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$FocusState and Lists with rows containing TextFields
While I've seen examples of using $FocusState with Lists containing "raw" TextFields, in my use case, the List rows are more complex than that and contain multiiple elements, including TextFields. I obviously don't understand something fundamental here, because I am completely unable to get TextField-to-TextField tabbing to work. Can someone set me straight? Sample code demonstrating the issues: // // ContentView.swift // ListElementFocus // // Created by Richard Aurbach on 10/12/24. // import SwiftUI /// NOTE: in my actual app, the data model is actually a set of SwiftData /// PresistentModel objects. Here, I'm simulating them with an Observable. @Observable final class TestModel: Identifiable { public var id: UUID public var checked: Bool = false public var title: String = "Test" public var subtitle: String = "Subtitle" init(checked: Bool = false, title: String, subtitle: String) { self.id = UUID() self.checked = checked self.title = title self.subtitle = subtitle } } struct ContentView: View { /// Instead of a @Query... @State var records: [TestModel] = [ TestModel(title: "First title", subtitle: "blah, blah, blah"), TestModel(title: "Second title", subtitle: "more nonsense"), TestModel(title: "Third title", subtitle: "even more nonsense"), ] @FocusState var focus: UUID? var body: some View { Form { Section { HStack(alignment: .top) { Text("Goal:").font(.headline) Text( "If a user taps in the TextField in any row, they should be able to tab from row to row using any keyboard which supports a tab key." ) } HStack(alignment: .top) { Text("#1:").font(.headline) Text( "While I will admit that this code is probaby total garbage, I haven't been able to find any way to make tabbing from row to row to work at all." ) } HStack(alignment: .top) { Text("#2:").font(.headline) Text( "Tapping the checkbox button causes the row to flash with the current accent color, and I can't find any way to turn that off." ) } } header: { Text("Problems").font(.title3).bold() }.headerProminence(.increased) Section { List(records) { record in ListRow(record: record, focus: focus) .onKeyPress(.tab) { focus = next(record) return .handled } } } header: { Text("Example: Selector of Editable Items").font(.title3).bold() }.headerProminence(.increased) } .padding() } private func next(_ record: TestModel) -> UUID { guard !records.isEmpty else { return UUID() } if record.id == records.last!.id { return records.first!.id } if let index = records.firstIndex(where: { $0.id == record.id }) { return records[index + 1].id } return UUID() } } struct ListRow: View { @Bindable var record: TestModel var focus: UUID? @FocusState var focusState: Bool init(record: TestModel, focus: UUID?) { self.record = record self.focus = focus self.focusState = focus == record.id } var body: some View { HStack(alignment: .top) { Button { record.checked.toggle() } label: { record.checked ? Image(systemName: "checkmark.square.fill") : Image(systemName: "square") }.font(.title2).focusable(false) VStack(alignment: .leading) { TextField("title", text: $record.title).font(.headline) .focused($focusState) Text("subtitle").italic() } } } } #Preview { ContentView() }
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158
Oct ’24
Focus fails when TextField includes axis: .vertical
I've found another interesting issue with the Focus system. My text case is SwiftUI in Preview or Simulator (using an iPad mini case) -- I haven't tried this on other environments, so your mileage may vary. I have a Form including several TextFields. Adding the usual @FocusState logic, I observe that if I type a TAB key, then (a) If the TextFields are specified using TextField(“label”, text: $text), typing the tab key switches focus from field to field as expected, BUT (b) If the TextFields are specified using TextField(“label”, text: $text, axis: .vertical), typing the tab key adds whitespace to the field and does NOT change focus. In the latter case, I need to use an .onKeyPress(.tab) {….} modifier to achieve the desired result. Reported as FB15432840
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188
Oct ’24
Should I worry about this error message?
I have a SwiftData Model which includes a property of type Array. @Model final class Handler { public var id: UUID public var name: String public var mailingAddress: [String] . . . public init() { self.id = UUID() self.name = "" self.mailingAddress = [] . . . } When I use this Model in code, the mailingAddress field appears to work just as I would expect, but when saving it (running in Simulator), I see the following logged message: CoreData: fault: Could not materialize Objective-C class named "Array" from declared attribute value type "Array<String>" of attribute named mailingAddress Should I be worried about this?
