Xcode Previews

RSS for tag

Create an app UI and configure almost everything your users see using Xcode Previews.

Posts under Xcode Previews tag

93 Posts

Post

Replies

Boosts

Views

Activity

SwiftUI Preview Runtime linking failure
I'm using GoogleMaps in my project. Legacy preview works well but new preview (Xcode 16.3.1 beta) produces error. It doesn't seem to find Googlemaps.a. == PREVIEW UPDATE ERROR: FailedToLaunchAppError: Failed to launch *** ================================== | [Remote] JITError | | ================================== | | | [Remote] CouldNotLoadInputStaticArchiveFile: Could not load static archive during preview: /Users/***/Library/Developer/Xcode/DerivedData/BOA-eiluspltxasszsfkpqrnnsxsjhth/Build/Products/Debug_BOA_Inhouse-iphonesimulator/GoogleMaps.a | | | | path: /Users/***/Library/Developer/Xcode/DerivedData/BOA-eiluspltxasszsfkpqrnnsxsjhth/Build/Products/Debug_BOA_Inhouse-iphonesimulator/GoogleMaps.a | | | | ================================== | | | | | [Remote] XOJITError | | | | | | XOJITError: arm64 slice of /Users/***/Library/Developer/Xcode/DerivedData/BOA-eiluspltxasszsfkpqrnnsxsjhth/Build/Products/Debug_BOA_Inhouse-iphonesimulator/GoogleMaps.a does not contain an archive
12
0
1.1k
Jun ’25
Question about using @Previewable
This is an issue that occurred while using SwiftUI. Cannot find '$state' in scope The other view finds properties normally. May I know why the error is occurring? The following code is the full text of the code that causes problems. import SwiftUI @Observable class HomeState { var title: String = "Home" } struct HomeView: View { @Binding var state: HomeState var body: some View { Text(state.title) } } #Preview { @Previewable @State var state: HomeState = .init() HomeView(state: $state) /// Error: Cannot find '$state' in scope } The same error occurs when using the String type rather than the object. What did I do wrong?
2
1
228
Mar ’25
SwiftUI Preview Fails to Load While Project Builds and Runs Fine: Alamofire Module Map Issue
I'm having an issue specifically with SwiftUI previews in my iOS project. The project builds and runs fine on devices and simulators (in Rosetta mode), but SwiftUI previews fail to load in both Rosetta and native arm64 simulator environments. The main error in the preview is related to the Alamofire dependency in my SiriKit Intents extension: Module map file '[DerivedData path]/Build/Products/Debug-iphonesimulator/Alamofire/Alamofire.modulemap' not found This error repeats for multiple Swift files within my SiriKit Intents extension. Additionally, I'm seeing: Cannot load underlying module for 'Alamofire Environment Xcode version: 16.2 macOS version: Sonoma 14.7 Swift version: 6.0.3 (swiftlang-6.0.3.1.10 clang-1600.0.30.1) Dependency management: CocoaPods Alamofire version: 5.8 My project is a large, older codebase that contains a mix of UIKit, Objective-C and Swift Architecture Issue: The project only builds successfully in Rosetta mode for simulators. SwiftUI previews are failing in both Rosetta and native arm64 environments. This suggests there may be a fundamental issue with how the preview system interacts with the project's architecture configuration. What I've Tried I've attempted several solutions without success: Cleaning the build folder (⇧⌘K and Option+⇧⌘K) Deleting derived data Reinstalling dependencies Restarting Xcode Removing and re-adding Alamofire
1
0
91
Mar ’25
Failed to Install Preview App on iPhone in Xcode Previews (HelloWorldApp)
Hi everyone, I'm encountering an issue when trying to run Xcode Previews for my HelloWorldApp on a real iPhone device. The app fails to install, and I get the following error message: Development Environment: Xcode Version: 16C5032a macOS Version: 23H420 Test Device (iPhone): iPhone 12 mini, iOS 15.5 (19F77) MacBook: MacBook Air (M1, arm64e) Error Message: Whenever I attempt to preview the app using SwiftUI Previews on my iPhone (iPhone của Định), I get the following installation error: FailedToInstallAppError: Failed to install ”HelloWorldApp.app” Could not install the preview host ”HelloWorldApp.app” on iPhone của Định Here’s part of the detailed log: agentBundle = com.DihNgx.HelloWorldApp { url: file:///Users/dihngx/Library/Developer/Xcode/DerivedData/HelloWorldApp-eyeszqttvaydocbdmoiwcczlazrt/Build/Intermediates.noindex/Previews/iphoneos/HelloWorldApp/Products/Debug-iphoneos/HelloWorldApp.app signingInformation: Code Signing { identifier: com.DihNgx.HelloWorldApp identity: A9A830FA23874E2047C974D6621D441EB9CBC7CC hasGetTaskAllow: true isSandboxed: false } } Device Information: Device Name: iPhone của Định Device Identifier: 00008101-001C482922C0001E iOS Version: 15.5 Provisioning profile installed: "iOS Team Provisioning Profile: com.DihNgx.HelloWorldApp" Steps I’ve already tried (but the issue persists): Ensured that Xcode recognizes the iPhone and that the device is connected properly. Checked Code Signing and Provisioning Profile (no issues were shown). Cleaned the build folder (Cmd + Shift + K) and deleted Derived Data. I’d really appreciate any advice or suggestions on how to solve this issue. Has anyone else faced a similar error or knows how to fix this? Thanks so much in advance!
