Swift 5.7 SwiftUI Documentation

Manuel · November 19, 2022, 5:12pm

I think the question is more related to how to code with SwiftUI. I guess a basic SwiftUI tutorial should give you a good place to start.

I have seen some code examples in this issue, maybe that helps:

github.com/parse-community/Parse-SDK-iOS-OSX

Creating objects with init(withoutDataWithObjectId:) causes crash in SwiftUI preview

opened 12:51PM - 28 Oct 22 UTC

drbarto

type:bug bounty:$20

### New Issue Checklist - [x] I am not disclosing a [vulnerability](https://g…ithub.com/parse-community/Parse-SDK-iOS-OSX/security/policy). - [x] I am not just asking a [question](https://github.com/parse-community/.github/blob/main/SUPPORT.md). - [x] I have searched through [existing issues](https://github.com/parse-community/Parse-SDK-iOS-OSX/issues?q=is%3Aissue). - [x] I can reproduce the issue with the latest versions of [Parse Server](https://github.com/parse-community/parse-server/releases) and the [Parse ObjC SDK](https://github.com/parse-community/Parse-SDK-iOS-OSX/releases). ### Issue Description In a Swift project using the Parse pod, I create a bunch of dummy objects using `init(withoutDataWithObjectId:)` for use in tests and SwiftUI previews. When running the app or unit tests, these objects can be created without problem; however, when trying to create them in the context of a SwiftUI preview, the process crashes. ### Steps to reproduce To give an example, e.g. I have classes `User` and `Project` defined as follows: ```swift class User: PFUser { @NSManaged var firstName: String? @NSManaged var lastName: String? } class Project: PFObject, PFSubclassing { class func parseClassName() -> String { "Project" } @NSManaged var name: String? } ``` Sample code for creating dummy objects: ```swift let user = User(withoutDataWithObjectId: "user_1") user.firstName = "..." user.lastName = "..." user.email = "[email protected]" let project = Project(withoutDataWithObjectId: "project_1") project.name = "..." ``` Finally I want to provide the dummy objects to my UI code, so that it can be tested and previewed without a server connection: ```swift struct UsersView_Previews: PreviewProvider { static var previews: some View { SomeFancyView(user: user, project: project) } } ``` ### Actual Outcome Executing the above "dummy object creation" code works fine when running the app or the unit tests. However, when executing it in the context of the Xcode SwiftUI preview window, it crashes with these errors: When executing `User(withoutDataWithObjectId: "user_1")`: > MyApp crashed due to an uncaught exception `NSInvalidArgumentException`. > Reason: Invalid class name. Class names cannot start with an underscore. When executing `project.name = "..."`: > MyApp crashed due to an uncaught exception `NSInvalidArgumentException`. > Reason: -[PFObject setName:]: unrecognized selector sent to instance 0x600001c74480. I can avoid the 2nd issue with `setName` by replacing the call with `project.setValue("...", forKey: "name")`. However, I found no workaround for the 1st crash related to the classname. ### Expected Outcome The dummy objects can be created without crashing the process. ### Environment Client - Parse ObjC SDK version 1.19.4 (Cocoapods / Xcode 13.4.1) Server - does not apply Database - does not apply ### Logs none