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204
Oct ’24
TextFields inside a List lose focus after each character
My problem: I tap in one of the TextFields defined below and try to type. After typing a single character, the cursor disappears from the TextField and I need to tap in the field again to enter the next character. I have the following code: @Observable final class Species { . . . public var list: [String] . . . } struct SpeciesCapture: View { @State private var species = Species() @State var trainingList: [String] = [] var body: some View { NavigationStack { VStack(alignment: .leading) { HStack { Text("some text") Spacer() Button("Add") { trainingList.append("") } } List { ForEach($trainingList, id: \.self) { $animal in TextField("Animal", text: $animal) .textCase(.lowercase) } } } .onAppear { trainingList = species.list . . . } . . . // etc. } } } It appears that I am continually losing focus. How do I fix this problem? Xcode 16.0 targeting iOS 18. The behavior appears in both Preview and the Simulator. (Haven't tried it on a physical device).
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144
Sep ’24
Create AVPlayer instance from Data (rather than URL)?
In my SwiftUI/SwiftData application, I want to store videos in SwiftData objects (using external storage). To display them, I need to instantiate an AVPlayer (for use in a VideoPlayer view). But AVPlayer expects a URL, not a Data object. Obviously, I can solve this problem via a file-caching scheme (i.e., by creating a local file when needed, using an LRU cache to control it's lifetime), but this results in an extra copy of the data (besides the hidden local file managed by SwiftData/CoreData). However, since videos can be quite large, I would prefer not to do that. Has anyone any thoughts about how I can avoid the extra data copy?
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1.6k
Dec ’23
SwiftUI - Open a file via a fileURL
I am writing a SwiftUI-based app and have the following requirements: Use a file browser (such as UIDocumentPickerViewController) to find an arbitrary file (not one that the application knows how to open) which is external to the app bundle but local to the device the app is running on - either in local storage or on an iCloud drive. Save this location. At a later time, open this file. The file should open in an app that knows how to open it or in a browser. Do all of the above in a way that works with multiple devices (synced via CloudKit/SwiftData). For example, select a file on my iCloud drive on my Mac, then save it (using CloudKit/SwiftData) and open it on an iPad that has an app that can open it. I am addressing requirement #1 using UIDocumentPickerViewController wrapped with a UIViewControllerRepresentable. It returns a security-scoped URL. (Note: this worries me because of requirement #4). I use the Bookmark API to implement requirement #2. For requirement #3, I load the bookmark data, convert it back to a security-scoped URL and either Link("Open", destination: url) or @Environment(\.openURL) private var openURL if url.startAccessingSecurityScopedResource() { defer { url.stopAccessingSecurityScopedResource() } openURL(url) { accepted in // do something here } } Both of these implementations fail. The Link call responds with "invalid input parameters" (Error Domain=NSOSStatusErrorDomain, Code=-50), the openURL() call just returns false. So, my questions are: Since it appears the Link and openURL work for internet URLs, but not for security-scoped file URLs, how to I cause a document to be opened (using an application which knows how to open it or a browser). Since UIDocumentPickerViewController is returning a security-scoped URL, how can I make this work on a different device than the one on which the user selected the document? (Assuming, of course, that we are talking about a document that is on an iCloud drive that both devices have access to).
