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Swift/objC combined with Swift/C++ interop
Consider this Swift struct: public struct Example { public func foo(callback: ()->Void) { .... } public func blah(i: Int) { .... } .... } Using Swift/C++ interop, I can create Example objects and call methods like blah. But I can't call foo because Swift/C++ interop doesn't currently support passing closures (right?). On the other hand, Swift/objC does support passing objC blocks to Swift functions. But I can't use that here because Example is a Swift struct, not a class. So I could change it to a class, and update everything to work with reference rather than value semantics; but then I also have to change the objC++ code to create the object and call its methods using objC syntax. I'd like to avoid that. Is there some hack that I can use to make this possible? I'm hoping that I can wrap a C++ std::function in some sort of opaque wrapper and pass that to swift, or something. Thanks for any suggestions!
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681
Jan ’25
HealthKit permissions not honoring user selection
I'm dealing with a strange bug where I am requesting read access for 'appleExerciseTime' and 'activitySummaryType', and despite enabling both in the permission sheet, they are being set to 'sharingDenied'. I'm writing a Swift Test for making sure permissions are being granted. @Test func PermissionsGranted() { try await self.manager.getPermissions() for type in await manager.allHealthTypes { let status = await manager.healthStore.authorizationStatus(for: type) #expect(status == .sharingAuthorized, "\(type) authorization status is \(status)") } } let healthTypesToShare: Set<HKSampleType> = [ HKQuantityType(.bodyMass), HKQuantityType(.bodyFatPercentage), HKQuantityType(.leanBodyMass), HKQuantityType(.activeEnergyBurned), HKQuantityType(.basalEnergyBurned), HKObjectType.workoutType() ] let allHealthTypes: Set<HKObjectType> = [ HKQuantityType(.bodyMass), HKQuantityType(.bodyFatPercentage), HKQuantityType(.leanBodyMass), HKQuantityType(.activeEnergyBurned), HKQuantityType(.basalEnergyBurned), HKQuantityType(.appleExerciseTime), HKObjectType.activitySummaryType() ] let healthStore = HKHealthStore() func getPermissions() async throws { try await healthStore.requestAuthorization(toShare: self.healthTypesToShare, read: self.allHealthTypes) } After 'getPermissions' runs, the permission sheet shows up on the Simulator, and I accept all. I've double checked that the failing permissions show up on the sheet and are enabled. Then the test fails with: Expectation failed: (status → HKAuthorizationStatus(rawValue: 1)) == (.sharingAuthorized → HKAuthorizationStatus(rawValue: 2)) HKActivitySummaryTypeIdentifier authorization status is HKAuthorizationStatus(rawValue: 1) Expectation failed: (status → HKAuthorizationStatus(rawValue: 1)) == (.sharingAuthorized → HKAuthorizationStatus(rawValue: 2)) HKActivitySummaryTypeIdentifier authorization status is HKAuthorizationStatus(rawValue: 1) With the rawValue of '1' being 'sharingDenied'. All other permissions are granted. Is there a workaround here, or something I'm potentially doing wrong?
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977
Jan ’25
How to save a point cloud in the sample code "Capturing depth using the LiDAR camera" with the photoOutput
Hello dear community, I have the sample code from Apple “CapturingDepthUsingLiDAR” to access the LiDAR on my iPhone 12 Pro. My goal is to use the “photo output” function to generate a point cloud from a single image and then save it as a ply file. So far I have tested different approaches to create a .ply file from the depthmap, the intrinsic camera data and the rgba values. Unfortunately, I have had no success so far and the result has always been an incorrect point cloud. My question now is whether there are already approaches to this and whether anyone has any experience with it. Thank you very much in advance!!!
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528
Jan ’25
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?
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546
Jan ’25
NSExpression error handling
Context: SwiftUI TextField with a String for simple math using NSExpression. I first prepare the input string to an extent but a malformed input using valid characters still fails, as expected. Let's say preparedExpression is "5--" let expr = NSExpression(format: preparedExpression) gives FAULT: NSInvalidArgumentException: Unable to parse the format string "5-- == 1"; (user info absent) How can I use NSExpression such that either the preparedExpression is pre-tested before asking for actual execution or the error is handled in a polite way that I can use to alert the user to try again. Is there a Swift alternative to NSExpression that I've missed?
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531
Jan ’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.
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500
Feb ’25
Why doesn’t getAPI() show up in autocomplete despite having a default implementation in a protocol extension?
