In UIKit, certain events like a button tap can be simulated using:
button.sendActions(for: .touchUpInside)
This allows us to trigger the button’s action programmatically.
However, in SwiftUI, there is no direct equivalent of sendActions(for:) for views like Button. What is the recommended approach to programmatically simulate a SwiftUI button tap and trigger its action?
Is there an alternative mechanism to achieve this(and for other events under UIControl.event) , especially in scenarios where we want to test interactions or trigger actions without direct user input?
UIKit
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I set the titleView of a view controller to a UISlider like so in viewDidLoad:
UISlider *slider = [UISlider new];
self.navigationItem.titleView = slider;
The desired outcome is that the slider takes the full width of the title view. This is working fine when the view is loaded in the wider landscape mode. The slider adjust its size as expected when rotating to portrait mode.
However, when the view is loaded in the narrower portrait mode and then the device is rotated to landscape, the slider does not grow in width to make use of the newly available size.
Why is that so and how can it get the desired outcome as described?
After viewDidLoad:
After rotating:
I’ve tried implementing the accessibilityPerformMagicTap() method in a specific UIViewController, its view, and even in AppDelegate, but I am not receiving any callbacks.
I directly overrode this method in the mentioned areas, but it never gets triggered when performing a magic tap.
How can I properly observe and handle the accessibilityPerformMagicTap() action?
Hello. Recently, our app has been experiencing crashes with the message 'Attempting to attach window to an invalidated scene' when creating a UIWindow.
Our code stores the UIWindowScene provided in the scene(:willConnectTo:options:) function in a global variable and does not change the set scene until the scene(:willConnectTo:options:) function is called again. Additionally, we do not perform any actions related to the disconnect event.
func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {
guard let windowScene = (scene as? UIWindowScene) else { return }
hudManager.setup(windowScene: windowScene)
// ...
}
func sceneDidDisconnect(_ scene: UIScene) {
// do nothing
}
In all crash logs, the activationState of the WindowScene is "unattached", so I initially thought that creating a UIWindow with a scene in the 'unattached' state should be avoided.
However, in the scene(_:willConnectTo:options:) function, the scene's state is also 'unattached', yet the UIWindow is created successfully here, which makes me think that deciding whether to create a window based on the activationState is incorrect.
I did find that trying to create a UIWindow with a scene after it has been disconnected causes a crash.
func sceneDidDisconnect(_ scene: UIScene) {
// Crash occur here and scene's state is `unattached`
let window = UIWindow(windowScene: scene as! UIWindowScene)
}
If the activationState alone cannot be used to determine the validity of a scene, is there another way to check the validity of a Scene? Thank you
Hello everyone,
I've run into a peculiar behavior with UINavigationController's setViewControllers on iOS 18.2 (I guess it might be reproducible on older versions) when reordering view controllers, and I wonder if anyone can shed some light on this issue.
Initial State: The navigation stack is [A - B - C].
Without Animation: Setting [A - C - B] updates the stack to: A - C - B as expected.
With Animation: Using the same command with animation changes the stack to [A - B], oddly omitting C.
Has anyone else noticed similar behavior or knows why animations might disrupt the stack's update this way? I'd appreciate any insights or suggestions.
Thanks, Dmytro
I have a struct that holds an instance of UINavigationController:
struct NavigationController {
static let shared = UINavigationController()
}
I use NavigationController.shared to push and pop ViewControllers around the app, rather than using the ViewController's .navigationController property.
The issue I'm having is that when I pop I get new instances of my previous ViewController, this is my hierarchy:
(0) UIWindow
|
---- (1) NavigationController (is set as the UIWindow.rootViewController)
|
---- (2) UITabBarController (is set with NavigationController.shared.setViewControllers)
|
---- (3) ViewController (HomeVC) (is the first tab of the UITabController)
|
---- (4) ViewController (ScanVC) (is pushed into the stack by NavigationController.shared.pushViewController)
---- (5) ViewController (NotificationsVC)
---- (6) ViewController (SettingsVC)
I put a print statement in my HomeVC in the viewDidLoad method
My understanding is that the viewDidLoad should only be called once in the lifecycle of a ViewController
When I go back to the HomeVC from the ScanVC then the print always gets triggered which means I have a new instance of the HomeVC
This is the print statement I created inside the viewDidLoad method:
print("\(#function) View Did Load, instance: \(self)")
Here's the output from going back and forth from the HomeVC to ScanVC:
viewDidLoad() View Did Load, instance: <HomeVC: 0x118db0000>
viewDidLoad() View Did Load, instance: <HomeVC: 0x118db3100>
viewDidLoad() View Did Load, instance: <HomeVC: 0x118db0700>
Any one has any suggestions on how to fix this? Because ideally going back to the HomeVC should not instantiate a new ViewController.