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2.4k
Oct ’23
List of relationship members fails to update when member content changes
FB13099793 I have a view which lists detail information about a SwiftData object, including a list of the members of its relationship. The Problem: If I use a modal presentation to edit the content of a relationship-member, upon return, the member has been updated, but the view falis to show it. The view updates correctly on adding a new member to the relationship, deleting a member, etc. But I cannot get the List to update if the content of the member changes (in a modal presentation). A few requirements that may be of significance: (1) The relationship (and inverse) are defined as optional because it is an eventual requirement for this app to use CloudKit synchronization. (2) The display of the members must be ordered. For this reason, the member object contains a "ordinal" property which is used to sort the the members. The relevant parts of the models are: @Model final public class Build { public var bld: Int @Relationship(inverse: \ChecklistItem.build) public var checklist: [ChecklistItem]? public init(bld: Int) { self.bld = bld self.checklist = [] } } @Model final public class ChecklistItem { public var ordinal: Int public var title: String public var subtitle: String // etc. public var build: Build? public init(build: Build) { self.ordinal = -1 self.title = "" self.subtitle = "" self.build = build } } The relevant parts of the view which handles the display is shown below. (Please look at the notes that follow the code for a discussion of some issues.) struct buildDetailChecklistView: View { @Environment(\.modelContext) var context: modelContext @State private var selectedItem: ChecklistItem? = nil @Bindable var build: Build init(build: Build) { self.build = Build } var body: some View { VStack { // ... some other stuff } List { ForEach((build.checklist ?? []) .sorted(by: { (a,b) in a.ordinal < b.ordinal})) { item in RowView(item) // displays title, subtitle, etc. .swipeActions(edge: .trailing, allowsFullSwipe: false) { Button { deleteRow(item) } label: { Label("Delete", systemImage: "trash") } .tint(.red) } .swipeActions(edge: .leading, allowsFullSwipe: false) { Button { selectedItem = item } label: { Label("Edit", systemImage: "pencil.line") } .tint(.blue) } } .sheet(item: $selectedItem) { item in BuildDetailAddEditChecklistItem(item: item, handler: updateChecklist(_:)) } } } private func updateChecklist(_ item: ChecklistItem) { if let index = build.checklist!.firstIndex(where: { $0 == item }) { DispatchQueue.main.async { [index] in build.checklist!.remove(at: index) try? context.save() build.checklist!.insert(item, at: index) } } } } Notes: (1) I cannot use a @Query macro in this case because of limitations in #Predicate. Every predicate I tried (to match the ChecklistItem's build member with it's parent's build object crash.) (2) I don't want to use @Query anyway because there is no need for the extra fetch operation it implies. All of the data is already present in the relationship. There ought to be a new macro/propertyWrapper to handle this. (3) Dealing with the required sort operation on the relationship members [in the ForEach call] is very awkward. There ought to be a better way. (4) The BuildDetailAddEditChecklistItem() function is a modal dialog, used to edit the content of the specified ChecklistItem (for example, changing its subtitle). On return, I expected to see the List display the new contents of the selected item. IT DOES NOT. (5) The handler argument of BuildDetailAddEditChecklist() is one of the things I tried to "get the List's attention". The handler function is called on a successful return from the model dialog. The implementation of the handler function finds the selected item in the checklist, removes it, and inserts it back into the checklist. I expected that this would force an update, but it does not.
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448
Sep ’23
SwiftData - What is Best Practice for returning an object from a sheet
SwiftUI & SwiftData. I have a view that lists SwiftData objects. Tapping on a list item navigates to a detail view. The list view also has a "New Object" button. Tapping it opens a sheet used to create a new object. There are, obviously, two possible outcomes from interacting with the sheet — a new object could be created or the user could cancel without creating a new object. If the user creates a new object using the sheet, I want to open the detail view for that object. My thought was to do this in the onDismiss handler for the sheet. However, that handler takes no arguments. What is best practice for handling this situation? In UIKit, I would return a Result<Object, Error> in a closure. That won't work here. What is the "correct" way to handle this that is compatible with SwiftData and the Observation framework?
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1.5k
Aug ’23
@Attribute 'unique' and complex keys
The 'unique' attribute is a really nice feature, BUT. In some of my apps, the unique identifier for an object is a combination of multiple attributes. (Example: a book title is not unique, but a combination of book title and author list is.) How do I model this with SwiftData? I cannot use @Attribute(.unique) on either the title OR the author list, but I want SwiftData to provide the same "insert or update" logic. Is this possible?
