Discuss Swift.

Swift Documentation

Posts under Swift subtopic

Post

Replies

Boosts

Views

Activity

Basic c++ main xcodeproj call to swift struct
I can't find any simple c++ xcodeproj call to swift struct using modern c++ swift mix. there is the fibonacci example that is swift app call to c++. Base on fibonacci example I create new simple project and fail to build it with error when I try to include #include <SwiftMixTester/SwiftMixTester-Swift.h> What is wrong? Is it the right place to ask this? Any work project link? Xcode 26.
1
0
890
Oct ’25
Game Center fetchSavedGames sometimes returns empty list of games, although it works correctly on the next tries
I have implemented the Game Center for authentication and saving player's game data. Both authentication and saving player's data works correctly all the time, but there is a problem with fetching and loading the data. The game works like this: At the startup, I start the authentication After the player successfully logs in, I start loading the player's data by calling fetchSavedGames method If a game data exists for the player, I receive a list of SavedGame object containing the player's data The problem is that after I uninstall the game and install it again, sometimes the SavedGame list is empty(step 3). But if I don't uninstall the game and reopen the game, this process works fine. Here's the complete code of Game Center implementation: class GameCenterHandler { public func signIn() { GKLocalPlayer.local.authenticateHandler = { viewController, error in if let viewController = viewController { viewController.present(viewController, animated: false) return } if error != nil { // Player could not be authenticated. // Disable Game Center in the game. return } // Auth successfull self.load(filename: "TestFileName") } } public func save(filename: String, data: String) { if GKLocalPlayer.local.isAuthenticated { GKLocalPlayer.local.saveGameData(Data(data.utf8), withName: filename) { savedGame, error in if savedGame != nil { // Data saved successfully } if error != nil { // Error in saving game data! } } } else { // Error in saving game data! User is not authenticated" } } public func load(filename: String) { if GKLocalPlayer.local.isAuthenticated { GKLocalPlayer.local.fetchSavedGames { games, error in if let game = games?.first(where: {$0.name == filename}){ game.loadData { data, error in if data != nil { // Data loaded successfully } if error != nil { // Error in loading game data! } } } else { // Error in loading game data! Filename not found } } } else { // Error in loading game data! User is not authenticated } } } I have also added Game Center and iCloud capabilities in xcode. Also in the iCloud section, I selected the iCloud Documents and added a container. I found a simillar question here but it doesn't make things clearer.
1
0
848
5d
Parameter Errors - procedural vs. optional
So I’m writing a program, as a developer would - ‘with Xcode.’ Code produced an error. The key values were swapped. The parameters suggested were ‘optional parameters variables.’ “var name: TYPE? = (default)” var name0: TYPE ============================= name0 = “super cool” ‘Name is not yet declared at this point provided with x - incorrect argument replace ExampleStruct(name:”supercool”) should be x - incorrect argument replace ExampleStruct(name0:”supercool”) ============================= In swift, there is a procedural prioritization within the constructor calling process. Application calls constructor. Constructor provides constructor signature. Signature requires parameters & throws an error if the params are not in appropriate order. - “got it compiler; thank you, very much” Typically, when this occurs, defaults will be suggested. Often the variable type. Ie String, Bool. such as: StructName(param1:Int64, param2:Bool) (Recently, I have seen a decline in @Apple’s performance in many vectors.) As stated before, the key value pairs were out of sequence. The optionals were suggested instead of the required parameters. This leads me to believe that there is an order of operations in the calling procedure that is being mismanaged. I.e. regular expression, matching with optional. This confuses these with [forced, required] parameters, and the mismanagement of ‘key: value’ pairs. this is a superficial prognosis and would like to know if anyone has any insight as to why this may occur. Could it be a configuration setting? Is it possibly the network I connected to bumped into something. Etc.. I appreciate any and all feedback. Please take into consideration the Apple developer forum, guidelines before posting comments. #dev_div
1
0
129
4d
How to disable native Full Screen and implement custom "Zoom to Fill" with minimum window constraints in MacOs SwiftUI / Appkit
