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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macOS Menu disappears when converting from NSApplicationActivationPolicyAccessory to NSApplicationActivationPolicyRegular if display disconnected and reconnected
I'm not quite sure where the problem is, but I will describe what I am doing to recreate the issue, and am happy to provide whatever information I can to be more useful. I am changing the ActivationPolicy for my app in order to make it unobtrusive when in the background (e.g. hiding it from the dock and using only a menu bar status item). When the user activates the app with a hotkey, it changes from NSApplicationActivationPolicyAccessory back to NSApplicationActivationPolicyRegular. This allows normal usage (dock icon, menu bar, etc.) This works fine, except in a rare situation which I finally just tracked down. If there is a window open in the app and I use the hotkey to convert back to an accessory, and then disconnect and reconnect the display on which the app was previously displayed, when I convert the app back to "regular mode", the menu bar has disappeared (and I am left with an empty space at the top of the screen). I can also trigger this bug by having the display in question briefly mirror the other display (effectively "orphaning" the hidden app), and then restoring the original side-by-side configuration before activating the app again. The app otherwise works, but the menu bar is missing. Switching back and forth with other apps does not fix the problem. Quitting and restarting the app resolves the issue. As does disabling the accessory only mode and forcing the app to always remain in "regular mode" with a dock icon (there is a preference for this in my app). Once fixed, I can then re-enable the "accessory mode" and all is well until the bug is triggered again. The bug would normally occur quite sporadically, presumably requiring a particular combination of changing Spaces or displays, or having the computer go to sleep while this app was in accessory mode. Thus far, the above is the only way I have found that can replicate this issue on demand. If I close all windows before hiding the app, then it works fine when I revert to "regular mode". It only happens if there is a window open at the time. Using applicationDidChangeScreenParameters: on my AppDelegate indicates that there is a change in screen, and logging window.screen.frame for each open window in [NSApp orderedWindows] shows that the size changes from e.g. 1920x1080 to 0x0 and back while the display is disconnected or mirrored. There is also an error in the console in Xcode when this happens -- invalid display identifier <some UUID>. I have tried various options for window collectionBehavior, as well as various settings for Spaces (which I normally use). None of these changes has fixed the behavior thus far. I use [NSApp hide:self]; from my AppDelegate to hide the app, and [[NSRunningApplication currentApplication] activateWithOptions:NSApplicationActivateAllWindows];[NSApp unhide:self]; to bring it back to the front. I welcome any ideas for things to chase down, or requests for more specific information that would be useful. Thank you! Fletcher
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478
Feb ’25
How to programmatically set cursor position of a text field in SwiftUI
I would like to understand how to programmatically set the position of a cursor in a SwiftUI TextField. In UIKit this can be done using the selectedTextRange property, but I couldn't find a similar way to achieve this with pure SwiftUI. I want to figure out something like setCursorPosition (index:) - maybe by tracking the position in a @State or any other way. I understand that I can do this using UIViewRepresentable but I am looking for a pure SwiftUI solution and wanted to know if there is any.
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Mar ’25
SwiftUI textfield inside sheet produces extra padding when keyboard shown
I want to present a textfield inside a sheet. However when the keyboard is shown, the sheet view produces extra padding even though I explicitly set the frame of the textfield and the presentationDent to be the exact same height. Reproducible example: struct ContentView: View { @State var showSheet: Bool = false @State var text = "" var body: some View { VStack { Image(systemName: "globe") .imageScale(.large) .foregroundStyle(.tint) Text("Hello, world!") Button { showSheet.toggle() } label: { Text("Show Sheet") } } .sheet(isPresented: $showSheet) { TextField("Hello", text: $text) .frame(height: 44) .background(.red) .presentationDetents([.height(44)]) .presentationDragIndicator(.hidden) } } } Does anyone know how to resolve this issue?
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488
Feb ’25
SwiftData predicate for many to many relationships?
