I'm a novice in RealityKit and ARKit. I'm using ARKit in SwiftUI to show a cube with a number as shown below. import SwiftUI import RealityKit import ARKit struct ContentView : View { var body: some View { return ARViewContainer() } } #Preview { ContentView() } struct ARViewContainer: UIViewRepresentable { typealias UIViewType = ARView func makeUIView(context: UIViewRepresentableContext<ARViewContainer>) -> ARView { let arView = ARView(frame: .zero, cameraMode: .ar, automaticallyConfigureSession: true) arView.enableTapGesture() return arView } func updateUIView(_ uiView: ARView, context: UIViewRepresentableContext<ARViewContainer>) { } } extension ARView { func enableTapGesture() { let tapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(handleTap(recognizer:))) self.addGestureRecognizer(tapGestureRecognizer) } @objc func handleTap(recognizer: UITapGestureRecognizer) { let tapLocation = recognizer.location(in: self) // print("Tap location: \(tapLocation)") guard let rayResult = self.ray(through: tapLocation) else { return } let results = self.raycast(from: tapLocation, allowing: .estimatedPlane, alignment: .any) if let firstResult = results.first { let position = simd_make_float3(firstResult.worldTransform.columns.3) placeObject(at: position) } } func placeObject(at position: SIMD3<Float>) { let mesh = MeshResource.generateBox(size: 0.3) let material = SimpleMaterial(color: UIColor.systemRed, roughness: 0.3, isMetallic: true) let modelEntity = ModelEntity(mesh: mesh, materials: [material]) var unlitMaterial = UnlitMaterial() if let textureResource = generateTextResource(text: "1", textColor: UIColor.white) { unlitMaterial.color = .init(tint: .white, texture: .init(textureResource)) modelEntity.model?.materials = [unlitMaterial] let id = UUID().uuidString modelEntity.name = id modelEntity.transform.scale = [0.3, 0.1, 0.3] modelEntity.generateCollisionShapes(recursive: true) let anchorEntity = AnchorEntity(world: position) anchorEntity.addChild(modelEntity) self.scene.addAnchor(anchorEntity) } } func generateTextResource(text: String, textColor: UIColor) -> TextureResource? { if let image = text.image(withAttributes: [NSAttributedString.Key.foregroundColor: textColor], size: CGSize(width: 18, height: 18)), let cgImage = image.cgImage { let textureResource = try? TextureResource(image: cgImage, options: TextureResource.CreateOptions.init(semantic: nil)) return textureResource } return nil } } I tap the floor and get a cube with '1' as shown below. The background color of the cube is black, I guess. Where does this color come from and how can I change it into, say, red? Thanks.

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.

In reference to this webpage, I'm turning my iPad to an iBeacon device. class BeaconViewModel: NSObject, ObservableObject, CBPeripheralManagerDelegate { private var peripheralManager: CBPeripheralManager? private var beaconRegion: CLBeaconRegion? private var beaconIdentityConstraint: CLBeaconIdentityConstraint? //private var beaconCondition: CLBeaconIdentityCondition? override init() { super.init() if let uuid = UUID(uuidString: "abc") { beaconIdentityConstraint = CLBeaconIdentityConstraint(uuid: uuid, major: 123, minor: 456) beaconRegion = CLBeaconRegion(beaconIdentityConstraint: beaconIdentityConstraint!, identifier: "com.example.myDeviceRegion") peripheralManager = CBPeripheralManager(delegate: self, queue: nil, options: nil) } } func peripheralManagerDidUpdateState(_ peripheral: CBPeripheralManager) { switch peripheral.state { case .poweredOn: startAdvertise() case .poweredOff: peripheralManager?.stopAdvertising() default: break } } func startAdvertise() { guard let beaconRegion = beaconRegion else { return } let peripheralData = beaconRegion.peripheralData(withMeasuredPower: nil) peripheralManager?.startAdvertising(((peripheralData as NSDictionary) as! [String: Any])) } func stopAdvertise() { peripheralManager?.stopAdvertising() } } In Line 10, I'm using CLBeaconidentityConstraint to constrain the beacon. Xcode says that this class is deprecated and suggests that we use CLBeaconIdentityCondition. But if I try to use it, Xcode says Cannot find type 'CLBeaconIdentityCondition' in scope I've just updated Xcode to 16.4. I still get the same error. So how do we use CLBeaconIdentityCondition to constrain the beacon? My macOS version is Sequoia 15.5. Thanks.

