Hi, I want to run the live preview on my iPhone, but I received the error message that the app failed to launch. How can I fix this? Everything is made with SwiftUI Thanks

class ViewModel : NSObject, ObservableObject, ASWebAuthenticationPresentationContextProviding { private var authSession: ASWebAuthenticationSession? func signInWithOpenID(provider: OAuthProvider) { let url = getOIDCAuthenticationURL(provider: provider) authSession?.cancel() authSession = nil authSession = ASWebAuthenticationSession(url: url, callbackURLScheme: "com.ninjanutri") { callbackURL, error in if let error = error { print("Error: \(error.localizedDescription)") return } guard let callbackURL = callbackURL else { return } guard let idToken = callbackURL.valueOf("id_token") else { return } self.signInWithIdToken(provider: provider, idToken: idToken) } authSession?.prefersEphemeralWebBrowserSession = false authSession?.presentationContextProvider = self authSession?.start() } public func presentationAnchor(for session: ASWebAuthenticationSession) -> ASPresentationAnchor { return ASPresentationAnchor() } } struct ContentView: View { @StateObject private var viewModel = ViewModel() var body: some View { Button { viewModel.signInWithOpenID(provider: .github) } label: { Text("Test") } } } when the prefersEphemeralWebBrowserSession is false, the alert and webview is totally working fine in Simulator and Real device, but not XCode Preview. Is this behaviour expected or it's a bug?

I recieve the error message "XOJITError: Could not create code file directory for session: Permission denied". I'm Using Xcode 16.2. It is an AppKit project using SwiftUI and it also happens if I create a clean project. Error log is attached. previews_diagnostics_summary.txt

Hello everyone, I've encountered an issue with SwiftUI Preview and would appreciate your help. Problem Description In a mixed Objective-C and Swift project, I'm experiencing the following situation with SwiftUI Preview: Crashes when previewing on a physical device The same code runs normally when launched directly through Xcode Project uses CocoaPods for dependency management with static frameworks Project Environment: Project Type: Mixed (Objective-C + Swift) Dependency Management: CocoaPods Dependency Type: Static frameworks Device: Physical device preview Steps to Reproduce: Write Preview code in SwiftUI file Select physical device as Preview device Click Preview button Application crashes

When working on my Xcode project and using Previews from time to time I find preview crashes and ens up with the image below. The UI is completely unresponsive and only way to bring it back I find is close and relaunch Xcode. Anyone else experience this - is there a known fix or a better way to "kick" preview to restart that doesn't involve full relaunch of XCode

Hi there, i just want to know, why my xcode is not showing any print in my Xcode, when i build it, it tell me "Ready to continue xx" but the result of my code doesnt appear in right panel

My preview crashed because it could not access my font resources. I am working on a Framework, and it seems that for frameworks, the resources are not copied into the app package of the preview. Investigation: I verified this by examining the contents of the preview: /Users/YOUR_NAME/Library/Developer/Xcode/UserData/Previews/Simulator Devices/DEVICE_UUID/data/Containers/Bundle/Application/APPLICATION_UUID/APPLICATION_NAME.app Make sure to replace "YOUR_NAME," "DEVICE_UUID," "APPLICATION_UUID," and "APPLICATION_NAME" with the actual names or UUIDs relevant to your specific situation. Now right-click on the app and select Show Package Contents. For previews that work correctly, the name of the associated app is used, and you will see all the resources in the package. However, my framework was not using the framework name. Instead, it was named XCPreviewAgent.app and did not contain any resources from my framework. Fix: As of November 2024 (Xcode 16.0 and Xcode 16.1), the fix is to use Legacy Preview Execution. In the menu, select Editor > Canvas > Legacy Preview Execution. Please leave a comment if this is fixed in a newer Xcode version.

