I've been running into an issue using .fileImporter in SwiftUI already for a year. On iPhone simulator, Mac Catalyst and real iPad it works as expected, but when it comes to the test on a real iPhone, the picker just won't let you select files. It's not the permission issue, the sheet won't close at all and the callback isn't called. At the same time, if you use UIKits DocumentPickerViewController, everything starts working as expected, on Mac Catalyst/Simulator/iPad as well as on a real iPhone.
Steps to reproduce:
Create a new Xcode project using SwiftUI.
Paste following code:
import SwiftUI
struct ContentView: View {
@State var sShowing = false
@State var uShowing = false
@State var showAlert = false
@State var alertText = ""
var body: some View {
VStack {
VStack {
Button("Test SWIFTUI") {
sShowing = true
}
}
.fileImporter(isPresented: $sShowing, allowedContentTypes: [.item]) {result in
alertText = String(describing: result)
showAlert = true
}
VStack {
Button("Test UIKIT") {
uShowing = true
}
}
.sheet(isPresented: $uShowing) {
DocumentPicker(contentTypes: [.item]) {url in
alertText = String(describing: url)
showAlert = true
}
}
.padding(.top, 50)
}
.padding()
.alert(isPresented: $showAlert) {
Alert(title: Text("Result"), message: Text(alertText))
}
}
}
DocumentPicker.swift:
import SwiftUI
import UniformTypeIdentifiers
struct DocumentPicker: UIViewControllerRepresentable {
let contentTypes: [UTType]
let onPicked: (URL) -> Void
func makeCoordinator() -> Coordinator {
Coordinator(self)
}
func makeUIViewController(context: Context) -> UIDocumentPickerViewController {
let documentPicker = UIDocumentPickerViewController(forOpeningContentTypes: contentTypes, asCopy: true)
documentPicker.delegate = context.coordinator
documentPicker.modalPresentationStyle = .formSheet
return documentPicker
}
func updateUIViewController(_ uiViewController: UIDocumentPickerViewController, context: Context) {}
class Coordinator: NSObject, UIDocumentPickerDelegate {
var parent: DocumentPicker
init(_ parent: DocumentPicker) {
self.parent = parent
}
func documentPicker(_ controller: UIDocumentPickerViewController, didPickDocumentsAt urls: [URL]) {
print("Success!", urls)
guard let url = urls.first else { return }
parent.onPicked(url)
}
func documentPickerWasCancelled(_ controller: UIDocumentPickerViewController) {
print("Picker was cancelled")
}
}
}
Run the project on Mac Catalyst to confirm it working.
Try it out on a real iPhone.
For some reason, I can't attach a video, so I can only show a screenshot
Explore the various UI frameworks available for building app interfaces. Discuss the use cases for different frameworks, share best practices, and get help with specific framework-related questions.
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Hi, folks.
I know that in the new observation, class property changes can be automatically notified to SwiftUI, which is very convenient. But in the new observation framework, how to monitor the property changes of different model classes? For example, class1 has an instance of class2, and I need to notify class1 to perform some actions and make some changes when some properties of class2 are changed. How to do it in observation? In the past, I could use combined methods to write the second part of the code for monitoring. However, using the combined framework in observation is a bit confusing. I know this method can be withObservationTracking(_:onChange:) but it needs to be registered continuously.
If Observation is not possible, do I need to change my design structure?
Thanks.
// Observation
@Observable class Sample1 {
var count: Int = 0
var name = "Sample1"
}
@Observable class Sample2 {
var count: Int = 0
var name = "Sample2"
var sample1: Sample1?
init (sample1 : Sample1) {
self.sample1 = sample1
}
func render() {
withObservationTracking {
print("Accessing Sample1.count: \(sample1?.count ?? 0)")
} onChange: { [weak self] in
print("Sample1.count changed! Re-rendering Sample2.")
self?.handleSample1CountChange()
}
}
private func handleSample1CountChange() {
print("Handling count change in Sample2...")
self.count = sample1?.count ?? 0
}
}
// ObservableObject
class Sample1: ObservableObject {
@Published var count: Int = 0
var name = "Sample1"
}
class Sample2: ObservableObject {
@Published var count: Int = 0
var name = "Sample1"
var sample1: Sample1?
private var cancellables = Set<AnyCancellable>()
init (sample1 : Sample1) {
self.sample1 = sample1
setupSubscribers()
}
private func setupSubscribers() {
sample1?.$count
.receive(on: DispatchQueue.main)
.sink { [weak self] count in
guard let self = self else { return }
// Update key theory data
self.count = count
self.doSomeThing()
}
.store(in: &cancellables)
}
private func doSomeThing() {
print("Count changes, need do some thing")
}
}
I am using LazyVStack inside a ScrollView. I understand that lazy views are rendered only when they come into view. However, I haven’t heard much about memory deallocation.