I have a macOS application developed in SwiftUI. It's a document-based application. I know how to hide the Show Tab Bar command under View. I don't want to hide it. I always want to show tabs. I wonder how to enable this command programmatically such that the document window always has the + button to the right. Thanks.

I'm working on an iOS app with a Widget. I am able to display the Widget on the iPhone 16 Pro Simulator. It doesn't appear on iPad mini 6th gen., though. Anyway, I want to make sure that it works on an actual device. If I try to add the Widget to the Home Screen, I cannot find it in the search list on iPhone XR and iPad 9th gen. If I set the target to that of the widget, Xcode gives me the following error. SendProcessControlEvent:toPid: encountered an error: Error Domain=com.apple.dt.deviceprocesscontrolservice Code=8 "Failed to show Widget 'some bundle ID' error: … I hope that's not a sign of trouble. So how do you debug a Widget on an Actual Device? I've read some topics like this one here. Thanks.

I have the following lines of code to access data through CoreData. import Foundation import CoreData import CloudKit class CoreDataManager { static let instance = CoreDataManager() let container: NSPersistentCloudKitContainer let context: NSManagedObjectContext init() { container = NSPersistentCloudKitContainer(name: "ABC") container.loadPersistentStores(completionHandler: { (storeDescription, error) in if let error = error as NSError? { print(error.userInfo) } }) context = container.viewContext context.automaticallyMergesChangesFromParent = true context.mergePolicy = NSMergePolicy(merge: .mergeByPropertyObjectTrumpMergePolicyType) } func save() { do { try container.viewContext.save() print("Saved successfully") } catch { print("Error in saving data: \(error.localizedDescription)") } } } I have confirmed that I can share data between iPhone and iPad. Now, I need to use AppGroup as well. I have changed my code as follows. import Foundation import CoreData import CloudKit class CoreDataManager { static let shared = CoreDataManager() let container: NSPersistentContainer let context: NSManagedObjectContext init() { container = NSPersistentCloudKitContainer(name: "ABC") container.persistentStoreDescriptions = [NSPersistentStoreDescription(url: FileManager.default.containerURL(forSecurityApplicationGroupIdentifier: "some group name")!.appendingPathComponent("CoreDataMama.sqlite"))] container.loadPersistentStores(completionHandler: { (description, error) in if let error = error as NSError? { print("Unresolved error \(error), \(error.userInfo)") } }) context = container.viewContext context.automaticallyMergesChangesFromParent = true context.mergePolicy = NSMergePolicy(merge: .mergeByPropertyObjectTrumpMergePolicyType) } func save() { do { try container.viewContext.save() print("Saved successfully") } catch { print("Error in saving data: \(error.localizedDescription)") } } } Other files being unaltered, my sample apps aren't sharing data. What am I doing wrong? Just FYI, I'm using actual devices. Thank you for your reading this topic.

I need to check the network connection with NWPathMonitor. import Foundation import Network class NetworkViewModel: ObservableObject { let monitor = NWPathMonitor() let queue = DispatchQueue(label: "NetworkViewModel") @Published var isConnected = false var connectionDescription: String { if isConnected { return "You are connected." } else { return "You are NOT connected." } } init() { monitor.pathUpdateHandler = { path in DispatchQueue.main.async { self.isConnected = path.status == .satisfied } } monitor.start(queue: queue) } } import SwiftUI struct ContentView: View { @StateObject private var networkViewModel = NetworkViewModel() var body: some View { VStack { } .onAppear { if networkViewModel.isConnected { print("You are connected.") } else { print("You are NOT connected.") } } } } So there is nothing special, not at all. Yet, if I test it with a totally new Xcode project for iOS, it fails and return !isConnected. I've tested it with a macOS application. And it fails. I've tested it with an actual device. It fails. I've tested it with an old project. It still does work. I have no mere idea why new Xcode projects all fail to detect the WiFi connection. This is a total nightmare. Does anybody have a clue? thanks.