I got a preview crash info as this: *** crashed due to fatalError in PersistentModel.swift at line 559. This KeyPath does not appear to relate RecordInfo to anything - \RecordInfo.<computed 0x00000001921dfb4e (Array<SomeInfo>)> If I change preview device to iPhoneSE, It is no crash. I think the reason is I have some dirty data in iPhone16 Pro preview device. If I'm right and how to delete it? Model of RecordInfo like this: @Model class RecordInfo { @Relationship(deleteRule: .cascade) var someInfo:[SomeInfo] } @Model class SomeInfo { var date: Date var info: String }

Views can be viewed on the canvas in XCode via the code below. #Preview { ContentView() } But how do I preview an App class in XCode? Background: I'd like to preview various settings done in the Scene of the App.

I'm trying to create a preview for my live activities when it's stale, so I created a preview provider. I followed some examples, but XCode says I'm missing preview context. Am I doing something wrong? I tried adding .previewContext(WidgetPreviewContext(family: .systemSmall)) but that doesn't seem to work.

I can't seem to access preview for any of my views in any of my swift projects at all (using Mac to code and using iPhone 16 pro as preview and simulation, simulation can work), even after restarting Mac and Xcode itself. The preview section has a popup saying "Cannot preview in this file, unexpected error occured" (for every file), please tell me what is wrong and help me solve it to see the preview, thank you! details

Hello, I recently decided to start learning how to code for iOS. I don't have much coding experience but I still wanted to explore it for fun at least. I downloaded Xcode on my Macbook, and opened a new iOS file after downloading iOS 18.1 so I could run the simulator/get a preview of my code. Even though I only had the basic "Hello World!" that is auto-generated in my code, the preview would never show and sat at a loading screen for multiple hours, saying "Preparing (Automatic) iPhone Simulator" at the top. There is probably a simple solution that I'm missing. I would appreciate any tips! Thanks.

The simulator will not work. No matter How much I restart, when I open my app, it tells me either Build succeeded but I see a loading bar or a loading automatic phone simulator but it never shows up like the line would. keep going in a loop, for example this is what it looks like,

Hello everyone, I’m currently developing my first VisionOS app in Xcode, starting with the default "Hello World" code provided when creating a new VisionOS Mixed Reality App. However, I’m facing some issues with performance and previewing that I can’t seem to resolve. When I load the preview, it takes an extremely long time, and sometimes it doesn’t load at all. Even when I try to run the app in the VisionOS Simulator, the simulator shows an endless black screen and never displays the intended view. I’ve made no changes to the code, so it’s purely the base setup. Here are my system details: Xcode version: 16.1, VisionOs 2.0; macOS version: 15.0.1; Hardware: MacBook Air 2020 M1 I’ve tried restarting Xcode and my machine, but the issue persists. Has anyone else faced similar problems or have any suggestions for fixing this? Or is my hardware simply too weak? Any help would be greatly appreciated! Thank you in advance!

I'm developing an app which supports for connect with an BLE device. There are some views for showing data from bluetooth. The code below for an example: @EnvironmentObject var bleManager: BLEManager // a class implemented CBCentralManagerDelegate var body: some View { // bleConnected is a CBPeripheral if let bleConnected = bleManager.bleConnected { if let services = bleConnected.services { ForEach(services, id:\.self) { service in // UI for print uuid, descriptions ... showServiceDescriptionView(services) if let characteristics = service.characteristics { ForEach(characteristics, id:\.self) { characteristic in // UI for print uuid, data for each characteristic showCharacteristicsDetailView(characteristic) } } } } } } } But it seems that Xcode Preview do not support connect to a real bluetooth device. So the preview window in Xcode will always be a empty view. I only can see the data on the real device. But it's important for me to design UI on the preview. So are there any method to mock a fake CBPeripheral in the Previewer? Or are there any other way to achieve this?

