError(domain: "com.example.app", code: -1, userInfo: [NSLocalizedDescriptionKey: "Unknown error occurred while exporting audio"])))
case .cancelled:
completion(.failure(NSError(domain: "com.example.app", code: -1, userInfo: [NSLocalizedDescriptionKey: "Export session was cancelled"])))
default:
completion(.failure(NSError(domain: "com.example.app", code: -1, userInfo: [NSLocalizedDescriptionKey: "Unknown export session status"])))
}
// Invalidate the timer when the export session completes or is cancelled
publishTimer.cancel()
}
}
task.cancel()
}
Topic:
Programming Languages
SubTopic:
Swift
System provides AnyShape type erasure that animates correctly. But system doesn't provide AnyInsettableShape. Here is my implementation of AnyInsettableShape (and AnyAnimatableData that is needed to support animation).
Let me know if there is simpler solution.
struct AnyInsettableShape: InsettableShape {
private let _path: (CGRect) -> Path
private let _inset: (CGFloat) -> AnyInsettableShape
private let _getAnimatableData: () -> AnyAnimatableData
private let _setAnimatableData: (_ data: AnyAnimatableData) -> AnyInsettableShape
init<S>(_ shape: S) where S : InsettableShape {
_path = { shape.path(in: $0) }
_inset = { AnyInsettableShape(shape.inset(by: $0)) }
_getAnimatableData = { AnyAnimatableData(shape.animatableData) }
_setAnimatableData = { data in
guard let otherData = data.rawValue as? S.AnimatableData else { assertionFailure(); return AnyInsettableShape(shape) }
var shape = shape
shape.animatableData = otherData
return AnyInsettableShape(shape)
}
}
var animatableData: AnyAnimatableData {
get { _getAnimatableData() }
set { self = _setAnimatableData(newValue) }
}
func path(in rect: CGRect) -> Path {
_path(rect)
}
func inset(by amount: CGFloat) -> some InsettableShape {
_inset(amount)
}
}
struct AnyAnimatableData : VectorArithmetic {
init<T : VectorArithmetic>(_ value: T) {
self.init(optional: value)
}
private init<T : VectorArithmetic>(optional value: T?) {
rawValue = value
_scaleBy = { factor in
(value != nil) ? AnyAnimatableData(value!.scaled(by: factor)) : .zero
}
_add = { other in
AnyAnimatableData(value! + (other.rawValue as! T))
}
_subtract = { other in
AnyAnimatableData(value! - (other.rawValue as! T))
}
_equal = { other in
value! == (other.rawValue as! T)
}
_magnitudeSquared = {
(value != nil) ? value!.magnitudeSquared : .zero
}
_zero = {
AnyAnimatableData(T.zero)
}
}
fileprivate let rawValue: (any VectorArithmetic)?
private let _scaleBy: (_: Double) -> AnyAnimatableData
private let _add: (_ other: AnyAnimatableData) -> AnyAnimatableData
private let _subtract: (_ other: AnyAnimatableData) -> AnyAnimatableData
private let _equal: (_ other: AnyAnimatableData) -> Bool
private let _magnitudeSquared: () -> Double
private let _zero: () -> AnyAnimatableData
mutating func scale(by rhs: Double) {
self = _scaleBy(rhs)
}
var magnitudeSquared: Double {
_magnitudeSquared()
}
static let zero = AnyAnimatableData(optional: nil as Double?)
@inline(__always)
private var isZero: Bool { rawValue == nil }
static func + (lhs: AnyAnimatableData, rhs: AnyAnimatableData) -> AnyAnimatableData {
guard let (lhs, rhs) = fillZeroTypes(lhs, rhs) else { return .zero }
return lhs._add(rhs)
}
static func - (lhs: AnyAnimatableData, rhs: AnyAnimatableData) -> AnyAnimatableData {
guard let (lhs, rhs) = fillZeroTypes(lhs, rhs) else { return .zero }
return lhs._subtract(rhs)
}
static func == (lhs: AnyAnimatableData, rhs: AnyAnimatableData) -> Bool {
guard let (lhs, rhs) = fillZeroTypes(lhs, rhs) else { return true }
return lhs._equal(rhs)
}
@inline(__always)
private static func fillZeroTypes(_ lhs: AnyAnimatableData, _ rhs: AnyAnimatableData) -> (AnyAnimatableData, AnyAnimatableData)? {
switch (!lhs.isZero, !rhs.isZero) {
case (true, true): (lhs, rhs)
case (true, false): (lhs, lhs._zero())
case (false, true): (rhs._zero(), rhs)
case (false, false): nil
}
}
}
These helper methods allow to use modifier methods in standard for SwiftUI short way.