I observed that in iOS 18 and later, when scrolling up, the bottom-most views are deallocated from memory, whereas in iOS 17, they are not (Example 1).
Additionally, I noticed a similar behavior when switching views using a switch. When switching views by pressing a button, the view was intermittently deinitialized. (Example 2).
Example 1)
struct ContentView: View {
var body: some View {
ScrollView {
LazyVStack {
ForEach(0..<40) { index in
CellView(index: index)
}
}
}
.padding()
}
}
struct CellView: View {
let index: Int
@StateObject var viewModel = CellViewModel()
var body: some View {
Rectangle()
.fill(Color.accentColor)
.frame(width: 300, height: 300)
.overlay {
Text("\(index)")
}
.onAppear {
viewModel.index = index
}
}
}
class CellViewModel: ObservableObject {
@Published var index = 0
init() {
print("init")
}
deinit {
print("\(index) deinit")
}
}
#Preview {
ContentView()
}
Example 2
struct ContentView: View {
@State var index = 0
var body: some View {
LazyVStack {
Button(action: {
if index > 5 {
index = 0
} else {
index += 1
}
}) {
Text("plus index")
}
MidCellView(index: index)
}
.padding()
}
}
struct MidCellView: View {
let index: Int
var body: some View {
switch index {
case 1:
CellView(index: 1)
case 2:
CellView(index: 2)
case 3:
CellView(index: 3)
case 4:
CellView(index: 4)
default:
CellView(index: 0)
}
}
}
struct CellView: View {
let index: Int
@StateObject var viewModel = CellViewModel()
var body: some View {
Rectangle()
.fill(Color.accentColor)
.frame(width: 300, height: 300)
.overlay {
Text("\(index)")
}
.onAppear {
viewModel.index = index
}
}
}
class CellViewModel: ObservableObject {
@Published var index = 0
init() {
print("init")
}
deinit {
print("\(index) deinit")
}
}
--------------------
init
init
init
init
init
2 deinit
3 deinit
4 deinit
init
When you touch down on a button in a scroll view, you can cancel the tap by scrolling. In SwiftUI, this works correctly when the scroll view is not inside a dismissible sheet.
However, if the scroll view is inside a sheet that can be dismissed with a drag gesture, scrolling does not cancel the button touch, and after scrolling, the button tap is activated.
This happens whether the modal is presented from SwiftUI using the sheet modifier, or wrapped in a UIHostingController and presented from UIKit.
This is a huge usability issue for modals with scrollable content that have buttons inside of them.
Video of behavior: https://youtube.com/shorts/w6eqsmTrYiU
Easily reproducible with this code:
import SwiftUI
struct ContentView: View {
@State private var isPresentingSheet = false
var body: some View {
ScrollView {
LazyVStack {
ForEach(0..<100, id: \.self) { index in
Button {
isPresentingSheet = true
} label: {
Text("Button \(index)")
.padding(.horizontal)
.padding(.vertical, 5)
.frame(maxWidth: .infinity, alignment: .leading)
}
}
}
.padding()
}
.sheet(isPresented: $isPresentingSheet) {
ContentView()
}
}
}
I noticed if I show a sheet from a List row, then remove the row the sheet isn't removed from the screen like it is if using VStack or LazyVStack.
I'd be interested to know the reason why the sheet isn't removed from the screen in the code below. It only occurs with List/Form. VStack/LazyVStack gives the expected result. I was wondering if it is an implementation issue, e.g. since List is backed by UICollectionView maybe the cells can't be the presenter of the sheet for some reason.
Launch on iPhone 16 Pro Simulator iOS 18.2
Tap "Show Button"
Tap "Show Sheet"
What is expected:
The sheet should disappear after 5 seconds. And I don't mean it should dismiss, I just mean removed from the screen. Similarly if the View that showed the sheet was re-added and its show @State was still true, then the sheet would be added back to the screen instantly without presentation animation.