I have a SwiftUI app. It fetches records through CoreData. And I want to show some records on a widget. I understand that I need to use AppGroup to share data between an app and its associated widget. import Foundation import CoreData import CloudKit class DataManager { static let instance = DataManager() let container: NSPersistentContainer let context: NSManagedObjectContext init() { container = NSPersistentCloudKitContainer(name: "DataMama") container.persistentStoreDescriptions = [NSPersistentStoreDescription(url: FileManager.default.containerURL(forSecurityApplicationGroupIdentifier: group identifier)!.appendingPathComponent("Trash.sqlite"))] container.loadPersistentStores(completionHandler: { (description, error) in if let error = error as NSError? { print("Unresolved error \(error), \(error.userInfo)") } }) context = container.viewContext context.automaticallyMergesChangesFromParent = true context.mergePolicy = NSMergePolicy(merge: .mergeByPropertyObjectTrumpMergePolicyType) } func save() { do { try container.viewContext.save() print("Saved successfully") } catch { print("Error in saving data: \(error.localizedDescription)") } } } // ViewModel // import Foundation import CoreData import WidgetKit class ViewModel: ObservableObject { let manager = DataManager() @Published var records: [Little] = [] init() { fetchRecords() } func fetchRecords() { let request = NSFetchRequest<Little>(entityName: "Little") do { records = try manager.context.fetch(request) records.sort { lhs, rhs in lhs.trashDate! < rhs.trashDate! } } catch { print("Fetch error for DataManager: \(error.localizedDescription)") } WidgetCenter.shared.reloadAllTimelines() } } So I have a view model that fetches data for the app as shown above. Now, my question is how should my widget get data from CoreData? Should the widget get data from CoreData through DataManager? I have read some questions here and also read some articles around the world. This article ( https://dev.classmethod.jp/articles/widget-coredate-introduction/ ) suggests that you let the Widget struct access CoreData through DataManager. If that's a correct fashion, how should the getTimeline function in the TimelineProvider struct get data? This question also suggests the same. Thank you for your reading my question.

Its document says openDocument can open a document at a specific URL. So I've saved a model as a JSON object with its URL and a bookmark as Data. With its security-scoped bookmark data resolved, I am able to open a document except that the app will crash right after opening a document. Console says should only be called in the main thread struct ContentView: View { @EnvironmentObject var bookmarkViewModel: BookmarkViewModel var body: some View { VStack { } .onAppear { loadBookmarks() } } extension ContentView { func loadBookmarks() { print("1 \(Thread.current)") // NSMainThread Task { for bookmarkItem in bookmarkViewModel.bookmarkItems { // resolving a security-scoped bookmark print("2 \(Thread.current)") // NSMainThread if let _ = resolveBookmark(bookmarkData: bookmarkItem.bookmarkData) { print("3 \(Thread.current)") // NSMainThread do { print("4 \(Thread.current)") // NSMainThread try await openDocument(at: bookmarkItem.bookmarkURL) print("5 \(Thread.current)") // NSMainThread } catch { print("\(error.localizedDescription)") } } } } } } Well, the application is on the main thread. I've checked every line before and after opening a document with its URL. Call what on the main thread? This is confusing. Thanks. class BookmarkViewModel: ObservableObject { @Published var bookmarkItems: [BookmarkItem] = [] var defaultFileManager: FileManager { return FileManager.default } var documentURL: URL? { ... } init() { fetchBookmarkItems() } func fetchBookmarkItems() { bookmarkItems.removeAll() if let documentURL { let bookmarkFolderURL = documentURL.appending(path: "MyApp").appending(path: "Bookmarks") do { let contents = try defaultFileManager.contentsOfDirectory(atPath: bookmarkFolderURL.path) for content in contents { ... let fileURL = bookmarkFolderURL.appending(path: content) let data = try Data(contentsOf: fileURL) let bookmarkItem = try JSONDecoder().decode(BookmarkItem.self, from: data) bookmarkItems.append(bookmarkItem) } } catch { print("Error fetching folder content: \(error.localizedDescription)") } } } } struct BookmarkItem: Codable, Hashable { let bookmarkURL: URL let date: Date let bookmarkData: Data let open: Bool }

