在独立watchOS应用上实施核心数据

Question

据我所知，我们可以在Apple Watch应用程序上使用核心数据。因此，独立的watchOS应用程序可以拥有自己的持久存储。但是，当我们为watchOS应用创建项目时，就没有使用核心数据的选项（例如，当我们为iOS应用创建项目时）

那么，如何在独立的watchOS应用上实现核心数据？

我已从iOS应用程序（使用Core Data）复制了此代码，并将其粘贴到我的独立SwiftUI watchOS应用程序的ExtensionDelegate中

 // MARK: - Core Data stack

    lazy var persistentContainer: NSPersistentContainer = {
        /*
         The persistent container for the application. This implementation
         creates and returns a container, having loaded the store for the
         application to it. This property is optional since there are legitimate
         error conditions that could cause the creation of the store to fail.
        */
        let container = NSPersistentContainer(name: "CoreDataToDo")
        container.loadPersistentStores(completionHandler: { (storeDescription, error) in
            if let error = error as NSError? {
                // Replace this implementation with code to handle the error appropriately.
                // fatalError() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.

                /*
                 Typical reasons for an error here include:
                 * The parent directory does not exist, cannot be created, or disallows writing.
                 * The persistent store is not accessible, due to permissions or data protection when the device is locked.
                 * The device is out of space.
                 * The store could not be migrated to the current model version.
                 Check the error message to determine what the actual problem was.
                 */
                fatalError("Unresolved error \(error), \(error.userInfo)")
            }
        })
        return container
    }()

    // MARK: - Core Data Saving support

    func saveContext () {
        let context = persistentContainer.viewContext
        if context.hasChanges {
            do {
                try context.save()
            } catch {
                // Replace this implementation with code to handle the error appropriately.
                // fatalError() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
                let nserror = error as NSError
                fatalError("Unresolved error \(nserror), \(nserror.userInfo)")
            }
        }
    }

所以接下来我该怎么办？还是我已经做错了？

请帮助我。我已经非常努力地寻找如何做到这一点。但是我找不到任何好的解决方案，因为以前没有独立的watchOS应用程序，因此大多数开发人员没有为watchOS应用程序创建单独的持久存储。所以请帮帮我。谢谢。

Answer 1

您还需要确保您也有一个xcdatamodeld文件，然后您应该会很好。请参阅我对this question的回答，以了解如何将托管对象上下文传递给View以及如何正确设置WKHostingController子类。