1
0
96
Mar ’25
SortDescriptor from a generic method crashes Xcode Previews but not Simulator.
I attempted to create a SortDescriptor using a method in enum to sort various different models in SwiftUI lists. But it causes crashes in Xcodes previews but not in the simulator, and I don't know why. Maybe someone could suggest changes. extension Item:ListSorting {} //List sorting is a protocol given to various Models enum ListSortingStyle<T>:String,CaseIterable where T:ListSorting { case alphabetical = "A…Z" case alphabeticalReverse = "Z…A" case createDate = "Newest" case createDateReverse = "Oldest" case editDate = "Latest Edit" case editDateReverse = "Oldest Edit" /// Returns a SortDescriptor matching the enumeration func sortDescriptor() -> SortDescriptor<T> { switch self { case .alphabetical: SortDescriptor<T>(\.name, comparator: .localized, order: .forward) case .alphabeticalReverse: SortDescriptor<T>(\.name, comparator: .localized, order: .reverse) case .createDate: SortDescriptor<T>(\.creationDate, order: .forward) case .createDateReverse: SortDescriptor<T>(\.creationDate, order: .reverse) case .editDate: SortDescriptor<T>(\.editDate, order: .forward) case .editDateReverse: SortDescriptor<T>(\.editDate, order: .reverse) } } } Which is used in struct ItemsList: View { @Environment(\.modelContext) private var modelContext @Query private var items:[Item] = [] init(sortStyle:ListSortingStyle<Item> = .alphabetical) { let sortDescriptor = SortDescriptor<Item>(\.name, comparator: .localized, order: .forward) //(1) This works in preview & simulator //OR let sortDescriptor2 = sortStyle.sortDescriptor() //(2) This crashes in a preview when used in a fetch not in the iOS simulator print(sortDescriptor,sortDescriptor2) let descriptor = FetchDescriptor<Item>(sortBy:[sortDescriptor2]) self._items = Query(descriptor) } var body: some View { ... } } As far as I can see both methods create a SortDiscriptor. If I print the sortDescriptor variable in they look almost identical: //1 SortDescriptor<Item>( order: Foundation.SortOrder.forward, keyString: nil, comparison: Foundation.SortDescriptor<MyApp.Item>.AllowedComparison.comparableString( (extension in Foundation):Swift.String.StandardComparator(options: __C.NSStringCompareOptions(rawValue: 0), isLocalized: true, order: Foundation.SortOrder.forward), \Item. <computed 0x0000000340213b18 (String)>) ) //2 SortDescriptor<Item>( order: Foundation.SortOrder.forward, keyString: nil, comparison: Foundation.SortDescriptor<MyApp.Item>.AllowedComparison.comparableString( (extension in Foundation):Swift.String.StandardComparator(options: __C.NSStringCompareOptions(rawValue: 0), isLocalized: true, order: Foundation.SortOrder.forward), \Item.<computed 0x0000000340022174 (String)>) ) But the one created with the generic method on the enum crashes with the error message: CrashReportError: Fatal Error in DataUtilities.swift MyApp crashed due to fatalError in DataUtilities.swift at line 64. Couldn't find \Item.<computed 0x0000000340022174 (String)> on Item with fields [SwiftData.Schema.PropertyMetadata ...
3
0
85
Apr ’25
XCODE Preview: XOJITError: Could not create code file directory for session: Permission denied
I keep running into the following issue when trying to run preview for my application in Xcode. FailedToLaunchAppError: Failed to launch app.a /Users/me/Library/Developer/Xcode/DerivedData/a-aloudjuytoewlldqjfxshbjydjeh/Build/Products/Debug/a.app ================================== | [Remote] JITError | | ================================== | | | [Remote] XOJITError | | | | XOJITError: Could not create code file directory for session: Permission denied`
3
0
112
Apr ’25
Xcode 16.3 Doesn't Remember Preview Pane Width
It seems like, by default, the preview pane tries to align to 50% of the editor pane's width. I prefer to shrink the preview pane to around ~30% of the screen so I have more space for code. This used to work fine—at least until I restarted Xcode. I never understood why the setting wouldn’t persist across sessions, but fine, that was a tradeoff I was willing to live with. However, with Xcode 16.3, it seems like Xcode forgets the manually adjusted preview pane width as soon as I switch to a different file. This has definitely impacted my productivity, as I now find myself readjusting the pane size dozens of times in a single session. Am I holding it wrong? Is anyone else experiencing this? And while we’re at it—why not make this a persistent setting so everyone can tweak the width to their liking?