I am creating a macOs SwiftUI document based app, and I am struggling with the Window sizes and placements. Right now by default, a normal window has the minimize and full screen options which makes the whole window into full screen mode. However, I don't want to do this for my app. I want to only allow to fill the available width and height, i.e. exclude the status bar and doc when the user press the fill window mode, and also restrict to resize the window beyond a certain point ( which ideally to me is 1200 x 700 because I am developing on macbook air 13.3-inch in which it looks ideal, but resizing it below that makes the entire content inside messed up ). I want something like this below instead of the default full screen green When the user presses the button, it should position centered with perfect aspect ratio from my content ( or the one I want like 1200 x 700 ) and can be able to click again to fill the available width and height excluding the status bar and docs. Here is my entire @main code :- @main struct PhiaApp: App { @NSApplicationDelegateAdaptor(AppDelegate.self) var appDelegate var body: some Scene { DocumentGroup(newDocument: PhiaProjectDocument()) { file in ContentView( document: file.$document, rootURL: file.fileURL ) .configureEditorWindow(disableCapture: true) .background(AppColors.background) .preferredColorScheme(.dark) } .windowStyle(.hiddenTitleBar) .windowToolbarStyle(.unified) .defaultLaunchBehavior(.suppressed) Settings { SettingsView() } } } struct WindowAccessor: NSViewRepresentable { var callback: (NSWindow?) -> Void func makeNSView(context: Context) -> NSView { let view = NSView() DispatchQueue.main.async { [weak view] in callback(view?.window) } return view } func updateNSView(_ nsView: NSView, context: Context) { } } extension View { func configureEditorWindow(disableCapture: Bool = true) -> some View { self.background( WindowAccessor { window in guard let window else { return } if let screen = window.screen ?? NSScreen.main { let visible = screen.visibleFrame window.setFrame(visible, display: true) window.minSize = visible.size } window.isMovable = true window.isMovableByWindowBackground = false window.sharingType = disableCapture ? .captureBlocked : .captureAllowed } ) } } This is a basic setup I did for now, this automatically fills the available width and height on launch, but user can resize and can go beyond my desired min width and height which makes the entire content inside messy. As I said, I want a native way of doing this, respect the content aspect ratio, don't allow to enter full screen mode, only be able to fill the available width and height excluding the status bar and doc, also don't allow to resize below my desired width and height.
1
0
390
3d
Strange crash when using .values from @Published publisher
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() } } }
2
0
609
Dec ’24
Model instance invalidated, backing data could no longer be found in the store
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?
2
0
955
Dec ’24
SwiftData and 'NSKeyedUnarchiveFromData' should not be used to for un-archiving and will be removed in a future release
I get this red warning in Xcode every time my app is syncing to the iCloud. My model has only basic types and enum that conform to Codable so i'm not sure what is the problem. App is working well, synchronization works. But the warning doesn't look good. Maybe someone has idea how to debug it.
2
0
926
Dec ’24
Questions about calculate the square root using Accelerate
I am currently studying the Accelerate library by referring to Apple documentation. Here is the link to the referenced document: https://developer.apple.com/documentation/accelerate/veclib/vforce When I executed the sample code provided at the bottom of the document, I found a case where the results were different. let n = 10_000 let x = (0..&lt;n).map { _ in Float.random(in: 1 ... 10_000) } let y = x.map { return sqrt($0) } and let y = [Float](unsafeUninitializedCapacity: n) { buffer, initializedCount in vForce.sqrt(x, result: &amp;buffer) initializedCount = n } The code below is provided to observe the issue described above. import Accelerate Task { let n = 1//10_000 let x = (0..&lt;n).map { _ in Float(6737.015)//Float.random(in: 1 ... 10_000) } let y = x.map { return sqrt($0) } try? await Task.sleep(nanoseconds: 1_000_000_000) let z = [Float](unsafeUninitializedCapacity: n) { buffer, initializedCount in vForce.sqrt(x, result: &amp;buffer) initializedCount = n } } For a value of 6737.015 when calculating the square root: Using the sqrt(_:) function gives the result 82.07932, While using the vForce.sqrt(_:result:) function gives the result 82.07933. Using a calculator, the value comes out as 82.07932139, which shows that the result from vForce is incorrect. Could you explain the reason behind this difference?
2
0
549
Jan ’25
indices(where:) Swift Playgrounds Issue: "Cannot call value of non-function type Range<Int>"