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Jun ’23
CoreData Migration for CloudKit
I am upgrading an existing (CoreData-based) iOS app to support CloudKit synchronization. This doesn't work because the app includes an ORDERED relationship. I need to perform a migration from this ordered relationship to something else that supports both CloudKit and maintains ordering. The problem is less about WHAT I need to do to support my requirements as it is HOW to perform the migration (so that my existing customers don't lose data.) Have you encountered this problem? How did you solve it?
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572
Mar ’23
WidgetKit — how to send data from Widget to main app
Back in the days of NCWidgetProviding, we had a button to open our app. We included code like the following in the app's info.plist: <key>CFBundleURLTypes</key> <array> <dict> <key>CFBundleTypeRole</key> <string>Editor</string> <key>CFBundleURLName</key> <string>com.xxxx.yyyy/string> <key>CFBundleURLSchemes</key> <array> <string>yyyy</string> </array> </dict> </array> and in the widget's button, we used code like: let appURL = URL(string: "yyyy://?url=\(zzz)") extensionContext?.open(appURL, completionHandler: nil) How can I achieve the same result using WidgetKit? (I.e., sending a URI to my main app)? The use case is that the widget displays a random record from a database and when the user taps on the widget, I want to open my app, displaying THAT SAME RECORD. Thanks.
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2.0k
Sep ’22
UICollectionView with DiffableDataSource
Xcode 13.1, iOS 25 SDK I have a UICollectionView (with a custom UICollectionViewLayout) which I am updating with a DiffableDataSource. This CollectionView displays a particular data object (with a given number of sections and items). The user can choose to display a different object (with a different number of sections and items), reusing this CollectionView. When this occurs, I do the following: (pass the new data object to the custom layout) let layout = collectionView.collectionViewLayout layout.invalidateLayout() collectionView.contentSize = layout.collectionViewContentSize (calculate a new snapshot and apply it) When the new data object has FEWER sections and/or items as the first, I get a series of warning messages (one for each of the cells that are no longer in the collection view) as follows: 2021-12-07 14:29:02.239301-0600 WineCorner[82916:1921357] [CollectionView] Layout attributes <UICollectionViewLayoutAttributes: 0x7f77b3047e00> index path: (<NSIndexPath: 0xa0f0b1eb018e754a> {length = 2, path = 0 - 4}); frame = (578.118 6; 160 160); transform = [0.70710678118654757, -0.70710678118654746, 0.70710678118654746, 0.70710678118654757, 0, 0]; zIndex = 1; were received from the layout <WineCorner.WineRackLayout: 0x7f77b1f1a0c0> but are not valid for the data source counts. Attributes will be ignored. Obviously, I am not handling the situation correctly. What should I do so that these warning messages are not issued?
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991
Dec ’21
Async/await and modal dialogs
In a UIKit context, has anyone had experience/success in using async/await to synchronize a modal dialog with other logic? I've tried it a bit without success. I.e, given a presented dialog, I want to capture data in the dialog, then use the results in a simple, linear fashion. (Something that looks like "Present the dialog, wait for results, use results" -- all inline without closures.) It seems to me that async/await with @MainActor ought to make that possible, but I haven't yet figured out how. I'd really like to see a real-world example.  Can you help?
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894
Sep ’21
Core Data: Fatal Error sorting using a computed property
I have a Core Data entity with a computed property and I want to sort the objects of this entity by this computed property. So • I build the NSFetchRequest in the normal way, including an NSSortDescriptor for sorting by this computed property. • Construct the usual NSFetchedResultController and call performFetch(). This results in a fatal error: *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'keypath score not found in entity Wine' I've tried to do this in several different ways, including (a) @objc public var score: Float { get { <getter code here> } } (b) Define score in the data model as transient, then @objc public var _score: Float { get { <getter code here> } } ... and ... public override func awakeFromFetch() { super.awakeFromFetch() score = _score } But the error persists. Is there any way to get this to work without abandoning NSFetchedResultsController, fetching unsorted records, sorting them programmatically and building the snapshot from the sorted array of objects? (I know, but it's the best I've been able to come up with so far...)
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2.3k
Aug ’21