What actually happens:
Sheet remains on screen despite the row that presented the sheet being removed.
Xcode 16.2
iOS Simulator 18.2.
struct ContentView: View {
@State var showButton = false
var body: some View {
Button("\(showButton ? "Hide" : "Show" ) Button") {
showButton = true
Task {
try? await Task.sleep(for: .seconds(5))
self.showButton = false
}
}
//LazyVStack { // does not have this problem
List {
if showButton {
SheetButton()
}
}
}
}
struct SheetButton: View {
@State var sheet = false
@State var counter = 0
var body: some View {
Text(counter, format: .number)
Button("\(sheet ? "Hide" : "Show") Sheet") {
counter += 1
sheet.toggle()
}
.sheet(isPresented: $sheet) {
Text("Wait... This should auto-hide in 5 secs. Does not with List but does with LazyVStack.")
Button("Hide") {
sheet = false
}
.presentationDetents([.fraction(0.3)])
}
// .onDisappear { sheet = false } // workaround
}
}
I can work around the problem with .onDisappear { sheet = false } but I would prefer the behaviour to be consistent across the container controls.
Hi,
I have noticed a major change to a SwiftUI API behavior in iOS18.4beta1 which breaks my app's functionality, and I've started hearing from users running the new beta that the app doesn't correctly work for them anymore.
The problem is with views that contain a List with multiple-selection, and the contextMenu API applied with the ‘primaryAction’ callback that is triggered when the user taps on a row. Previously, if the user tapped on a row, this callback was triggered with the 'selectedItems' showing the tapped item. With iOS18.4beta, the same callback is triggered with ‘selectedItems’ being empty.
I have the code to demonstrate the problem:
struct ListSelectionTestView: View {
@State private var items: [TimedItem] = [
TimedItem(number: 1, timestamp: "2024-11-20 10:00"),
TimedItem(number: 2, timestamp: "2024-11-20 11:00"),
TimedItem(number: 3, timestamp: "2024-11-20 12:00")
]
@State var selectedItems = Set<TimedItem.ID>()
var body: some View {
NavigationStack {
List(selection: $selectedItems) {
ForEach(items) { item in
Text("Item \(item.number) - \(item.timestamp)")
}
}
.contextMenu(forSelectionType: TimedItem.ID.self, menu: {_ in
Button(action: {
print("button called - count = \(selectedItems.count)")
}) {
Label("Add Item", systemImage: "square.and.pencil")
}
}, primaryAction: {_ in
print("primaryAction called - count = \(selectedItems.count)")
})
}
}
}
struct TimedItem: Identifiable {
let id = UUID()
let number: Int
let timestamp: String
}
#Preview {
ListSelectionTestView()
}
Running the same code on iOS18.2, and tapping on a row will print this to the console:
primaryAction called - count = 1
Running the same code on iOS18.4 beta1, and tapping on a row will print this to the console:
primaryAction called - count = 0
So users who were previously selecting an item from the row, and then seeing expected behavior with the selected item, will now suddenly tap on a row and see nothing. My app's functionality relies on the user selecting an item from a list to see another detailed view with the selected item's contents, and it doesn't work anymore.
This is a major regression issue. Please confirm and let me know. I have filed a feedback: FB16593120
To add a background to the tab content I implement the following background, nesting another modifier equal within this one.
.background(
.background // ERROR: Ambiguous use of 'background'
.shadow(.drop(
color: .primary.opacity(0.08),
radius: 5, x: 5, y: 5)
)
.shadow(.drop(
color: .primary.opacity(0.08),
radius: 5, x: -5, y: -5)
),
in: .capsule
)
Hi,
I am trying to use a flag image inside a picker like this:
Picker("Title: ", selection: $selection){
ForEach(datas, id: \.self){ data in
HStack{
Text(data.name)
if condition {
Image(systemName: "globe")
}else {
Image(img)
}
}
.tag(data.name)
.padding()
}
}
All images are loading successfully but only system images are resized correctly.
Images loaded from Assets are appearing in their default size.
I have tried to size the images with frames, etc but with no luck.
Any idea, help will be much appreciated.