Hey there- I'm having a quite interesting bug on Swift Playgrounds. I am trying to run my app with this following code snippet which does not compile on Swift Playgrounds, yet compiles on XCode (note: this is a Swift Playground app) if #available(iOS 18.0, *) { //simple function to get the indices of other items that have the same date as the "date" variable let indices = data!.indices(where: { item in let sameMonth = Calendar.current.component(.month, from: item.time) == Calendar.current.component(.month, from: date) let sameYear = Calendar.current.component(.year, from: item.time) == Calendar.current.component(.year, from: date) let sameDay = Calendar.current.component(.day, from: item.time) == Calendar.current.component(.year, from: date) return sameDay && sameMonth && sameYear }) However, the indices(where:) codeblock seems to stop the app from compiling (ONLY on Swift Playgrounds - it works perfectly fine on XCode). I am getting the following error: Cannot call value of non-function type 'Range<Array<Int>.Index>' (aka 'Range<Int>') Please let me know if you have any insight regarding this issue. -ColoredOwl
2
1
571
Jan ’25
Swift 6 concurrency. Apple Watch App target and -disable-dynamic-actor-isolation.
I've got a watch app, still with storyboard, WKInterfaceController and WatchConnectivity. After updating it for swift 6 concurrency I thought I'd keep it for a little while without swift 6 concurrency dynamic runtime check. So I added -disable-dynamic-actor-isolation in OTHER_SWIFT_FLAGS, but it doesn't seem to have an effect for the Apple Watch target. Without manually marking callbacks where needed with @Sendable in dynamic checks seem to be in place. swiftc invocation is as (includes -disable-dynamic-actor-isolation): swiftc -module-name GeoCameraWatchApp -Onone -enforce-exclusivity\=checked ... GeoCameraWatchApp.SwiftFileList -DDEBUG -enable-bridging-pch -disable-dynamic-actor-isolation -D DEBUG -enable-experimental-feature DebugDescriptionMacro -sdk /Applications/Xcode.app/Contents/Developer/Platforms/WatchOS.platform/Developer/SDKs/WatchOS11.2.sdk -target arm64_32-apple-watchos7.0 -g -module-cache-path /Users/stand/Library/Developer/Xcode/DerivedData/ModuleCache.noindex -Xfrontend -serialize-debugging-options -enable-testing -index-store-path /Users/stand/Library/Developer/Xcode/DerivedData/speedo-almhjmryctkitceaufvkvhkkfvdw/Index.noindex/DataStore -enable-experimental-feature OpaqueTypeErasure -Xcc -D_LIBCPP_HARDENING_MODE\=_LIBCPP_HARDENING_MODE_DEBUG -swift-version 6 ... -disable-dynamic-actor-isolation flag seems to be working for the iOS targets, I believe. The flag is described here Am I missing something? Should the flag work for both iOS and Apple Watch targets?
2
0
644
Jan ’25
NSDictionary.isEqual(to:) with Swift dictionary compiles on macOS but not on iOS
The following code works when compiling for macOS: print(NSMutableDictionary().isEqual(to: NSMutableDictionary())) but produces a compiler error when compiling for iOS: 'NSMutableDictionary' is not convertible to '[AnyHashable : Any]' NSDictionary.isEqual(to:) has the same signature on macOS and iOS. Why does this happen? Can I use NSDictionary.isEqual(_:) instead?
2
0
504
Feb ’25
cell.textLabel?.text breaking if a number value is in an array
Hi the below array and code to output a list item works fine: var quotes = [ [ "quote": "I live you the more ...", "order": "1" ], [ "quote": "There is nothing permanent ...", "order": "2" ], [ "quote": "You cannot shake hands ...", "order": "3" ], [ "quote": "Lord, make me an instrument...", "order": "4" ] ] cell.textLabel?.text = quotes[indexPath.row]["quote"] However if I change the "order" values to be numbers rather than text like below then for the above line I get an error message in Xcode "No exact matches in call to subscript". Please could someone tell me how to make it work with the numbers stored as numbers? (I'm wondering if creating an any array type and using the .text function has caused a conflict but I can't find how to resolve) [ "quote": "I live you the more ...", "order": 1 ], [ "quote": "There is nothing permanent ...", "order": 2 ], [ "quote": "You cannot shake hands ...", "order": 3 ], [ "quote": "Lord, make me an instrument...", "order": 4 ] ] Thank you for any pointers :-)
2
0
452
Feb ’25
Swift 6 crash calling requestAutomaticPassPresentationSuppression
I found a similar problem here https://developer.apple.com/forums/thread/764777 and I could solve my problem by wrapping the call to requestAutomaticPassPresentationSuppression in a call to DispatchQueue.global().async. But my question is if this is really how things should work. Even with strict concurrency warnings in Swift 6 I don't get any warnings. Just a runtime crash. How are we supposed to find these problems? Couldn't the compiler assist with a warning/error. Why does the compiler make the assumptions it does about the method that is declared like this: @available(iOS 9.0, *) open class func requestAutomaticPassPresentationSuppression(responseHandler: @escaping (PKAutomaticPassPresentationSuppressionResult) -> Void) -> PKSuppressionRequestToken Now that we have migrated to Swift 6 our code base contains a bunch of unknown places where it will crash as above.
2
0
489
Feb ’25
DebugDescription macro causing “String Interpolation” warnings