10
8
303
Apr ’25
Latest version of Xcode has weird Preview issues
So I believe my machine JUST updated to Xcode 16.3 (16E140). But it definitely just installed the latest iOS simulator 18.4. However, now my preview will sometimes give me the error Failed to launch app ”Picker.app” in reasonable time. If I add a space in my code, or hit refresh on the Preview, then it will run on the second or third attempt. Sometimes in between the refreshes, the preview will crash, and then it will work again. Anyone else experiencing this? Any ideas? Thanks
1
1
137
Apr ’25
Crash in Preview (but not in Simulator) when using fileprivate on a protocol in Swift
Consider this stripped-down example of a view with a view model: import Observation import SwiftUI struct MainView: View { @State private var viewModel = ViewModel() private let items = [0, 1, 2] var body: some View { List { GroupedItemsView( viewModel : viewModel.groupState, groupedItems : [(0, items)] ) } } } fileprivate struct GroupedItemsView<ViewModel: GroupsExpandable>: View { let viewModel : ViewModel let groupedItems : [(ViewModel.GroupTag, [Int])] var body: some View { ForEach(groupedItems, id: \.0) { groupTag, items in Text("nothing") } } } fileprivate protocol GroupsExpandable: AnyObject { // HERE associatedtype GroupTag: Hashable } fileprivate final class GroupState<GroupTag: Hashable>: GroupsExpandable {} @Observable fileprivate final class ViewModel { var groupState = GroupState<Int>() } #Preview { MainView() } This compiles and runs fine in the Simulator, but it crashes in the Preview. However, when I remove the fileprivate modifier before GroupsExpandable (see HERE), it also runs in the Preview. What is the reason for this? Bug in Preview? Error on my side somewhere? Thanks. System is Xcode Version 16.3 (16E140) on a MacBook Pro 2018 (Intel) running Sequoia 15.3.2 Devices are iPhone 16 Pro Max with iOS 18.3.1, compiler is set to Swift 6.
1
0
89
Apr ’25
Previews stopped working in Xcode 16.3 with baffling error message
Upgrading to Xcode 16.3, all previews across my AppKit project stopped working. The error message I'm getting is especially baffling. It says the project could not be built with incremental compilation because SWIFT_COMPILATION_MODE is set to "incremental": I tried clearing DerivedData with no effect. When I click the diagnostics button the information given is not very revealing, at least not to me. If I open the project in Xcode 16.2 everything works perfectly again. I switched over to Previews for all new code but this error situation is quite demotivating. Does anyone have any suggestions?
1
2
221
Apr ’25
Setting UserDefaults in Preview
Hello, I've got a View that loads data from UserDefaults. I want to set the value of the UserDefault in the preview so i can see how it looks while developing. However when i am trying to set it in preview, i get the following error when i try set it in preview. 'buildExpression' is unavailable: this expression does not conform to 'View' What is the correct way to set the user defaults in preview? import Foundation class PreferencesViewModel: ObservableObject { @Published var maximumDistance: Double = UserDefaults.standard.value(for: .maximumDistance) as? Double ?? PreferencesViewModel.maximumDistanceOptions[0] { didSet { UserDefaults.standard.set(maximumDistance, for: .maximumDistance) } } #Preview { let preferencesViewModel = PreferencesViewModel() preferencesViewModel.maximumDistance = 5.0 PreferencesView() .environmentObject(PreferencesViewModel()) }
2
0
85
Apr ’25
Xcode Simulator Can't Boot
I am facing a recurring issue with Xcode iOS simulator. I want to preview a SwiftUI for iOS in Xcode, but the Simulator app fails to boot up. I receive the follow error in Xcode: Cannot Preview in this file. Simulator was shutdown during an update. I have tried the following: Deleting Xcode cache Reinstalling iOS Simulator runtimes Completely uninstalling Xcode and deleting all developer data, then reinstalling None of the above steps fix the problem. The only fix I have found is to completely reinstall MacOS 15.4.1. THIS IS TERRIBLE! I have already reinstalled MacOS 15.4.1 once to fix the issue, and I don't want to do it again. If there is another solution, please help me find it! Thank you!!
15
2
309
Aug ’25
SwitUI preview loads indefinitely
