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.

I have a sample SwiftUI iOS app. As shown in the screenshot below, my project has three configurations: Debug, MyDebug, Release. If I select the Debug or MyDebug scheme, I get a preview. But if I select the Release scheme, I get an error that says the following. ”***.app” needs -Onone Swift optimization level to use previews (current setting is -O) , where *** is the app name. It probably has nothing to do with the Preview error, but the Info.plist has a dictionary such that the key name is devMode, and the value is $(DEVMODE). And I have a user-defined setting as shown below. My ContentView has the following. import SwiftUI struct ContentView: View { @State private var state: String = "" var body: some View { VStack { Text("Hello, world!: \(state)") } .onAppear { if let devMode = Bundle.main.object(forInfoDictionaryKey: "devMode") as? String { print("Development mode: \(devMode)") state = devMode } if let path = Bundle.main.path(forResource: "Info", ofType: "plist") { if let dict = NSDictionary(contentsOfFile: path) { print("**** \(dict)") } } #if DEBUG print("Debug") #elseif MYDEBUG print("MyDebug") #else print("Que?") #endif } } } #Preview { ContentView() } So my question is how I get the preview for all three build schemes? Muchos thankos.

I have a very cheap Bluetooth-connected printer. And I want to print out a word or two via Core Bluetooth. It's an iOS app with the SwiftUI framework. The following is what I have for an ObservableObject class. import Foundation import CoreBluetooth class BluetoothManager: NSObject, ObservableObject, CBCentralManagerDelegate, CBPeripheralDelegate { @Published var connectedDevices: [CBPeripheral] = [] @Published var powerOn = false @Published var peripheralConnected = false private var centralManager: CBCentralManager! private var peripheralName = "LX-D02" private var connectedPeripheral: CBPeripheral? private var writeCharacteristic: CBCharacteristic? private let serviceUUID = CBUUID(string:"5833FF01-9B8B-5191-6142-22A4536EF123") private let characteristicUUID = CBUUID(string: "FFE1") override init() { super.init() self.centralManager = CBCentralManager(delegate: self, queue: nil) } func startScanning() { if centralManager.state == .poweredOn { centralManager.scanForPeripherals(withServices: nil, options: nil) } } func centralManagerDidUpdateState(_ central: CBCentralManager) { if central.state == .poweredOn { powerOn = true print("Bluetooth is powered on") } else { print("Bluetooth is not available") } } func centralManager(_ central: CBCentralManager, didDiscover peripheral: CBPeripheral, advertisementData: [String : Any], rssi RSSI: NSNumber) { if !connectedDevices.contains(peripheral) { if let localName = advertisementData["kCBAdvDataLocalName"] as? String { if localName == peripheralName { connectedDevices.append(peripheral) centralManager.connect(peripheral, options: nil) centralManager.stopScan() peripheralConnected = true print("Connected: \(peripheral.identifier.uuidString)") } } } } func centralManager(_ central: CBCentralManager, didConnect peripheral: CBPeripheral) { connectedPeripheral = peripheral peripheral.delegate = self let services = [serviceUUID] peripheral.discoverServices(services) //discoverServices(peripheral: peripheral) } func centralManager(_ central: CBCentralManager, didFailToConnect peripheral: CBPeripheral, error: (any Error)?) { guard let error = error else { print("Failed connection unobserved") return } print("Error: \(error.localizedDescription)") } func peripheral(_ peripheral: CBPeripheral, didDiscoverServices error: Error?) { if let error = error { print("Failing to discover servies: \(error.localizedDescription)") return } discoverCharacteristics(peripheral: peripheral) } /* Return all available services */ private func discoverServices(peripheral: CBPeripheral) { peripheral.discoverServices(nil) } private func discoverCharacteristics(peripheral: CBPeripheral) { guard let services = peripheral.services else { return } for service in services { peripheral.discoverCharacteristics(nil, for: service) } } func peripheral(_ peripheral: CBPeripheral, didDiscoverCharacteristicsFor service: CBService, error: Error?) { guard let characteristics = service.characteristics else { return } for characteristic in characteristics { let characteristicUUID = characteristic.uuid print("Discovered characteristic: \(characteristicUUID)") peripheral.setNotifyValue(true, for: characteristic) if characteristic.properties.contains(.writeWithoutResponse) { writeCharacteristic = characteristic print("You can write!!!") // Never read... } if characteristic.properties.contains(.write) { print("You can write?") writeCharacteristic = characteristic // Being read... } } func writeToPrinter() { guard let peripheral = connectedPeripheral else { print("Ughhh...") return } if let characteristic = writeCharacteristic { if let data = "Hello".data(using: .utf8, allowLossyConversion: true) { peripheral.writeValue(data, for: characteristic, type: .withoutResponse) peripheral.writeValue(data, for: characteristic, type: .withResponse) // -> Message sent successfully } } } func peripheral(_ peripheral: CBPeripheral, didWriteValueFor characteristic: CBCharacteristic, error: Error?) { if let error = error { print("Writing error: \(error.localizedDescription)") return } print("Message sent successfully") } } My app has no trouble connecting to the bluetooth-connected printer. Initially, I called discoverServices(peripheral:) to get all services And I get a service identifier (5833FF01-9B8B-5191-6142-22A4536EF123) for my printer. peripheral(_:didDiscoverCharacteristicsFor:error:) doesn't return a thing for .writeWithoutResponse but does return a characteristic for .write. Eventually, if I call writeToPrinter(), peripheral.writeValue(data, for: characteristic, type: .withoutResponse) returns WARNING: Characteristic <CBCharacteristic: 0x3019040c0, UUID = 5833FF02-9B8B-5191-6142-22A4536EF123, properties = 0x8, value = (null), notifying = NO> does not specify the "Write Without Response" property - ignoring response-less write If I call peripheral.writeValue(data, for: characteristic, type: .withResponse) , there is no error. But I get no output from the printer. What am I doing wrong? Thanks.

