Without having to use @FetchRequest at the View level has any been able to successfully implement a CoreData Stack with observability in a model with the model being used at the View level. The view model sits between the View & Coredata Stack
CoreData Stack
ViewModel (ObservableObject)
SwiftUI View
hi,
your ViewModel simply needs to use an NSFetchedResultsController to hook into Core Data, and keep the array of Core Data objects that you would ordinarily define in the View (using @FetchRequest) as a @Published property. whenever the resultsController fires, update the array property.
be sure your View keeps a reference to the ViewModel as an @ObservedObject.
hope that helps,
DMG
Thanks, did as you suggested but no joy. Even tried a few references on the web using passthrough subjects. The FRC does load the objects on perform fetch but the FRCDelegates isn't invoked when the context changes. So I might have to abstract the @FetchRequest into utility views away from the main set of views.
--
hi,
your ViewModel simply needs to use an NSFetchedResultsController to hook into Core Data, and keep the array of Core Data objects that you would ordinarily define in the View (using @FetchRequest) as a @Published property. whenever the resultsController fires, update the array property.
be sure your View keeps a reference to the ViewModel as an @ObservedObject.
hope that helps,
DMG
Thanks, did as you suggested but no joy. Even tried a few references on the web using passthrough subjects. The FRC does load the objects on perform fetch but the FRCDelegates isn't invoked when the context changes. So I might have to abstract the @FetchRequest into utility views away from the main set of views.
--
@DelawareMathGuy this is what I had to do to trigger the FRCDelegate but this goes against the FRC automatically doing it after the performFetch
fetchedResultsController?
.publisher(for: \.fetchedObjects)
.receive(on: OperationQueue.main)
.sink(receiveValue: { [weak self] data in
guard let self = self,
let data = data else { return }
for (index, object) in data.enumerated() {
let indexpath = IndexPath(item: index, section: 0)
if let controller = self.fetchedResultsController as? NSFetchedResultsController<NSFetchRequestResult> {
self.controller(controller, didChange: object,
at: nil,
for: .insert,
newIndexPath: indexpath)
}
}
}).store(in: &cancellables)
Hmm, I found the problem ...