Thanks in advance!
I wanted to perform simulation in my application as a self tour guide for my user. For this I want to programatically simulate various user interaction events like button click, keypress event in the UITextField or moving the cursor around in the textField. These are only few examples to state, it can be any user interaction event or other events.
I wanted to know what is the apple recommendation on how should these simulations be performed? Is there something that apple offers like creating an event which can be directly executed for simulations. Is there some library available for this purpose?
Just learning Swift and SwiftUI, having fun in Xcode. I have the following custom view defined, but when I try to test it, the information doesn't get updated as I expect. When I use the button defined INSIDE the custom view, the update works as expected. When I use the button defined in the Preview body, it doesn't. The "lines" variable of the custom view appears not to be updated in that case.
I know I'm missing something fundamental here about either view state binding or the preview environment, but I'm stumped. Any ideas?
import SwiftUI
struct ConsoleView: View {
var maxLines : Int = 26
private enum someIDs { case textID}
@State private var numLines : Int = 0
@State var lines = "a\nb\nc\n"
var body: some View {
VStack(alignment: .leading, spacing:0 ) {
ScrollViewReader { proxy in
ScrollView {
Button("Scroll to Bottom") {
withAnimation {
proxy.scrollTo(someIDs.textID, anchor: .bottom)
}
}
Text(lines)
.id(someIDs.textID)
.multilineTextAlignment(.leading)
.frame(maxWidth: .infinity, alignment: .bottomLeading)
.padding()
.onChange ( of: lines) {
withAnimation {
proxy.scrollTo( someIDs.textID, anchor: .bottom)
}
}
}
Button("Add more") {
writeln("More")
//writeln(response)
}
}
}
}
private func clipIfNeeded () {
if (numLines>=maxLines) {
if let i = lines.firstIndex(of: "\n") {
lines = String(lines.suffix( from: lines.index(after:i)))
}
}
}
func writeln ( _ newText : String) {
print("adding '\(newText)' to lines")
//clipIfNeeded()
write( newText )
write("\n")
numLines += 1
print(lines)
}
func write ( _ newText : String) {
lines += newText
}
}
#Preview {
VStack() {
var myConsole = ConsoleView(lines: "x\ny\nz\n")
myConsole
Button("Add stuff") {
myConsole.writeln("Stuff")
}
}
}
Hi everyone,
I've been testing the requestGeometryUpdate() API in iOS, and I noticed something unexpected: it allows orientation changes even when the device’s orientation lock is enabled.
Test Setup:
Use requestGeometryUpdate() in a SwiftUI sample app to toggle between portrait and landscape (code below).
Manually enable orientation lock in Control Center.
Press a button to request an orientation change in sample app.
Result: The orientation changes even when orientation lock is ON, which seems to override the expected system behavior.
Questions:
Is this intended behavior?
Is there official documentation confirming whether this is expected? I haven’t found anything in Apple’s Human Interface Guidelines (HIG) or UIKit documentation that explicitly states this.
Since this behavior affects a system-wide user setting, could using requestGeometryUpdate() in this way lead to App Store rejection?
Since Apple has historically enforced respecting user settings, I want to clarify whether this approach is compliant.
Would love any official guidance or insights from Apple engineers.
Thanks!
struct ContentView: View {
@State private var isLandscape = false // Track current orientation state
var body: some View {
VStack {
Text("Orientation Test")
.font(.title)
.padding()
Button(action: toggleOrientation) {
Text(isLandscape ? "Switch to Portrait" : "Switch to Landscape")
.bold()
.padding()
.background(Color.blue)
.foregroundColor(.white)
.cornerRadius(10)
}
}
}
private func toggleOrientation() {
guard let scene = UIApplication.shared.connectedScenes.first as? UIWindowScene else {
print("No valid window scene found")
return
}
// Toggle between portrait and landscape
let newOrientation: UIInterfaceOrientationMask = isLandscape ? .portrait : .landscapeRight
let geometryPreferences = UIWindowScene.GeometryPreferences.iOS(interfaceOrientations: newOrientation)
scene.requestGeometryUpdate(geometryPreferences) { error in
print("Failed to change orientation: \(error.localizedDescription)")
}
self.isLandscape.toggle()
}
}
We use @Query macro in our App. After we got macOS 15.3 update, our App crashes at @Query line.
