Hi !

I have 3 core data objects in which get pulled into a view to populate with data. I would like the user to edit one of the core data objects however, I cant seem to select which object it is. Do I have to run a for loop to cycle through and provide some if statements? Or should use some sort of fetch filter?

Hello,

You could loop through the @FetchedResults and implement methods of editing each object of the loop individually. I think this is the easiest way. You could pass the elements of the loop to a new view, and use an @ObservedObject wrapper in the new view. On the new view in which you passed the element from the loop, you could implement changes and also mark the passed Core Data entity with a .objectWillChange.send() method:

                    observedElement.objectWillChange.send()

You would call the .objectWillChange.send() inside the function in which you change the managed object context to reflect the changes (like the button that saves the data):

The child view:

                @Environment(\.managedObjectContext) var moc
                @Environment(\.dismiss) var dismiss
                @ObservedObject var observedElement: ElementType

Note: I called it ElementType as an example, it is your Core Data element, how you chose to call it)

Then, in the body:

                Button {
                    observedElement.objectWillChange.send()
                    observedElement.anAttribute = newAttribute

                  if moc.hasChanges {
                        do {
                            try moc.save()
                        } catch {
                            print(error)
                        }
                    }
                    dismiss()

To retrieve a particular instance of a core data entity, you would either use an NSPredicate with some particular filtering, or you would have to implement an ID for each element and a function that retrieves that very element based on the specific ID.

For simple applications, I'd avoid this last method of retrieving data by ID.

Hope it helps!