I have the following lines of code where I show a bunch of checkboxes, each of which can toggle between on and off with a tap. import SwiftUI struct ContentView: View { @State private var viewModel = ContentViewModel() var body: some View { VStack(alignment: .leading) { List { ForEach(viewModel.models, id: \.id) { model in CheckButtonView(id: model.id, text: model.name, isOn: model.isOn) { id, bool in updateDate(id: id, bool: bool) } } } } } func updateDate(id: String, bool: Bool) { for i in 0..<viewModel.models.count { let oldModel = viewModel.models[i] if oldModel.id == id { let newModel = Content(id: oldModel.id, name: oldModel.name, isOn: bool) viewModel.models.remove(at: i) viewModel.models.insert(newModel, at: i) break } } var count = 0 for i in 0..<viewModel.models.count { let model = viewModel.models[i] if model.isOn { count += 1 } } } } struct CheckButtonView: View { let id: String let text: String @State var isOn: Bool var callBack: (String, Bool) -> Void var body: some View { HStack { Button { isOn.toggle() callBack(id, isOn) } label: { Image(systemName: isOn ? "checkmark.square.fill" : "square") .resizable() .aspectRatio(contentMode: .fit) .frame(width: 18) .tint(!isOn ? .black : .blue) } Text(text) .font(.subheadline) Spacer() } .frame(maxWidth: .infinity) } } struct Content { let id: String let name: String let isOn: Bool } class ContentViewModel: ObservableObject { @Published var models = [Content]() @Published var canChange = true init() { models = [ Content(id: UUID().uuidString, name: "Jim", isOn: false), Content(id: UUID().uuidString, name: "Jenny", isOn: false), Content(id: UUID().uuidString, name: "Nancy", isOn: false), Content(id: UUID().uuidString, name: "Natalie", isOn: false) ] } } According to the picture above, I have two checkboxes that are turned on. Now, what I want to do is let the user turn on as many as two checkboxes only. Can someone think of a good way of doing that? Thanks.

I have an NSStatusBar application. This is my first in SwiftUI. And I need to know when the window is closed so that I can disable some of menu commands. I can use NSWindowDelegate with AppDelegate as follows. import SwiftUI @main struct SomeApp: App { @NSApplicationDelegateAdaptor(AppDelegate.self) var appDelegate @StateObject private var menuViewModel = MenuViewModel() var body: some Scene { WindowGroup { ContentView() .environmentObject(menuViewModel) } } } class AppDelegate: NSObject, NSApplicationDelegate, NSWindowDelegate { private var menuViewModel = MenuViewModel() func applicationDidFinishLaunching(_ notification: Notification) { if let window = NSApplication.shared.windows.first { window.setIsVisible(false) window.delegate = self } } func windowWillClose(_ notification: Notification) { menuViewModel.windowClosed = true } } When the window will close, MenuViewModel (ObservableObject) will receive a call, which I want my ContentView to receive. But, so far, it won't. import SwiftUI struct ContentView: View { var body: some View { ZStack { ... ... } .onReceive(statusBarViewModel.$windowClosed) { result in // never called... } } } Can a SwiftUI View receive a call somehow when its window closes? Muchos thankos.

I see a lot of tutorials that show how to open a SwiftUI View when a NSStatusItem is clicked on. That's not what I want. I need to show a SwiftUI View when I click on a button over SwiftUI View. So far the following is what I have. import SwiftUI @main struct MyStatusApp_App: App { @NSApplicationDelegateAdaptor(AppDelegate.self) var appDelegate var body: some Scene { WindowGroup { ContentView() } } } #if os(macOS) class AppDelegate: NSObject, NSApplicationDelegate { var statusItem: NSStatusItem! private var popover: NSPopover? func applicationDidFinishLaunching(_ notification: Notification) { hideTitleBar() NSApp.setActivationPolicy(.accessory) statusItem = NSStatusBar.system.statusItem(withLength: NSStatusItem.variableLength) if let button = statusItem.button { if let image = NSImage(named: "statusImage") { button.image = image } } } #endif // ContentView // import SwiftUI struct ContentView: View { @NSApplicationDelegateAdaptor(AppDelegate.self) var appDelegate var body: some View { VStack { Button("Click me!") { let popOver = NSPopover() popOver.contentViewController = NSHostingController(rootView: NotificationView()) appDelegate.statusItem = NSStatusBar.system.statusItem(withLength: NSStatusItem.variableLength) if let statusBarbutton = appDelegate.statusItem.button { popOver.show(relativeTo: statusBarbutton.bounds, of: statusBarbutton, preferredEdge: .minY) } } } .frame(width: 200, height: 100) } } If I run the application and click on the button (orange arrow) over ContentView, a guy from NotificationView will appear (green rectangle). That's good. But it appears not below the status item (red arrow). It's positioned at an odd location. It's way below the status item guy. What am I doing wrong? Muchos thankos. I guess site's add image function is broken. It doesn't show my screenshot. ![]("https://developer.apple.com/forums/content/attachment/7e19bf2e-439d-4ed0-a03c-740b77e94e24" "title=Screenshot.jpg;width=364;height=400")