I'm using Xcode 16 and SwiftUI targeting iOS 18. I'm new to Core Data, and when I create a new project and select to use Core Data as storage, I get boilerplate code for it. The problem is that when I try to see the preview without any change to the code, I get a Fatal Error: CrashReportError: Fatal Error in Persistence.swift Test crashed due to fatalError in Persistence.swift at line 52. Unresolved error Error Domain=NSSQLiteErrorDomain Code=8 "(null)" UserInfo={NSFilePath=/Users/monni/Library/Developer/Xcode/UserData/Previews/Simulator Devices/D0D98B5B-7E6F-4DC3-B16A-34D6D2958558/data/Containers/Data/Application/A98879A6-46F5-4E29-B2D7-AD294F1EFFD0/Library/Application Support/Test.sqlite, NSSQLiteErrorDomain=8}, ["NSSQLiteErrorDomain": 8, "NSFilePath": /Users/monni/Library/Developer/Xcode/UserData/Previews/Simulator Devices/D0D98B5B-7E6F-4DC3-B16A-34D6D2958558/data/Containers/Data/Application/A98879A6-46F5-4E29-B2D7-AD294F1EFFD0/Library/Application Support/Test.sqlite] When I try to open the SQLite database there are no entities in it. I have also tried xcrun simctl --set previews delete all, but with no luck.

My iOS (iPhone/iPad/Mac Catalyst) app has a relatively complex authentication flow, primarily required due to it being an API client. Several of my views have .task modifiers that begin executing code when the views are created. After moving to iOS 18 and Xcode 16, when running in the Simulator, I began noticing my workflow was breaking as views were being created out of sequence... but not by me 🤯 Here is an example stack when I place a breakpoint inside of this view's .task. From my logging (and this stack) I can verify I am not creating this view. This view has no preview associated with it, and there are no previews up the view hierarchy from it either. This happens in the Simulator only The only clue I have to go on is this line of text which is present at the top of what looks like ASM when I click on the (5) line in the stack above. SwiftUI`(1) await resume partial function for dispatch thunk of static SwiftUI.PreviewModifier.makeSharedContext() async throws -> τ_0_0.Context: If this (or any hierarchical view) used Previews, I'd remove them to see if it had an effect, but they don't! I'm at a loss on what to do here...

I've recently started learning how to make IOS apps, but when trying to load the preview, it just shows the loading animation indefinitely. I am running xcode 15.2 (because my mac is a bit old and doesn't run the latest version) I have tried using version 15.1 but it still doesn't work, only works when I go down to version 14.3.1, but that changes the swift code.

Hello! SwiftUI preview does not work. I tried different versions of Xcode, deleting the "Developer" folders, clearing the "Build" folder from the project in Xcode, reinstalling Command Line Tools and Developer Tools. I think that the error appeared after I cleaned Xcode with CleanMyMacX, before that the preview worked. -MacBook Pro (15-inch, Mid 2012) -macOS Catalina 10.15.7 -Xcode 12.3 Thanks for the feedback!

Hi everyone, I’m encountering a strange issue when trying to archive my iOS app for App Store distribution. The project builds and runs fine on “Any iOS Device (arm64)”, but when I try to Product → Archive, I get multiple errors related to preview sections in my SwiftUI view files. The app uses camera for photo and video capture. Errors: • Cannot find 'PreviewCameraModel' in scope • Cannot infer contextual base in reference to member 'video' • Cannot infer contextual base in reference to member 'classify' These errors only appear in code sections inside the #Preview blocks in SwiftUI files. Additionally: When I click on an error in the Issue Navigator, the file shows the error momentarily but it disappears after less than a second. The total error count decreases temporarily, but then it returns to the original number when clicking on other errors. Build and Run works fine without any issues on devices and simulators, but these errors block the archiving process. Workaround: For now, I’ve resolved the issue by using #if DEBUG to exclude the preview code from release builds, but I’d prefer a cleaner solution if one exists. System Details: Xcode: 16.0 iOS Deployment Target: 16+ Swift: 5 Architecture: arm64 Has anyone encountered this issue or found a better way to handle SwiftUI preview code when archiving? Any advice on fixing this or insights into why the errors behave inconsistently during the archiving process would be appreciated. Thanks in advance!