SwiftUI Preview canvas and Core Data

Question

Preview canvas is is crashing but in simulator everything working fine. I assuming it related to @ObservedObject and @Fetchrequest...

tried solution for here Preview

Answer 1

Works for SwiftUI 2 app using the App template

I also had the previews crash and none of the other solutions were suitable or worked for me.

What I did was rather than the following:

struct ContentView_Previews: PreviewProvider {
  
    static var previews: some View {
        return ContentView()
            .environment(
                \.managedObjectContext,
                CoreDataManager.context
            )
    }
}

I fixed it with:

struct ContentView_Previews: PreviewProvider {
    
    static var previews: some View {
        let context = CoreDataManager.context

        /* Optional sample data can be inserted here */
        
        return ContentView()
            .environment(
                \.managedObjectContext,
                context
            )
    }
}

Where CoreDataManager is:

enum CoreDataManager {
    
    static var context: NSManagedObjectContext {
        persistentContainer.viewContext
    }
    
    static let persistentContainer: NSPersistentContainer = {
        let container = NSPersistentContainer(name: "MyContainerName")
        
        container.loadPersistentStores { description, error in
            guard let error = error else { return }
            fatalError("Core Data error: '\(error.localizedDescription)'.")
        }
        
        return container
    }()
}

Not exactly sure why this helped, but now it works perfectly. Additionally you can add sample data to this context where I have marked with a comment.