SwiftUI, Core Data/SwiftData and Tight Coupling with the Views

Question

I am starting to work on Core Data applications with SwiftUI. I have a view that looks like this:

struct ContentView: View {
 @FetchRequest(sortDescriptors: []) private var todoItems: FetchedResults<TodoItem>
 enter code here
 var body: some View {
 List(todoItems) { todoItem in
 Text(todoItem.title)
 }
 }
}

This works and I can display all the todo items on the screen. But now my view is tightly coupled with Core Data. What if in the future, the client decides that they want to use Realm or GRDB?

Should I separate out my data access layer completely?

But if I do that then I would not be able to use all the property wrappers for Core Data that are available for SwiftUI like @FetchRequest and @SectionedFetchedRequest.

How would you handle such situation?

Answer 1

Not only does your view depend on the data layer, but the data layer also depends on the view.

The simplest method to separate it properly is MVC or model-view-controller: You have a model class which gathers your data, by any means it likes. You have your view class which displays data, wherever it comes from. And you have a controller class, which asks the model what data is there, tells the view what to display, gets told by the view what actions to take and passes that to the model.

The model doesn’t even know there is a view. The view doesn’t even know there is a model. The controller has interfaces for model and view but has no idea how they do their job.

• john doe: Thanks! Do you recommend MVC to be used for SwiftUI framework?