Hello, I have a Task model in my application which has an optional many to many relationship to a User model. task.assignedUsers user.tasks I am looking to construct a SwiftData predicate to fetch tasks which either have no assigned users or assigned users does not contain specific user. Here is a partially working predicate I have now: static func assignedToOthersPredicate() -> Predicate<Task> { let currentUserGUID = User.currentUserGUID return #Predicate<Task> { task in task.assignedUsers.flatMap { users in users.contains(where: { $0.guid != currentUserGUID }) } == true } } This only returns tasks assigned to others, but not those which have no assigned users. If combine it with this: static func notAssignedPredicate() -> Predicate<Task> { return #Predicate<Task> { task in task.assignedUsers == nil } } Then I get a run time crash: "to-many key not allowed here" What is the proper way to do this? Thanks.
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349
Mar ’25
AppKit: presentAsModalWindow doesn't center the presented window on macOS 15
When I present a view controller, whose view is a SwiftUI View, via presentAsModalWindow(_:) the presented window is no longer centered horizontally to the screen, but rather its origin is there. I know this issue occurs for macOS 15.2+, but can't tell if it is from 15.0+. I couldn't find any documentation on why was this changed. Here's an example code that represents my architecture: class RootViewController: NSViewController { private lazy var button: NSButton = NSButton( title: "Present", target: self, action: #selector(presentView)) override func viewDidLoad() { super.viewDidLoad() // Add button to tree } @objc func presentView() { presentAsModalWindow(PresentedViewController()) } } class PresentedViewController: NSViewController { override loadView() { view = NSHostingView(rootView: MyView()) } } struct MyView: View { /* impl */ }
Topic: UI Frameworks SubTopic: AppKit Tags:
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193
Mar ’25
Custom keypad touchUpInside events not working in iOS18
I have a custom keypad to accept numeric input for iPads that I have been using for many years now. This is longstanding working code. With iOS 18 the touchUpInside (and other) events in the underlying Objective-C modules are not called in the file owner module when activated from the interface. The buttons seem to be properly activated based on the visual cues (they change colors when pressed). This is occurring in both simulators and on hardware. Setting the target OS version does not help. What could the cause and/or solution of this be?
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Mar ’25
UIDocumentPickerViewController of type pdf cannot pick pdf in simulator
I'm having this problem, with this code: let docPicker = UIDocumentPickerViewController(forOpeningContentTypes: [ .pdf ]) docPicker.delegate = self docPicker.modalPresentationStyle = .currentContext view.window?.rootViewController?.present(docPicker, animated: true, completion: nil) but then when I open the simulator and click the button that calls to the method that has this code... Cannot pick the pdf document. Testing in browserstack with real devices is working, but it's a very slow process, why I cannot use simulators to make work this?
Topic: UI Frameworks SubTopic: UIKit Tags:
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370
Feb ’25
iOS 18.4 App updates crashes the widget and the only solution is to restart the device or change the device language
App update in which there were no changes regarding the widget. Just after it updated, the widget turns black in some cases. It also appears black in the widget gallery. Removing and adding it again did not work in this case, only after an iOS restart it works fine again This is the log 2025-03-20 02:14:05.961611 +0800 Content load failed: unable to find or unarchive file for key: [com.aa.bb::com.aa.bb.widget:cc_widget:systemMedium::360.00/169.00/23.00:(null)~(null)] on no host. The session may still produce one shortly. Error: Using url file:///private/var/mobile/Containers/Data/PluginKitPlugin/51C5E4F2-6F1F-4466-A428-73C73B9CC887/SystemData/com.apple.chrono/placeholders/cc_widget/systemMedium----360.00w--169.00h--23.00r--1f--0.00t-0.00l-0.00b0.00t.chrono-timeline ... Error Domain=NSCocoaErrorDomain Code=4 "file“systemMedium----360.00w--169.00h--23.00r--1f--0.00t-0.00l-0.00b0.00t.chrono-timeline”not exist。" UserInfo={NSFilePath=/private/var/mobile/Containers/Data/PluginKitPlugin/51C5E4F2-6F1F-4466-A428-73C73B9CC887/SystemData/com.apple.chrono/placeholders/cc_widget/systemMedium----360.00w--169.00h--23.00r--1f--0.00t-0.00l-0.00b0.00t.chrono-timeline, NSUnderlyingError=0xa693d3a80 {Error Domain=NSPOSIXErrorDomain Code=2 "No such file or directory"}}
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121
Mar ’25
NSTextAttachment lagging in textkit 2
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?