SwiftData/Schema.swift:305: Fatal error: KeyPath \Item.<computed 0x0000000100599e54 (Vec3D)>.x points to a field (<computed 0x0000000100599e54 (Vec3D)>) that is unknown to Item and cannot be used.
This problem occurs only when the build configuration is "Release", and only when I use @Query macro with sort: parameter. The App still works fine on macOS 14.7.3.
This issue seems similar to what has already been reported in the forum. It looks like a regression on iOS 18.3.
https://developer.apple.com/forums/thread/773308
Item.swift
import Foundation
import SwiftData
public struct Vec3D {
let x,y,z: Int
}
extension Vec3D: Codable { }
@Model
final class Item {
var timestamp: Date
var vec: Vec3D
init(timestamp: Date) {
self.timestamp = timestamp
self.vec = Vec3D(x: 0, y: 0, z: 0)
}
}
ContentView.Swift
import SwiftUI
import SwiftData
struct ContentView: View {
@Environment(\.modelContext)
private var modelContext
@Query(sort: \Item.vec.x) // Crash
private var items: [Item]
var body: some View {
NavigationSplitView {
List {
ForEach(items) { item in
NavigationLink {
Text("Item at \(item.timestamp, format: Date.FormatStyle(date: .numeric, time: .standard))")
} label: {
Text(item.timestamp, format: Date.FormatStyle(date: .numeric, time: .standard))
}
}
.onDelete(perform: deleteItems)
}
.navigationSplitViewColumnWidth(min: 180, ideal: 200)
.toolbar {
ToolbarItem {
Button(action: addItem) {
Label("Add Item", systemImage: "plus")
}
}
}
} detail: {
Text("Select an item")
}
}
private func addItem() {
withAnimation {
let newItem = Item(timestamp: Date())
modelContext.insert(newItem)
}
}
private func deleteItems(offsets: IndexSet) {
withAnimation {
for index in offsets {
modelContext.delete(items[index])
}
}
}
}
when I input something in UITextField or UITextView, I got the error below:*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[NSXPCEncoder _checkObject:]: This coder only encodes objects that adopt NSSecureCoding (object is of class 'NSMallocBlock').'
This pertains to iPad apps and UITabbarController in UIKit.
Our internal app for employees utilizes UITabbarController displayed at the bottom of the screen. Users prefer to maintain consistency with it being at the bottom. It becomes challenging to argue against this when users point out the iPhone version displaying it "correctly" at the bottom. My response is to trust Apple's design team to keep it at the top.
One workaround is to develop the app using the previous Xcode version, version 15 (via Xcode Cloud), targeting padOS17. This ensures the tab bar is shown at the bottom of the screen. However, this approach has its drawbacks: Apple may not support it in the future, leading to missed secure updates for the app, among other issues.
Exploring the UITabbarController mode appears to be the solution I am seeking. To quote the documentation "on iPad, If the tabs array contains one or more UITabGroup items, the system displays the content as either a tab bar or a sidebar, depending on the context. Otherwise, it only displays the content only as a tab bar.". The part "displays the content only as a tab bar." made think this is BAU:
class ViewController: UITabBarController {
override func viewDidLoad() {
super.viewDidLoad()
self.mode = .tabBar
}
}
Unfortunately, this does not resolve the issue.
Is there an API method that can force the tabbar to its previous bottom position?
The app uses multiple windows. When we split a window to launch another instance, the tab bar appears at the bottom. This behavior seems tied to the form factor—or potentially to how many items are in the tab bar.
We could build a custom tab bar to override this, but that goes against my “don’t reinvent the wheel” principle.
Any comments we welcome and thank you for reading this (to the end)
Theo
Hi folks,
Unsure if I've implemented some sort of anti-pattern here, but any help or feedback would be great.
I've created a minimal reproducible sample below that lets you filter a list of people and mark individuals as a favourite.
When invoking the search function on a physical device running iOS 18.3.1, it crashes with Swift/ContiguousArrayBuffer.swift:675: Fatal error: Index out of range.
It runs fine on iOS 17 (physical device) and also on the various simulators I've tried (iOS 18.0, iOS 18.2, iOS 18.3.1).
If I remove the toggle binding, the crash doesn't occur (but I also can't update the toggles in the view model).