Hi! I develop an iOS library and I met an issue with SwiftUI previews in iOS app project with my library integrated. After I open preview, build for preview finishes successfully, but preview itself never appears. I failed to find any error messages or any other indicators of what went wrong or how to fix it. Switching to legacy preview execution seems to fix problem, but I think that is not ideal. Could you help fixing this? Xcode 16.2, Simulator iPhone 16, iOS 18.2 Project to reproduce - https://drive.google.com/file/d/1cU6JKwshK_wQfe9YIqcMg3UGWq45OYlx/view?usp=sharing Preview diagnostics - https://drive.google.com/file/d/1kPcgVSSqreiepGuqhdIoCW2rLSicgsWr/view?usp=sharing
7
0
188
May ’25
Previews globally fail with CouldNotLoadInputObjectFile error
Whenever I try to use SwiftUI previews, the preview fails with a CouldNotLoadInputObjectFile error like this: == PREVIEW UPDATE ERROR: FailedToLaunchAppError: Failed to launch com.my-company.Test | ================================== | | [Remote] CouldNotLoadInputObjectFile: Could not load object file during preview: /Users/me/Library/Developer/Xcode/DerivedData/Test-dzmdthicvcbuwkawncuacsomcdcd/Build/Intermediates.noindex/Test.build/Debug-iphonesimulator/Test.build/Objects-normal/arm64/TestApp.o | | | | path: /Users/me/Library/Developer/Xcode/DerivedData/Test-dzmdthicvcbuwkawncuacsomcdcd/Build/Intermediates.noindex/Test.build/Debug-iphonesimulator/Test.build/Objects-normal/arm64/TestApp.o | | | | ================================== | | | [Remote] XOJITError | | | | | | XOJITError: '/Users/me/Library/Developer/Xcode/DerivedData/Test-dzmdthicvcbuwkawncuacsomcdcd/Build/Intermediates.noindex/Test.build/Debug-iphonesimulator/Test.build/Objects-normal/arm64/TestApp.o': No such file or directory It appears that the preview process cannot find the compiled .o files. However, when I check in Finder, the files do exist and normally running the app works fine. It is noteworthy that this is independent of the XCode project or view I try to preview. It is a global issue on my system. Previews not even work when I create a blank new SwiftUI project in XCode. I tried deleting all caches, derived data, preview caches etc. But without any effect. I have this in XCode 16.3 as well as in 16.4 RC. On macOS Sequoia 15.4.1 on a MacBook Air M4. Does anybody have an idea what might be causing this?
3
2
118
Aug ’25
Canvas keeps resizing to 50/50 width in Xcode
Hello, Xcode seems to reset the canvas preview every time I open a file that does not have a preview. This is extremely annoying when working with two editor tabs. The resize happened before only after restarting Xcode since a few weeks it happens always when opening another file. The preview phone does not even take advantage of the resize. Is there a way to fix this? When I work with the file: After opening a file without preview and going back:
1
0
107
May ’25
Xcode Resets the Canvas (Preview) Window
Hello, In the recent update i installed of Mac and Xcode. After working out the initial problem of Simulator runtimes not found, I created a new project with new problem where When i switch to a different file, or Hide and Show Canvas again it just resets to its size (approx. 50%) of Editor. The current solution is to Pin it and it stays there with right size (No matter which file - with any extension - to switch from or to then). I tried deleting Derived Data folder, Rebooting Mac, Reintsalled Xcode (When Simulator Runtime not found problem) but the problem is there. I also tried trait property but fixedLayout do not work with iOS.
1
0
90
May ’25
Why is Xcode so slow and bad?
I just want to rant why is Xcode such a bad ide and I wish Apple can do a better job on Xcode. Here's why: The preview is so slow. Most of the times it's just faster for me to test on a real device. It is so slow, and many times I need to force quite after it's being unresponsive for sometimes. When I'm working on larger projects, the loading time becomes extremely slow especially when there's other clients that might be reading the same files like a Git client or simply iCloud. The breakpoint is so slow. I don't know why, is it an iOS thing? But when I'm on ASP.Net the breakpoints are super fast. For Xcode it takes a long time to pause and show data. It's so big I don't know why it is so hard for Apple to make their ide better. The community has been unsatisfied with Xcode for a long time. There's many tricks on the internet that you can find to help you resolve some issues with your project that's actually related to Xcode. Instead of using these tricks, Apple should just fix these issues. Learn from Intellij!
1
3
209
May ’25