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Feb ’25
alternateIconName
I config of an alternate icon on the App Store Connect product page optimization. After the app launches, can I retrieve the name of this configured icon through UIApplication.shared.alternateIconName?
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Mar ’25
Is it possible to automatically flip device orientation?
Hello togehter, i do have the following question. If I have my App run in landscape mode and a sheet view get's called, will it be possible to switch automatically from landscape mode in portrait mode and fix this device orientation? Once the sheet view get's dismissed or closed, the original view will come back and the device orientation shall switch back to landscape mode. Thanks you so much for your help!
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249
Feb ’25
Entire view re-renders when updating dictionary
I'm trying to create a form which reads and writes data to a dictionary. when I type something in a field whole form seems to update. Is there anyway to only update the field I'm typing? Android compose have something called SnapshotStateMap which allows smart re-rendering.
Topic: UI Frameworks SubTopic: SwiftUI
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120
Mar ’25
Seeking KeyboardLayout ID for All Native Keyboards in iOS and macOS
Hello everyone, I am currently working on a project that requires me to programmatically manage keyboard layouts on both iOS and macOS devices. I'm looking for a comprehensive list of KeyboardLayout ID values for all the native keyboard layouts available in both iOS and macOS. While I can extract some of this information from the /System/Library/Keyboard Layouts/ directory on macOS, I cannot extract all without adding every keyboard layout active, having a complete and pre-compiled list would be immensely helpful. Does anyone here have such a list or know where I might find one? Any guidance on this matter would be greatly appreciated. Thank you in advance for your assistance! JJ
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958
Mar ’25
Switching my App from UserDefaults to CoreData and CloudKit
I need someone to tell me if it’s possible to switch my whole app from user defaults to core data. My app is pretty data and calculation intensive and I don’t think user defaults is enough to store and retrieve all the data. Also, I need my app to be iCloud enabled so that the user can access their data from any of their devices. (I’m very new to this coding thing and I’ve been using AI for my entire app)
Topic: UI Frameworks SubTopic: SwiftUI
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199
Mar ’25
@State memory leak Xcode 16.2
Hi, A class initialized as the initial value of an @State property is not released until the whole View disappears. Every subsequent instance deinitializes properly. Am I missing something, or is this a known issue? struct ContentView: View { // 1 - init first SimpleClass instance @State var simpleClass: SimpleClass? = SimpleClass(name: "First") var body: some View { VStack { Text("Hello, world!") } .task { try? await Task.sleep(for: .seconds(2)) // 2 - init second SimpleClass instance and set as new @State // "First" should deinit simpleClass = SimpleClass(name: "Second") // 3 - "Second" deinit just fine simpleClass = nil } } } class SimpleClass { let name: String init(name: String) { print("init: \(name)") self.name = name } deinit { print("deinit: \(name)") } } output: init: First init: Second deinit: Second Thanks
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288
Feb ’25
`.refreshable(action:)` `s indicator will not dismiss after when app into backgound (iOS 17.1)
Hello, I am encountering an issue with .refreshable(action:) in ScrollView. The refresh action works as expected when performing a pull-to-refresh. However, if I put the app in the background while the refresh operation is in progress, the refresh indicator remains visible on the screen when I return to the foreground and does not disappear. Once I interact with the ScrollView after returning to the foreground, the refresh indicator disappears, and the functionality itself is not affected. I initially attempted to resolve this issue by triggering a view redraw when scenePhase changes. However, since my app presents the SwiftUI view using UIHostingController, the scenePhase from the environment does not seem to function correctly. This issue occurs on iOS 17.1 but does not appear on iOS 16.1.1. Is there a known way to resolve this unexpected behavior? Below is a simplified sample code (some parts are omitted): struct MyView: View { @StateObject private var model: MyModel var body: some View { ScrollView { // My ContentViews... } .refreshable { do { try await self.model.refresh() } catch { // Handle error } } } } @MainActor final class MyModel: ObservableObject { // === Some Code === func refresh() async throws { let data = try await self.fetchData() self.data = Array(OrderedSet(data)) } } I apologize for any mistakes in my English, as I am using a translation tool. Thank you in advance for your help! Best regards,