I tested this on a small test project and viewDidLoad would only be triggered once when the ViewController was instantiated.
I'm building an app using UITabbarController with 2 tabs: screen A and B. When standing on tab B and I taps on tab A, the order in which the events are triggered will be:
For iOS < 18:
viewWillDisappear() of screen B
tabBarController(_:didSelect:) of UITabbarController
For iOS >= 18:
tabBarController(_:didSelect:) of UITabbarController
viewWillDisappear() of screen B
So my question is this an issue or a new update from Apple on iOS 18.*?
I’m currently exploring VoiceOver accessibility in iOS and looking for the best way to reduce the number of swipes required to navigate a UITableView. I’ve come across a couple of potential solutions but am unsure which is preferred.
Solution 1: Grouping Subviews in Each Cell
Combine all subviews inside a UITableViewCell into a single accessibility element.
Provide a concise and meaningful accessibilityLabel.
Use custom actions (UIAccessibilityCustomAction) or accessibilityActivationPoint to handle interactions on specific elements within the cell.
Solution 2: Using UIAccessibilityContainerDataTableCell & UIAccessibilityContainerDataTable
Implement UIAccessibilityContainerDataTable for structured table navigation.
Make each cell conform to UIAccessibilityContainerDataTableCell, defining its row and column positions.
However, I’m finding this approach a bit complex, and I need guidance on properly implementing these protocols.
Additionally, in my case, VoiceOver is not navigating to Section 2—I’m not sure why.
Questions:
Which of these approaches is generally preferred for better VoiceOver navigation?
How do I properly implement UIAccessibilityContainerDataTable so that all sections and rows are navigable?
Any best practices or alternative recommendations?
Would really appreciate any insights or guidance!
At this line of code (SketchTextSelectionManager.swift:449), sometimes there will be crashes based on crashlytics reports.
let selection = pdfPage.selectionForWord(at: location)
This is directly calling into PDFKit's PDFPage#selection method: https://developer.apple.com/documentation/pdfkit/pdfpage/selectionforword(at:)
Attached the full stacktrace:
Crashed: com.apple.root.user-initiated-qos.cooperative
0 CoreGraphics 0x30c968 PageLayout::getWordRange(unsigned long, long) const + 908
1 CoreGraphics 0x30bbc0 PageLayout::getTextRangeIndex(CGPoint, CGPDFSelectionType, SelectionPrecision) const + 2292
2 CoreGraphics 0x44a53c CGPDFSelectionCreateBetweenPointsWithOptions + 384
3 PDFKit 0x8d5f8 -[PDFPage selectionFromPoint:toPoint:type:] + 168
4 PDFKit 0x92040 -[PDFPage _rvItemAtPoint:] + 64
5 PDFKit 0x91f4c -[PDFPage rvItemAtPoint:] + 84
6 PDFKit 0x8caa8 -[PDFPage selectionForWordAtPoint:] + 40
7 MyApp 0x8420e0 closure #1 in SketchTextSelectionManager.startNewTextSelection(pageId:location:) + 449 (SketchTextSelectionManager.swift:449)
8 MyApp 0x841a70 SketchTextSelectionManager.startNewTextSelection(pageId:location:) + 205 (CurrentNoteManager.swift:205)
9 libswift_Concurrency.dylib 0x61104 swift::runJobInEstablishedExecutorContext(swift::Job*) + 252
10 libswift_Concurrency.dylib 0x63a28 (anonymous namespace)::ProcessOutOfLineJob::process(swift::Job*) + 480
11 libswift_Concurrency.dylib 0x611c4 swift::runJobInEstablishedExecutorContext(swift::Job*) + 444
12 libswift_Concurrency.dylib 0x62514 swift_job_runImpl(swift::Job*, swift::SerialExecutorRef) + 144
13 libdispatch.dylib 0x15d8c _dispatch_root_queue_drain + 392
14 libdispatch.dylib 0x16590 _dispatch_worker_thread2 + 156
15 libsystem_pthread.dylib 0x4c40 _pthread_wqthread + 228
16 libsystem_pthread.dylib 0x1488 start_wqthread + 8
```
At this line of code (SketchTextSelectionManager.swift:378), sometimes there will be crashes based on crashlytics reports. In the reports, it seems like this only happens for RTL text range.