I’m working on a project in Xcode 16.2 and encountered an issue where getAPI() with a default implementation in a protocol extension doesn’t show up in autocomplete. Here’s a simplified version of the code: import Foundation public protocol Repository { func getAPI(from url: String?) } extension Repository { public func getAPI(from url: String? = "https://...") { getAPI(from: url) } } final class _Repository: Repository { func getAPI(from url: String?) { // Task... } } let repo: Repository = _Repository() repo.getAPI( // Autocomplete doesn't suggest getAPI() I’ve tried the following without success: • Clean build folder • Restart Xcode • Reindexing Is there something wrong with the code, or is this a known issue with Xcode 16.2? I’d appreciate any insights or suggestions.
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617
Jan ’25
Returning One Component of Struct as Encoded Value in JSON
I have a class that I want to custom encode into JSON: class Declination: Decodable, Encodable { var asString: String var asDouble: Double init(_ asString: String) { self.asString = asString self.asDouble = raToDouble(asString) } required init(from decoder: Decoder) throws { let value = try decoder.singleValueContainer() self.asString = try value.decode(String.self) self.asDouble = declinationToDouble(asString) } } As you can see, I calculate the double form of the declination when I decode a JSON file containing the data. What I want to do now is ENCODE the class back out as a single string. Currently the standard JSON encode in Swift produces the following: "declination":{"asDouble":18.26388888888889,"asString":"+18:15:50.00"} what I want to produce is: declination:"+18:15:50.00" How can I easily do that? I've read up about custom encoders and such, and I get confused about the containers and what keys are being used. I think there might be a simple answer where I could just code: extension Coordinate: Encodable { func encode(to encoder: Encoder) throws { return encoder.encode(self.asString) } } But experienced Swift developers will immediately see that won't work. Should I do JSONSerialization instead? Can I just write a toString() extension and have JSON pick that up? Any help would be appreciated. Thanks, Robert
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334
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?
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639
Jan ’25
Best way to learn Swift
Hi I'm new here - I'm trying to learn Swift and SwiftUI. Tried on PluralSight and Udemy but they have been outdated and thus hard to follow. So after finding Apples own guides I felt relieved and happy, but now I'm stuck again. After they've updated Xcode to use #Preview instead of PreviewProvider it's hard to follow along on their tutorial. Does anyone know of good resources to study SwiftUI? Or know if apple plan to update their tutorials any time soon? I'm here now if anyone's interested or it's useful information: https://developer.apple.com/tutorials/app-dev-training/managing-state-and-life-cycle
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420
Feb ’25
array.contains(where: ...) returns true in debugger console, but false in application
I am encountering a strange issue. I have a class that manages a selection of generic items T in an Array. It's a work in progress, but I'l try to give a gist of the setup. class FileManagerItemModel: NSObject, Identifiable, Codable, NSCopying, Transferable, NSItemProviderReading, NSItemProviderWriting { var id: URL static func == (lhs: FileManagerItemModel, rhs: FileManagerItemModel) -> Bool { lhs.fileURL == rhs.fileURL } var fileURL: URL { FileManagerItemModel.normalizedFileURL(type: type, rootURL: rootURL, filePath: filePath) } init(type: FileManagerItemType, rootURL: URL, fileURL: URL) { self.type = type self.rootURL = rootURL self.filePath = FileManagerItemModel.filePathRelativeToRootURL(fileURL: fileURL, rootURL: rootURL) ?? "[unknown]" self.id = FileManagerItemModel.normalizedFileURL(type: type, rootURL: rootURL, filePath: filePath) } } The class that manages the selection of these FileManagerItemModels is like so: @Observable class MultiSelectDragDropCoordinator<T: Hashable>: ObservableObject, CustomDebugStringConvertible { private(set) var multiSelectedItems: [T] = [] func addToSelection(_ item: T) { if !multiSelectedItems.contains(where: { $0 == item }) { multiSelectedItems.append(item) } } ... } My issue is that the check if !multiSelectedItems.contains(where: { $0 == item }) in func addToSelection fails. The if is always executed, even if multiSelectedItems contains the given item. Now, my first thought would be to suspect the static func == check. But that check works fine and does what it should do. Equality is defined by the whole fileURL. So, the if should have worked. And If I put a breakpoint in func addToSelection on the if, and type po multiSelectedItems.contains(where: { $0 == item }) in the debug console, it actually returns true if the item is in multiSelectedItems. And it properly return false if the item is not in multiSelectedItems. Still, if I then continue stepping through the app after the breakpoint was hit and I confirmed that the contains should return true, the app still goes into the if, and adds a duplicate item. I tried assigning to a variable, I tried using a function and returning the true/false. Nothing helps. Does anyone have an idea on why the debugger shows one (the correct and expected) thing but the actual code still does something different?