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Mar ’25
PhoneSceneDelegate white screen
I am currently implementing multiple scenes in my React Native / Swift application (one scene for the phone and one scene for CarPlay). I am facing an issue where one scene renders completely white (on the iPhone) but I can see in the console that the code is running (for example if I add a console.log to the App.tsx I can see that console log happen in XCode). There are no errors when building the app in XCode, and testing with the simulator CarPlay appears to render the correct output, but there is no component being rendered on the simulated phone screen (just white). AppDelegate.swift import CarPlay import React import React_RCTAppDelegate import ReactAppDependencyProvider import UIKit @main class AppDelegate: RCTAppDelegate { var rootView: UIView?; static var shared: AppDelegate { return UIApplication.shared.delegate as! AppDelegate } override func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey : Any]? = nil) -> Bool { self.moduleName = "appName" self.dependencyProvider = RCTAppDependencyProvider() self.initialProps = [:] self.rootView = self.createRootView( with: RCTBridge( delegate: self, launchOptions: launchOptions ), moduleName: self.moduleName!, initProps: self.initialProps! ); return super.application(application, didFinishLaunchingWithOptions: launchOptions) } override func application(_ application: UIApplication, configurationForConnecting connectingSceneSession: UISceneSession, options: UIScene.ConnectionOptions) -> UISceneConfiguration { if (connectingSceneSession.role == UISceneSession.Role.carTemplateApplication) { let scene = UISceneConfiguration(name: "CarPlay", sessionRole: connectingSceneSession.role) scene.delegateClass = CarSceneDelegate.self return scene } let scene = UISceneConfiguration(name: "Phone", sessionRole: connectingSceneSession.role) scene.delegateClass = PhoneSceneDelegate.self return scene } override func application(_ application: UIApplication, didDiscardSceneSessions sceneSessions: Set<UISceneSession>) {} override func sourceURL(for bridge: RCTBridge) -> URL? { self.bundleURL() } override func bundleURL() -> URL? { #if DEBUG RCTBundleURLProvider.sharedSettings().jsBundleURL(forBundleRoot: "index") #else Bundle.main.url(forResource: "main", withExtension: "jsbundle") #endif } } PhoneSceneDelegate.swift import Foundation import UIKit import SwiftUI class PhoneSceneDelegate: UIResponder, UIWindowSceneDelegate { var window: UIWindow?; func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) { if session.role != .windowApplication { return } guard let appDelegate = (UIApplication.shared.delegate as? AppDelegate) else { return } guard let windowScene = (scene as? UIWindowScene) else { return } let rootViewController = UIViewController() rootViewController.view = appDelegate.rootView; let window = UIWindow(windowScene: windowScene) window.rootViewController = rootViewController self.window = window window.makeKeyAndVisible() } } App.tsx import React, {useEffect, useState} from 'react'; import type {PropsWithChildren} from 'react'; import {CarPlay, ListTemplate} from 'react-native-carplay'; import { ScrollView, StatusBar, StyleSheet, Text, useColorScheme, View, } from 'react-native'; import { Colors, DebugInstructions, Header, LearnMoreLinks, ReloadInstructions, } from 'react-native/Libraries/NewAppScreen'; type SectionProps = PropsWithChildren<{ title: string; }>; function Section({children, title}: SectionProps): React.JSX.Element { const isDarkMode = useColorScheme() === 'dark'; return ( <View style={styles.sectionContainer}> <Text style={[ styles.sectionTitle, { color: isDarkMode ? Colors.white : Colors.black, }, ]}> {title} </Text> <Text style={[ styles.sectionDescription, { color: isDarkMode ? Colors.light : Colors.dark, }, ]}> {children} </Text> </View> ); } function App(): any { // React.JSX.Element const isDarkMode = useColorScheme() === 'dark'; const backgroundStyle = { backgroundColor: isDarkMode ? Colors.darker : Colors.lighter, }; const [carPlayConnected, setCarPlayConnected] = useState(CarPlay.connected); useEffect(() => { function onConnect() { setCarPlayConnected(true); CarPlay.setRootTemplate(new ListTemplate(/** This renders fine on the CarPlay side */)); } function onDisconnect() { setCarPlayConnected(false); } CarPlay.registerOnConnect(onConnect); CarPlay.registerOnDisconnect(onDisconnect); return () => { CarPlay.unregisterOnConnect(onConnect); CarPlay.unregisterOnDisconnect(onDisconnect); }; }); if (carPlayConnected) { console.log('car play connected'); } else { console.log('car play not connected'); } const safePadding = '5%'; // This doesn't render on the phone? return ( <View style={backgroundStyle}> <StatusBar barStyle={isDarkMode ? 'light-content' : 'dark-content'} backgroundColor={backgroundStyle.backgroundColor} /> <ScrollView style={backgroundStyle}> <View style={{paddingRight: safePadding}}> <Header/> </View> <View style={{ backgroundColor: isDarkMode ? Colors.black : Colors.white, paddingHorizontal: safePadding, paddingBottom: safePadding, }}> <Section title="Step One"> Edit <Text style={styles.highlight}>App.tsx</Text> to change this screen and then come back to see your edits. </Section> <Section title="See Your Changes"> <ReloadInstructions /> </Section> <Section title="Debug"> <DebugInstructions /> </Section> <Section title="Learn More"> Read the docs to discover what to do next: </Section> <LearnMoreLinks /> </View> </ScrollView> </View> ); } const styles = StyleSheet.create({ sectionContainer: { marginTop: 32, paddingHorizontal: 24, }, sectionTitle: { fontSize: 24, fontWeight: '600', }, sectionDescription: { marginTop: 8, fontSize: 18, fontWeight: '400', }, highlight: { fontWeight: '700', }, }); export default App; I have been attempting to get this working now for some 20+ hours with no luck with searching for answers elsewhere. I am very new to building apps with React Native and Swift so could do with some support.
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356
Mar ’25
Unexpected onAppear behavior in NavigationStack with ViewThatFits
Hello, My goal is to have a NavigationStack whose root view is determined based on its height and width. To do so, I'm using ViewThatFits, which should choose the right view to display. It is working fine, but unexpectedly both views trigger onAppear, whereas only the appropriate one should. This causes the logic in both closures to be executed, which is not intended. The code below demonstrates the problem: struct NavigationStackContentView: View { var body: some View { NavigationStack { ViewThatFits(in: .vertical) { Color.yellow .onAppear { print("|-> on appear: yellow") } .onDisappear { print("|-> on disappear: yellow") } Color.red .frame(width: 1500, height: 1500) .onAppear { print("|-> on appear: red") } .onDisappear { print("|-> on disappear: red") } } } } } this produces: |-> on appear: red |-> on disappear: red |-> on appear: yellow When ViewThatFits is not nested within NavigationStack, the problem does not occur — only the yellow view (in this sample) triggers onAppear, which is the expected behavior. I also checked the macOS version, and the problem does not occur at all, whether within NavigationStack or not. This example is simple and demonstrates that the larger view is the second one. When I switch their places, the problem does not occur because it recognizes that the first view would not fit at this point. However, in my case I will have these views without knowing which one will not fit, so switching their order is not a viable solution if this works without NavigationStack. Am I doing something wrong, or is this a bug? // iOS: 18.3.1 Xcode: 16.2
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Mar ’25
detecting modifier keys using UITextFieldDelegate protocol
I have a UITextField in my application, and I want to detect all the keys uniquely to perform all relevant task. However, there is some problem in cleanly identifying some of the keys. I m not able to identify the backspace key press in the textField(_:shouldChangeCharactersIn:replacementString:) method. Also I don't know how to detect the Caps Lock key. I am intending to so this because I want to perform some custom handling for some keys. Can someone help me with what is the way of detecting it under the recommendation from apple. Thanks in advance. Note: checking for replacementString parameter in shouldChangeCharactersIn method for empty does not help for backspace detection as it overlaps with other cases.
Topic: UI Frameworks SubTopic: UIKit Tags:
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150
Mar ’25