I'm expecting to be able to filter the list without a crash occurring and retain the ability to have the toggle switches update the view model.
Sample code is below. Thanks for your time 🙏!
import SwiftUI
struct Person {
let name: String
var isFavorite = false
}
@MainActor
class ViewModel: ObservableObject {
private let originalPeople: [Person] = [
.init(name: "Holly"),
.init(name: "Josh"),
.init(name: "Rhonda"),
.init(name: "Ted")
]
@Published var filteredPeople: [Person] = []
@Published var searchText: String = "" {
didSet {
if searchText.isEmpty {
filteredPeople = originalPeople
} else {
filteredPeople = originalPeople.filter { $0.name.lowercased().contains(searchText.lowercased()) }
}
}
}
init() {
self.filteredPeople = originalPeople
}
}
struct ContentView: View {
@ObservedObject var viewModel = ViewModel()
var body: some View {
NavigationStack {
List {
ForEach($viewModel.filteredPeople, id: \.name) { person in
VStack(alignment: .leading) {
Text(person.wrappedValue.name)
Toggle("Favorite", isOn: person.isFavorite)
}
}
}
.navigationTitle("Contacts")
}
.searchable(text: $viewModel.searchText)
}
}
#Preview {
ContentView()
}```
I'm implementing infinite scrolling with Swift Charts where additional historical data loads when scrolling near the beginning of the dataset. However, when new data is loaded, the chart's scroll position jumps unexpectedly.
Current behavior:
Initially loads 10 data points, displaying the latest 5
When scrolling backwards with only 3 points remaining off-screen, triggers loading of 10 more historical points
After loading, the scroll position jumps to the 3rd position of the new dataset instead of maintaining the current view
Expected behavior:
Scroll position should remain stable when new data is loaded
User's current view should not change during data loading
Here's my implementation logic using some mock data:
import SwiftUI
import Charts
struct DataPoint: Identifiable {
let id = UUID()
let date: Date
let value: Double
}
class ChartViewModel: ObservableObject {
@Published var dataPoints: [DataPoint] = []
private var isLoading = false
init() {
loadMoreData()
}
func loadMoreData() {
guard !isLoading else { return }
isLoading = true
let newData = self.generateDataPoints(
endDate: self.dataPoints.first?.date ?? Date(),
count: 10
)
self.dataPoints.insert(contentsOf: newData, at: 0)
self.isLoading = false
print("\(dataPoints.count) data points.")
}
private func generateDataPoints(endDate: Date, count: Int) -> [DataPoint] {
var points: [DataPoint] = []
let calendar = Calendar.current
for i in 0..<count {
let date = calendar.date(
byAdding: .day,
value: -i,
to: endDate
) ?? endDate
let value = Double.random(in: 0...100)
points.append(DataPoint(date: date, value: value))
}
return points.sorted { $0.date < $1.date }
}
}
struct ScrollableChart: View {
@StateObject private var viewModel = ChartViewModel()
@State private var scrollPosition: Date
@State private var scrollDebounceTask: Task<Void, Never>?
init() {
self.scrollPosition = .now.addingTimeInterval(-4*24*3600)
}
var body: some View {
Chart(viewModel.dataPoints) { point in
BarMark(
x: .value("Time", point.date, unit: .day),
y: .value("Value", point.value)
)
}
.chartScrollableAxes(.horizontal)
.chartXVisibleDomain(length: 5 * 24 * 3600)
.chartScrollPosition(x: $scrollPosition)
.chartXScale(domain: .automatic(includesZero: false))
.frame(height: 300)
.onChange(of: scrollPosition) { oldPosition, newPosition in
scrollDebounceTask?.cancel()
scrollDebounceTask = Task {
try? await Task.sleep(for: .milliseconds(300))
if !Task.isCancelled {
checkAndLoadMoreData(currentPosition: newPosition)
}
}
}
}
private func checkAndLoadMoreData(currentPosition: Date?) {
guard let currentPosition,
let earliestDataPoint = viewModel.dataPoints.first?.date else {
return
}
let timeInterval = currentPosition.timeIntervalSince(earliestDataPoint)
if timeInterval <= 3 * 24 * 3600 {
viewModel.loadMoreData()
}
}
}
I attempted to compensate for this jump by adding:
scrollPosition = scrollPosition.addingTimeInterval(10 * 24 * 3600)
after viewModel.loadMoreData(). However, this caused the chart to jump in the opposite direction by 10 days, rather than maintaining the current position.