let selection = pdfPage.selection(
from: CGPoint(x: fromStart.x + 1, y: fromStart.y - 1),
to: CGPoint(x: toEnd.x - 1, y: toEnd.y + 1)
)
This is directly calling into PDFKit's PDFPage#selection method: https://developer.apple.com/documentation/pdfkit/pdfpage/selection(from:to:)
Attached the full stacktrace:
Crashed: com.apple.root.user-initiated-qos.cooperative
0 CoreGraphics 0x30598c PageLayout::convertRTLTextRangeIndexToStringRangeIndex(long) const + 156
1 CoreGraphics 0x44c3f0 CGPDFSelectionCreateBetweenPointsWithOptions + 224
2 PDFKit 0x91d00 -[PDFPage selectionFromPoint:toPoint:type:] + 168
3 MyApp 0x841044 closure #1 in SketchTextSelectionManager.handleUserTouchMoved(_:) + 378 (SketchTextSelectionManager.swift:378)
4 MyApp 0x840cb0 SketchTextSelectionManager.handleUserTouchMoved(_:) + 205 (CurrentNoteManager.swift:205)
5 libswift_Concurrency.dylib 0x60f5c swift::runJobInEstablishedExecutorContext(swift::Job*) + 252
6 libswift_Concurrency.dylib 0x63a28 (anonymous namespace)::ProcessOutOfLineJob::process(swift::Job*) + 480
7 libswift_Concurrency.dylib 0x6101c swift::runJobInEstablishedExecutorContext(swift::Job*) + 444
8 libswift_Concurrency.dylib 0x62514 swift_job_runImpl(swift::Job*, swift::SerialExecutorRef) + 144
9 libdispatch.dylib 0x15ec0 _dispatch_root_queue_drain + 392
10 libdispatch.dylib 0x166c4 _dispatch_worker_thread2 + 156
11 libsystem_pthread.dylib 0x3644 _pthread_wqthread + 228
12 libsystem_pthread.dylib 0x1474 start_wqthread + 8
I have an attributedString with 100 NSTextAttachments(contains image of 400kb). When i scroll the textview, it is lagging, When i did the same in textkit 1, it is butter smooth. It can be because of how textkit 1 & 2 layout the elements.
let attachment = NSTextAttachment()
attachment.image = UIImage(named: "image2")
let attachmentString = NSAttributedString(attachment: attachment)
let mutableAttributedString = NSMutableAttributedString(attributedString: textView.attributedText)
for _ in 0...100 {
mutableAttributedString.append(NSAttributedString(string: "\n"))
mutableAttributedString.append(attachmentString)
}
textView.attributedText = mutableAttributedString
How to handle images in textkit 2 so that it feels smooth while scrolling textview?
Is there some reason UIKit's and AppKit's animate(with:changes:completion:) methods are marked deprecated in iOS 18 when they were also first made available in iOS18? If they are indeed already deprecated, is there a replacement method we are supposed to use? This method allows the developer to use SwiftUI animations to animate UIKit and AppKit views.
Cell Registration
lazy var headerCell: UICollectionView.SupplementaryRegistration<UICollectionReusableView> = .init(elementKind: UICollectionView.elementKindSectionHeader) { supplementaryView, elementKind, indexPath in }
and
Cell Dequeue
datasource.supplementaryViewProvider = { [weak self] collectionView, kind, indexPath in return collectionView.dequeueConfiguredReusableSupplementary(using: headerCell, for: indexPath) }
I am registering a collectionview cell or collwctionview reusable view as lazy variable. It causes a crash like
Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Attempted to dequeue a supplementary view using a registration that was created inside -collectionView:viewForSupplementaryElementOfKind:atIndexPath: or inside a UICollectionViewDiffableDataSource supplementary view provider. Creating a new registration each time a supplementary view is requested will prevent reuse and cause created supplementary views to remain inaccessible in memory for the lifetime of the collection view. Registrations should be created up front and reused. Registration: <UICollectionViewSupplementaryRegistration: 0x600001798a00>
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()
}
}
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
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
I have a SwiftUI View I've introduced to a UIKit app, using UIHostingController. The UIView instance that contains the SwiftUI view is animated using auto layout constraints. In this code block, when a view controller's viewDidAppear method I'm creating the hosting controller and adding its view as a subview of this view controller's view, in addition to doing the Container View Controller dance.
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
let hostingViewController = UIHostingController(rootView: TestView())
hostingViewController.view.translatesAutoresizingMaskIntoConstraints = false
addChild(hostingViewController)
view.addSubview(hostingViewController.view)
let centerXConstraint = hostingViewController.view.centerXAnchor.constraint(equalTo: view.centerXAnchor)
let topConstraint = hostingViewController.view.topAnchor.constraint(equalTo: view.topAnchor)
widthConstraint = hostingViewController.view.widthAnchor.constraint(equalToConstant: 361)
heightConstraint = hostingViewController.view.heightAnchor.constraint(equalToConstant: 342)
NSLayoutConstraint.activate([centerXConstraint, topConstraint, widthConstraint, heightConstraint])
hostingViewController.didMove(toParent: self)
self.hostingViewController = hostingViewController
}
I add a button to the UI which will scale the UIHostingViewController by adjusting its height and width constraints. When it's tapped, this action method runs.