extension View {
@inline(__always)
func modify(_ block: (_ view: Self) -> some View) -> some View {
block(self)
}
@inline(__always)
func modify<V : View, T>(_ block: (_ view: Self, _ data: T) -> V, with data: T) -> V {
block(self, data)
}
}
_
DISCUSSION
Suppose you have modifier methods:
func addBorder(view: some View) -> some View {
view.padding().border(Color.red, width: borderWidth)
}
func highlight(view: some View, color: Color) -> some View {
view.border(Color.red, width: borderWidth).overlay { color.opacity(0.3) }
}
_
Ordinar Decision
Your code may be like this:
var body: some View {
let image = Image(systemName: "globe")
let borderedImage = addBorder(view: image)
let highlightedImage = highlight(view: borderedImage, color: .red)
let text = Text("Some Text")
let borderedText = addBorder(view: text)
let highlightedText = highlight(view: borderedText, color: .yellow)
VStack {
highlightedImage
highlightedText
}
}
This code doesn't look like standard SwiftUI code.
_
Better Decision
Described above helper methods modify(:) and modify(:,with:) allow to write code in typical for SwiftUI short way:
var body: some View {
VStack {
Image(systemName: "globe")
.modify(addBorder)
.modify(highlight, with: .red)
Text("Some Text")
.modify(addBorder)
.modify(highlight, with: .yellow)
}
}
func textField(
_ textField: UITextField,
shouldChangeCharactersIn range: NSRange,
replacementString string: String
) -> Bool {
if
let delegate = delegate,
let shouldChangeCharactersIn = delegate.textField {
return shouldChangeCharactersIn(textField, range, string)
}
return true
}
This is from an extension
extension TextInput: UITextFieldDelegate, ObservableTextFieldDelegateProtocol {
The delegate is already a UITextFieldDelegate, but when you click on the error, it returns 7 instances of:
"Found this candidate in module 'UIKit' (UIKit.UITextFieldDelegate.textField)"
This doesn't give an error in Xcode 16. Is this an Xcode 26 bug?
My framework has private Objective-C API that is only used within the framework. It should not be exposed in the public interface (so it shouldn't be imported in the umbrella header).
To expose this API to Swift that's within the framework only the documentation seems to indicate that this needs to be imported in the umbrella header?
Import Code Within a Framework Target
To use the Objective-C declarations in files in the same framework target as your Swift code, configure an umbrella header as follows:
1.Under Build Settings, in Packaging, make sure the Defines Module setting for the framework target is set to Yes.
2.In the umbrella header, import every Objective-C header you want to expose to Swift.
Swift sees every header you expose publicly in your umbrella header. The contents of the Objective-C files in that framework are automatically available from any Swift file within that framework target, with no import statements. Use classes and other declarations from your Objective-C code with the same Swift syntax you use for system classes.
I would imagine that there must be a way to do this?
Hi guys,
I've been struggling for a few days with this really weird behaviour.
We made an app for our e-commerce website and found out that a part of the product page is missing.
For any reason, the header and first blocks of the page and footer are displayed, but then a massive part of the content is missing. This content is not loaded through ajax; that's why I don't understand why it's not displayed.
You can see here 2 screenshots of what the page should look like and what the page looks like with WKWebView.
I've been inspecting this with Safari; there isn't any blocking error in the console, and html elements are just empty. There is the div with class row and nothing in it.
The same website is working perfectly with native Android Webview.
If anyone has any clue to find out what's going wrong
Topic:
Programming Languages
SubTopic:
Swift