What's the problem with my code and how to fix it?
Running the Apple sample code “Sharing Core Data objects between iCloud users” has presented the following challenge:
After the creation of a CKRecord in a Persistent CloudKit Container private database, the owner then shares it to a participant. All works fine.
Then the Owner wants to stop sharing. That's fine too, although the CKRecord remains within the same shared zone within the owner's private database; it doesn't move back to the private database.
Then the owner wants to delete the CKRecord completely. Deletion of the record works, but evidence of the CKShare within the shared zone still remains inside the owner's private database.
It is clearly visible on the CloudKit dashboard.
Probably doesn’t take up much memory but v messy and not cool.
How to delete this CKShare completely, leaving no trace?
Any ideas would be most gratefully received!
Recently I've made 1 character mistake in my code and have hard time during searching what was the problem.
Basically I forgot to set dot near one of the frame modifiers and compiler did not warn me, but during app running I got 100% CPU and rocket increase of RAM (on real app). Feels like recursion, but no any hint in call stack inside Xcode on crash stop.
struct BadView: View {
var body: some View {
Color.red
frame(height: 36)
}
}
I would like to see at least warning for such cases. Problem may look simple on this small example, but if you added 1k+ lines after last compilation - searching this type of errors could be problematic when you have no idea what to search.
I've encountered an issue where storing a throws(PermissionError) closure as a property inside a SwiftUI View causes a runtime crash on iOS 17, while it works correctly on iOS 18.
Here’s an example of the affected code:
enum PermissionError: Error {
case denied
}
struct PermissionCheckedView<AllowedContent: View, DeniedContent: View>: View {
var protectedView: () throws(PermissionError) -> AllowedContent
var deniedView: (PermissionError) -> DeniedContent
init(
@ViewBuilder protectedView: @escaping () throws(PermissionError) -> AllowedContent,
@ViewBuilder deniedView: @escaping (PermissionError) -> DeniedContent
) {
self.protectedView = protectedView
self.deniedView = deniedView
}
public var body: some View {
switch Result(catching: protectedView) {
case .success(let content): content
case .failure(let error): deniedView(error)
}
}
}
@main
struct TestApp: App {
var body: some Scene {
WindowGroup {
PermissionCheckedView {
} deniedView: { _ in
}
}
}
}
Specifically this is the stack trace (sorry for the picture I didn't know how to get the txt):
If I use var protectedView: () throws -> AllowedContent without typed throws it works.
Hi! While working on my Swift Student Challenge submission it seems that I found a race condition (TOCTOU) bug in SwiftUI when using sheets, and I'm not sure if this is expected behaviour or not.
Here's an example code:
import SwiftUI
struct ContentView: View {
@State var myVar: Int?
@State private var presentSheet: Bool = false
var body: some View {
VStack {
// Uncommenting the following Text() view will "fix" the bug (kind of, see a better workaround below).
// Text("The value is \(myVar == nil ? "nil" : "not nil")")
Button {
myVar = nil
} label: {
Text("Set value to nil.")
}
Button {
myVar = 1
presentSheet.toggle()
} label: {
Text("Set value to 1 and open sheet.")
}
}
.sheet(isPresented: $presentSheet, content: {
if myVar == nil {
Text("The value is nil")
.onAppear {
print(myVar) // prints Optional(1)
}
} else {
Text("The value is not nil")
}
})
}
}
When opening the app and pressing the open sheet button, the sheet shows "The value is nil", even though the button sets myVar to 1 before the presentSheet Bool is toggled.
Thankfully, as a workaround to this bug, I found out you can change the sheet's view to this:
.sheet(isPresented: $presentSheet, content: {
if myVar == nil {
Text("The value is nil")
.onAppear {
if myVar != nil {
print("Resetting View (TOCTOU found)")
let mySwap = myVar
myVar = nil
myVar = mySwap
}
}
} else {
Text("The value is not nil")
}
})
This triggers a view refresh by setting the variable to nil and then to its non-nil value again if the TOCTOU is found.
Do you think this is expected behaivor? Should I report a bug for this? This bug also affects .fullScreenCover() and .popover().