Nsmanagedobject Changes Do Not Trigger Objectwillchange

NSManagedObject relationship changes handling

All CoreData objects are ObservableObjects if you want to see changes you have to wrap them in a @ObservedObject.

To do this make subviews that take profile, wallet, and balance as a parameter vs having all those variables with your subviews.

Why does @Published not work in NSManagedObject?

The solution is to add a transient Core Data attribute. Transient attributes are published but not persisted.

Alternatively, you can publish changes like this:

class Data2: NSManagedObject {
    @Published var direction: Direction = .left { // @Published is optional
        willSet {
            objectWillChange.send()
        }
    }
}

SwiftUI: trigger redraw when NSManagedObject (not part of fetch request) bool property changes?

Move it all into a sub-View and use @ObservedObject like this:

struct DealerSection : View {
    @ObservedObject var dealer: Dealer // body will be called when dealer changes.

    var body: some View {
        Section(header:  DealerSHView(dealer: dealer)) {

            if dealer.isOpen {
                 ForEach(section) { channel in
                     ....
                 }
            } else {
                 ....
            }

         }
    }

Then in your parent View's body it's just:

ForEach(carsResult) { section in
                        
        if let dealer = section.first?.dealer {
                            
            DealerSection(dealer: dealer)
                            
        }
                        
    }

SwiftUI update view on core data object change

Try to observe Asset (cause NSManagedObject is-a ObservableObject)

struct AssetRowView: View {
    @ObservedObject var asset: Asset        // << here !!
    
    var body: some View {
        HStack {
           Text(asset.name)
           Text(asset.assetDescription)
        }
    }
}

if that will not be enough, also might be needed to update Done button action as

}, trailing: Button("Done") {
    self.asset.objectWillChange.send()             // << here !!
    self.asset.name = self.name
    self.asset.assetDescription = self.description
    try? self.moc.save()

    // better do this at the end of activity
    self.presentationMode.wrappedValue.dismiss()
}

Core data not triggering immediate refresh with SwiftUI

I used the approach suggested by jnpdx and it works.

import SwiftUI

class PointsViewModel: ObservableObject {
    @Published var points = [Point]()
    
    func movePoint(index: Int, x: CGFloat, y: CGFloat) {
        points[index].x = x
        points[index].y = y
        objectWillChange.send()
    }
}

struct RedrawEdgeTestCoreData: View {
    
    @Environment(\.managedObjectContext) private var viewContext
    
    @ObservedObject var viewModel: PointsViewModel
    @State var originalPosition: CGPoint? = nil
    
    private var movePointDragGesture: some Gesture {
        DragGesture(minimumDistance: 0, coordinateSpace: .local)
            .onChanged { value in
                if viewModel.points.isEmpty {
                    return
                }
                
                if originalPosition == nil {
                    originalPosition = CGPoint(x: viewModel.points.last!.x, y: viewModel.points.last!.y)
                }
                
                let lastIndex = viewModel.points.count - 1
                viewModel.movePoint(index: lastIndex, x: originalPosition!.x + value.translation.width, y: originalPosition!.y + value.translation.height)
            }
            .onEnded { value in
                originalPosition = nil
            }
    }
    
    private var addNewPointGesture: some Gesture {
        TapGesture(count: 2)
            .onEnded {
                viewModel.points.append(Point(context: viewContext))
            }
    }
    
    var body: some View {
        GeometryReader { geometry in
            ZStack {
                ShapeTest(points: viewModel.points.map { CGPoint(x: $0.x, y: $0.y) })
                    .stroke()
            }
            .contentShape(Rectangle())
            .gesture(movePointDragGesture.simultaneously(with: addNewPointGesture))
        }
    }
}

struct RedrawEdgeTestCoreData_Previews: PreviewProvider {
    static var previews: some View {
        RedrawEdgeTestCoreData(viewModel: PointsViewModel())
            .environment(\.managedObjectContext, PersistenceController.preview.container.viewContext)
    }
}

FetchedResults won't trigger and SwiftUI update but the context saves it successfully

If first code block is a part of ObservableObject, then it does not look that third block, view one, depends on it, and if there is no changes in dependencies, view is not updated.

Try this approach.

But if there are dependencies, which are just not provided then change order of save and publisher as

try context.save()
self.objectWillChange.send()

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