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558
Feb ’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?
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503
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 :-)
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452
Feb ’25
Hash Collision in Data type
I notice that Swift Data type's hashValue collision when first 80 byte of data and data length are same because of the Implementation only use first 80 bytes to compute the hash. https://web.archive.org/web/20120605052030/https://opensource.apple.com/source/CF/CF-635.21/CFData.c also, even if hash collision on the situation like this, I can check data is really equal or not by == does there any reason for this implementation(only use 80 byte of data to make hashValue)? test code is under below let dataArray: [UInt8] = [ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 ] var dataArray1: [UInt8] = dataArray var dataArray2: [UInt8] = dataArray dataArray1.append(contentsOf: [0x00, 0x00, 0x00, 0x00]) dataArray2.append(contentsOf: [0xff, 0xff, 0xff, 0xff]) let data1 = Data(dataArray1) let data2 = Data(dataArray2) // Only last 4 byte differs print(data1.hashValue) print(data2.hashValue) print(data1.hashValue == data2.hashValue) // true print(data1 == data2) // false
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578
Feb ’25
Implementing RawRepresentable for a DictionaryType has broken my Test target build. Not sure how to fix things...
For my app I've created a Dictionary that I want to persist using AppStorage In order to be able to do this, I added RawRepresentable conformance for my specific type of Dictionary. (see code below) typealias ScriptPickers = [Language: Bool] extension ScriptPickers: @retroactive RawRepresentable where Key == Language, Value == Bool { public init?(rawValue: String) { guard let data = rawValue.data(using: .utf8), let result = try? JSONDecoder().decode(ScriptPickers.self, from: data) else { return nil } self = result } public var rawValue: String { guard let data = try? JSONEncoder().encode(self), // data is Data type let result = String(data: data, encoding: .utf8) // coerce NSData to String else { return "{}" // empty Dictionary represented as String } return result } } public enum Language: String, Codable, { case en = "en" case fr = "fr" case ja = "ja" case ko = "ko" case hr = "hr" case de = "de" } This all works fine in my app, however trying to run any tests, the build fails with the following: Conflicting conformance of 'Dictionary<Key, Value>' to protocol 'RawRepresentable'; there cannot be more than one conformance, even with different conditional bounds But then when I comment out my RawRepresentable implementation, I get the following error when attempting to run tests: Value of type 'ScriptPickers' (aka 'Dictionary<Language, Bool>') has no member 'rawValue' I hope Joseph Heller is out there somewhere chuckling at my predicament any/all ideas greatly appreciated
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581
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.
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488
Feb ’25
Dateformatter returns date in incorrect format
I have configured DateFormatter in the following way: let df = DateFormatter() df.dateFormat = "yyyy-MM-dd'T'HH:mm:ss'Z'" df.locale = .init(identifier: "en") df.timeZone = .init(secondsFromGMT: 0) in some user devices instead of ISO8601 style it returns date like 09/25/2024 12:00:34 Tried to change date format from settings, changed calendar and I think that checked everything that can cause the problem, but nothing helped to reproduce this issue, but actually this issue exists and consumers complain about not working date picker. Is there any information what can cause such problem? May be there is some bug in iOS itself?
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433
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
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551
Feb ’25
How to convert a function into a variable?
Hello, I have a test variable here which works fine: var quotes: [(quote: String, order: Int)] = [ ("I live you the more ...", 1), ("There is nothing permanent ...", 2), ("You cannot shake hands ...", 3), ("Lord, make me an instrument...", 4) ] and I have a test function which successfully pulls data from a mysql database via a web service and displays it via the "print" function: func getPrice(){ if let url = URL(string:"https://www.TEST.com/test_connection.php"){ URLSession.shared.dataTask(with: url) { (data, response, error) in if let data = data{ if let json = try? JSONDecoder().decode([[String:String]].self, from: data){ json.forEach { row in print(row["quote"]!) print(row["order"]!) } } else{ } } else{ print("wrong :-(") } }.resume() } } Please can you tell me how to re-write the quotes variable/array so that it returns the results that are found in the getPrice() function?
3
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458
Mar ’25