You change center before bottom .alignmentGuide(VerticalAlignment.center) { dim in dim[.top] // re-assign center to 0 } .alignmentGuide(VerticalAlignment.top) { dim in dim[.bottom] } .alignmentGuide(VerticalAlignment.bottom) { dim in dim[VerticalAlignment.center] // 0 } In order to avoid mutual dependence, center value can not be used when calculating bottom. .alignmentGuide(VerticalAlignment.bottom) { dim in dim.height / 2 }

let publisher = $count .receive(on: DispatchQueue.main) // receive in the main thread .map { String(describing: $0) } .removeDuplicates()

ZStack(alignment: .bottom) { ..... let isVisible = isVisible // Remove isolation bottomSheetView .alignmentGuide(VerticalAlignment.bottom) { dimension in isVisible ? dimension[.bottom] : dimension[.top] } } or .alignmentGuide(VerticalAlignment.bottom) { dimension in _isVisible.wrappedValue ? dimension[.bottom] : dimension[.top] }

func hide() { title = "" message = "" percentage = 0 withAnimation { isShowing = false } }

https://developer.apple.com/forums/thread/770971?answerId=818590022#818590022

The problem is similar to the one described at https://forums.developer.apple.com/forums/thread/719521, where onAppear is triggered unexpectedly. The following patterns can currently be summarized: The navigation container must be within a conditional branch. The navigation container needs to perform certain operations (such as entering a new navigation page or creating multiple navigation container instances). Unexpected calls occur when switching to a branch that does not include the navigation container. This issue occurs only in iOS. I have submitted feedback as well. Details can be found here: https://fatbobman.com/en/posts/traps-and-countermeasures-for-abnormal-onappear-calls-in-swiftui/

I adjusted the code to the following form to better reflect the problem of onChange in a multi-layer nested navigation hierarchy. class ViewModel: ObservableObject { @Published var count = 0 } struct Root: View { @StateObject private var viewModel = ViewModel() var body: some View { NavigationStack { SubView(level: 1) .navigationDestination(for: Int.self) { value in SubView(level: value) } } .environmentObject(viewModel) } } struct SubView: View { let level: Int @EnvironmentObject var viewModel: ViewModel var body: some View { VStack { let _ = print("level \(level) Update: \(viewModel.count)") Text("Level: \(level)") Text("Count: \(viewModel.count)") Button("Count++") { viewModel.count += 1 } NavigationLink(value: level + 1) { Text("Goto New Level") } } .task(id: viewModel.count) { print("Level \(level) onTaskID: \(viewModel.count)") } .onChange(of: viewModel.count){ _ in print("Level \(level) onChange: \(viewModel.count)") } .onReceive(viewModel.$count){ _ in print("Level \(level) onReceive: \(viewModel.count)") } } } Clicking "Goto New Level" will add a level, and clicking "Count++" will increase the count value by one When the navigation exceeds 2 levels, only the bottom and top onChange closures will respond No matter how many levels of navigation there are, only the top task(id:) will respond No matter how many levels of navigation there are, onReceive at each level will respond Not sure if this is intentional or a bug, I will submit a feedback to Apple later

change WritableKeyPath to ReferenceWritableKeyPath https://fatbobman.com/en/posts/comprehensive-guide-to-mastering-keypath-in-swift/#writablekeypath-vs-referencewritablekeypath

I attempted to create a model by directly accessing the Managed Object Model (MOM), and the code ran successfully. I also completed the migration process. The implementation is somewhat obscure, and I believe Apple's main purpose in providing this migration method for Core Data is to offer a foundational implementation for phased migrations in SwiftData. guard let momdURL = Bundle.main.url(forResource: "Model", withExtension: "momd") else { fatalError() } let model1URL = momdURL.appending(component: "Model.mom") let model2URL = momdURL.appending(component: "Model 2.mom") guard let model1 = NSManagedObjectModel(contentsOf: model1URL) else { fatalError() } guard let model2 = NSManagedObjectModel(contentsOf: model2URL) else { fatalError() } let v1ModelChecksum = model1.versionChecksum let v1ModelReference = NSManagedObjectModelReference(model: model1, versionChecksum: v1ModelChecksum) let v2ModelChecksum = model2.versionChecksum let v2ModelReference = NSManagedObjectModelReference(model: model2, versionChecksum: v2ModelChecksum) let customStage = NSCustomMigrationStage( migratingFrom: v1ModelReference, to: v2ModelReference ) let migrationManager = NSStagedMigrationManager([customStage]) let description = container.persistentStoreDescriptions.first description?.setOption(migrationManager, forKey: NSPersistentStoreStagedMigrationManagerOptionKey) and I have update my topic about staged migration of Core Data. https://fatbobman.com/en/posts/what-s-new-in-core-data-in-wwdc23

This should be a bug. By using SwiftDataKit to inspect the information of NSPersistentStoreCoordinator, I found that only the store corresponding to the first configuration is loaded. // ModelContainer(for: Schema([Item.self,Tag.self]), configurations: [configuration2,configuration1]) let coordinator = context.coordinator print(coordinator?.persistentStores.count) // 1 Interestingly, SwiftData creates a separate sqlite file for each configuration. I suppose this has already been reported to Feedback, and now we can only wait for Apple to resolve this issue.

func query(group: Group) { let id = group.id let predicate = #Predicate<Item> { item in item.group?.id == id // Compiles } } @MarcusAurelius This method can indeed compile, but when I use similar code to run, the following error message will appear: Thread 1: Fatal error: Couldn't find \Tag.id on Tag with fields May I ask if your code can use the above predicate to fetch data?

Thank you for your reply. However, in some cases, I need to prepare some predicates in advance and combine them according to some conditions during the running of the app. This is also the main use of NSCompoundPredicate in this situation. However, in the new Predicate, no similar mechanism is provided. I feel that PredicateExpression may provide a corresponding method, but I haven't found it yet.

@ModelActor actor CountryModelActor { init(container: ModelContainer) { modelContainer = container let context = ModelContext(container) modelExecutor = DefaultSerialModelExecutor(modelContext: context) } func newItem() { let item = Item(timestamp: .now, name: "\(Int.random(in: 0...3))") modelContext.insert(item) try! modelContext.save() } }

Thank you for your reply. I have submitted feedback regarding the Chinese characters. FB9639611 In my own code, I have used a similar scheme to yours, fuzzy querying Chinese Latin spelling results from CoreData data. extension String{     func transformToLatin(hasBlank: Bool = false) -> String {         let stringRef = NSMutableString(string: self) as CFMutableString         CFStringTransform(stringRef,nil, kCFStringTransformToLatin, false)         CFStringTransform(stringRef, nil, kCFStringTransformStripCombiningMarks, false)         let pinyin = stringRef as String         return hasBlank ? pinyin : pinyin.replacingOccurrences(of: " ", with: "")     } } I will try again as you suggested.

.onRecevier(books.publisher){ Changs in .... }