Using the DebugDescription macro to display an optional value produces a “String interpolation produces a debug description for an optional value” build warning. For example: @DebugDescription struct MyType: CustomDebugStringConvertible { let optionalValue: String? public var debugDescription: String { "Value: \(optionalValue)" } } The DebugDescription macro does not allow (it is an error) "Value: \(String(describing: optionalValue))" or "Value: \(optionalValue ?? "nil")" because “Only references to stored properties are allowed.” Is there a way to reconcile these? I have a build log full of these warnings, obscuring real issues.
2
0
501
Feb ’25
NSPredicate return wrong result
NSPredicate(format: "SELF MATCHES %@", "^[0-9A-Z]+$").evaluate(with: "126𝒥ℰℬℬ𝒢𝒦𝒮33") Returns true, and I don't know why. 𝒥ℰℬℬ𝒢𝒦𝒮 is not between 0-9 and A-Z, and why it returns true? How to avoid similar problem like this when using NSPredicate?
2
0
552
Feb ’25
How to create an array using a loop
Hello, Please can you tell me how to create an array of dictionaries? This code below should create 4 dictionaries in an array, but I'm getting these errors: For line "var output = [id: "testID", name: "testName"]": cannot find 'name' in scope Type '(any AnyObject).Type' cannot conform to 'Hashable' For line "return output": Type '(any AnyObject).Type' cannot conform to 'Hashable' var quotes: [(id: String, name: String)] { var output = [[(id: String, name: String)]] () for i in 1...4 { var output = [id: "testID", name: "testName"] } return output }
2
0
379
Mar ’25
iOS Share Extension Warning: Passing argument of non-sendable type outside of main actor-isolated context may introduce data races
Consider this simple miniature of my iOS Share Extension: import SwiftUI import Photos class ShareViewController: UIViewController { override func viewDidLoad() { super.viewDidLoad() if let itemProviders = (extensionContext?.inputItems.first as? NSExtensionItem)?.attachments { let hostingView = UIHostingController(rootView: ShareView(extensionContext: extensionContext, itemProviders: itemProviders)) hostingView.view.frame = view.frame view.addSubview(hostingView.view) } } } struct ShareView: View { var extensionContext: NSExtensionContext? var itemProviders: [NSItemProvider] var body: some View { VStack{} .task{ await extractItems() } } func extractItems() async { guard let itemProvider = itemProviders.first else { return } guard itemProvider.hasItemConformingToTypeIdentifier(UTType.url.identifier) else { return } do { guard let url = try await itemProvider.loadItem(forTypeIdentifier: UTType.url.identifier) as? URL else { return } try await downloadAndSaveMedia(reelURL: url.absoluteString) extensionContext?.completeRequest(returningItems: []) } catch {} } } On the line 34 guard let url = try await itemProvider.loadItem ... I get these warnings: Passing argument of non-sendable type '[AnyHashable : Any]?' outside of main actor-isolated context may introduce data races; this is an error in the Swift 6 language mode 1.1. Generic enum 'Optional' does not conform to the 'Sendable' protocol (Swift.Optional) Passing argument of non-sendable type 'NSItemProvider' outside of main actor-isolated context may introduce data races; this is an error in the Swift 6 language mode 2.2. Class 'NSItemProvider' does not conform to the 'Sendable' protocol (Foundation.NSItemProvider) How to fix them in Xcode 16? Please provide a solution which works, and not the one which might (meaning you run the same code in Xcode, add your solution and see no warnings). I tried Decorating everything with @MainActors Using @MainActor in the .task @preconcurrency import Decorating everything with @preconcurrency Playing around with nonisolated
2
0
555
Mar ’25
Use FormatStyle to print formatted values from a Vector structure
I'm trying to use FormatStyle from Foundation to format numbers when printing a vector structure. See code below. import Foundation struct Vector<T> { var values: [T] subscript(item: Int) -> T { get { values[item] } set { values[item] = newValue } } } extension Vector: CustomStringConvertible { var description: String { var desc = "( " desc += values.map { "\($0)" }.joined(separator: " ") desc += " )" return desc } } extension Vector { func formatted<F: FormatStyle>(_ style: F) -> String where F.FormatInput == T, F.FormatOutput == String { var desc = "( " desc += values.map { style.format($0) }.joined(separator: " ") desc += " )" return desc } } In the example below, the vector contains a mix of integer and float literals. The result is a vector with a type of Vector<Double>. Since the values of the vector are inferred as Double then I expect the print output to display as decimal numbers. However, the .number formatted output seems to ignore the vector type and print the values as a mix of integers and decimals. This is fixed by explicitly providing a format style with a fraction length. So why is the .formatted(.number) method ignoring the vector type T which is Double in this example? let vec = Vector(values: [-2, 5.5, 100, 19, 4, 8.37]) print(vec) print(vec.formatted(.number)) print(vec.formatted(.number.precision(.fractionLength(1...)))) ( -2.0 5.5 100.0 19.0 4.0 8.37 ) // correct output that uses all Double types ( -2 5.5 100 19 4 8.37 ) // wrong output that uses Int and Double types ( -2.0 5.5 100.0 19.0 4.0 8.37 ) // correct output that uses all Double types
2
0
310
Mar ’25