@IBAction func animate(_ sender: Any) {
widthConstraint.constant = 120.3
heightConstraint.constant = 114.0
UIView.animate(withDuration: 0.5) {
self.view.layoutIfNeeded()
}
}
The problem is, the SwiftUI view's contents "jump" at the start of the animation to the final height, then animate into place. I see this both using UIView.animate the UIKit way, or creating a SwiftUI animation and calling `UIView.
What else do I need to add to make this animate smoothly?
I want to add a tool bar (setting search )to my app just like the apple file app using pure swiftUI, is it possible, if not, can i using a UIKit to implement it.
struct MainView: View {
var body: some View {
TabView {
Tab("View 1", systemImage: "square.grid.3x2") {
View1()
}
Tab("View 2", systemImage: "square.grid.2x2") {
View2()
}
}
.tabViewStyle(.sidebarAdaptable)
}
in iOS, user can set focus on UItextField and tapping a key in the virtual keyboard updates the text in the textfield. This user action causes the relevant delegates of UITextFieldDelegate to get invoked, i.e the handlers associated with action of user entering some text in the textfield.
I m trying to simulate this user action where I am trying to do this programatically. I want to simulate it in a way such that all the handlers/listeners which otherwise would have been invoked as a result of user typing in the textfield should also get invoked now when i am trying to do it programatically. I have a specific usecase of this in my application.
Below is how I m performing this simulation.
I m manually updating the text field associated(UITextField.text) and updating its value.
And then I m invoking the delegate manually as textField.delegate?.textField?(textField, shouldChangeCharactersIn: nsRange, replacementString: replacementString)
I wanted to know If this is the right way to do this. Is there something better available that can be used, such that simulation has the same affect as the user performing the update?
In macOS application, we are using SwiftUI as an entry point to our application and attaching appdelegate using NSApplicationDelegateAdaptor.
We are using NSViewControllerRepresentable to add a View Controller to the hiracrchy so that we can store intance of viewcontroller and add content to it programatically .
@main
struct TWMainApp: App {
@NSApplicationDelegateAdaptor private var appDelegate: TWAppDelegate
internal var body : some Scene {
TWInitialScene ()
}
}
TWInitialScene :
public struct TWInitialScene : Scene {
public var body : some Scene {
WindowGroup {
TWInitialView ()
}
}
}
TWInitialView :
struct TWInitialView : View {
@Environment(\.scenePhase) private var scenePhase
var body : some View {
TWAppKitToSwiftUIBridge ()
}
}
TWAppKitToSwiftUIBridge :
struct TWNSKitToSwiftUIBridge : NSViewControllerRepresentable {
func makeNSViewController(context: Context) -> TWNSViewController {
let view_hierarchy : TWNSViewController
view_hierarchy = TWStaticContext.sViewController
return view_hierarchy
}
func updateNSViewController(_ nsViewController: TWNSViewController, context: Context) {
}
}
@objc
public class TWStaticContext : NSObject
{
public static let sViewController = TWNSViewController ()
public override init () {}
@objc
public static func GetViewController () -> TWNSViewController
{
return TWStaticContext.sViewController
}
}
public class TWNSViewController : NSViewController {
override public func viewDidLoad ()
{
super.viewDidLoad ()
}
}
To add content to the hirarchy we are accessing viewcontroller's intance and adding content to it like this :
public func PaintInitialScreen () {
let label = NSTextField(labelWithString: "TW window")
label.frame = NSRect(x: 100, y: 200, width: 200, height: 200)
// Adding content to viewcontroller
TWStaticContext.sViewController.view.addSubview(label)
}
We are using this approach because we have a contraint in our application that we have to update UI programatically and on compile time we dont know what we want to show . We will be adding content on runtime based on how many button we want, what label we want , where to place it etc.
When we were using purely appKit application, doing things programatically was simple but since SwiftUI is a declarative application we have to use above approach.
Rational for shifting to SwiftUI entry point is that we want our application to be future safe and since apple is more inclined to SwiffUI, we want to design our entry flow to use SwiftUI entry point . And SwiftUI being declarative, we are using appKit to add content to hiracrchy programtically.
We have used similar apprach in iOS also , where are using UIApplicationDelegateAdaptor inplace of NSApplicationAdaptor . And UIViewControllerReprestable in place of NSViewControllerRepresentable.
Is this right approach to use ?