I have a simple document-based application for macOS. struct ContentView: View { @Binding var document: TextDocument var body: some View { .onReceive(NotificationCenter.default.publisher(for: .notificationTextWillAppendSomeTextt), perform: { _ in }) VStack { TextEditor(text: $document.text) } } } extension Notification.Name { static let notificationTextWillAppendSomeTextt = Notification.Name("TextWillAppendSomeText") } Suppose that my application currently has three tabs. If I call a menu command through post(name:object:) this menu command call will affect all three of them. This stackoverflow topic talks about it, too. So how could I tell which window should get a call and others don't? Thanks.

I have a sample document-based macOS app. I understand that you can open a new window or a new tab with some text. import SwiftUI struct ContentView: View { @Binding var document: TexDocument @Environment(\.newDocument) var newDocument var body: some View { VStack(spacing: 0) { topView } } private var topView: some View { Button { newDocument(TexDocument(text: "A whole new world!")) } label: { Text("Open new window") .frame(width: 200) } } } Suppose that I have a path to a text file whose security-scoped bookmark can be resolved with a click of a button. I wonder if you can open a new window or a new tab with the corresponding content?. I have done that in Cocoa. I hope I can do it in SwiftUI as well. Thanks.

I have a sample document-based application for macOS. According to this article (https://jujodi.medium.com/adding-a-new-tab-keyboard-shortcut-to-a-swiftui-macos-application-56b5f389d2e6), you can create a new tab programmatically. It works. Now, my question is whether you can open a tab with some data. Is that possible under the SwiftUI framework? I could do it in Cocoa. Hopefully, we can do it in SwiftUI as well. Muchos thankos. import SwiftUI @main struct SomeApp: App { var body: some Scene { DocumentGroup(newDocument: SomeDocument()) { file in ContentView(document: file.$document) } } } import SwiftUI struct ContentView: View { @Binding var document: SomeDocument var body: some View { VStack { TextEditor(text: $document.text) Button { createNewTab() } label: { Text("New tab") .frame(width: 64) } } } } extension ContentView { private func createNewTab() { if let currentWindow = NSApp.keyWindow, let windowController = currentWindow.windowController { windowController.newWindowForTab(nil) if let newWindow = NSApp.keyWindow, currentWindow != newWindow { currentWindow.addTabbedWindow(newWindow, ordered: .above) } } } }

I'm playing with a simple document-based application with TextEditor for macOS. In Cocoa, NSViewController can call updateChangeCount(_:) to clear document changes in NSDocument. I wonder SwiftUI's View has access to the same function? Hopefully, I would like to manually set the change count to zero if the user clears text in TextEditor. I bet SwiftUI doesn't have it. Thanks. import SwiftUI struct ContentView: View { @Binding var document: SampleDocumentApp var body: some View { VStack { TextEditor(text: $document.text) .onChange(of: document.text) { _, _ in guard !document.text.isEmpty else { return } // clear change count // } } .frame(width: 360, height: 240) } }

I have developed several document-based (NSDocument) applications for macOS is Cocoa. Now, I'm playing with a document app project in SwiftUI. If I launch the application out of box, a file-select panel will open just as you see in TextEdit. (Please see the picture below) How do we prevent it from appearing? I would rather show a blank window, which in fact appears if I just press Command + N. Thanks.

I have a simple SwiftUI project with two basic build configurations (Debug, Release) as shown below. I now choose Build > Scheme > Edit Scheme under Product and select Release as the current build configuration as shown below. And the Preview canvas exhibit errors. If I click on the Diagnostics button, it says under PREVIEW UPDATE ERROR OptimizationLevelError: not building -Onone ”BuildSchemeCrazyDaughter.app” needs -Onone Swift optimization level to use previews (current setting is -O) What does that mean and why don't I get the preview for the Release build configuration? Thanks.