NavigationSplitView & CoreData Generating an error when adding first entity

Question

antokne OP

Created May ’23

Replies 1

Boosts 0

Participants 2

Hi,

I am using a NSOutlineView with a simple @FetchRequest containing content: and detail: sections. e.g.

    NavigationSplitView {
			List(tags, selection: $selectedTag) { tag in
				NavigationLink(value: tag) {
						Text(tag.name ?? "")
				}
			}
		} content: {
			if let selectedTag {
				let fetchRequest = FetchRequest(fetchRequest: Location.sortedFetchRequest(tag: selectedTag))
				AGLocationListView(locations: fetchRequest)
			}
			else {
				Text("Select a Tag")
			}
		} detail: {
			if let selectedTag {
				AGMapView(viewModel: AGMapViewModel(tag: selectedTag))
			}
		}
	}

I am inserting a new record using the viewContext on the main thread. in the case when there are no records in the Tag entity I sometimes see the following error:

2023-05-11 22:49:36.388105+1200 Taggy[24576:1000186] [General] NSOutlineView error inserting child indexes &lt;_NSConstantIndexSet: 0x7ff857d84860>[number of indexes: 1 (in 1 ranges), indexes: (1)] in parent 0x0 (which has 0 children).

Then a large stack trace topmost line being:

	2   AppKit                              0x00007ff818343b6b -[NSOutlineView _validateParentRowEntry:reason:indexes:] + 0

then see:

NSHostingView is being laid out reentrantly while rendering its SwiftUI content. This is not supported and the current layout pass will be skipped.
2023-05-11 22:49:38.376608+1200 Taggy[24576:1000186] [SwiftUI] Publishing changes from within view updates is not allowed, this will cause undefined behavior.

Not sure what I am doing wrong here or if this is an issue with SwiftUI on the Mac with the Split View?

Thanks Ants

Boost

Answer 1

szymczyk OP

May ’23

Show the code where you add the entity.

If you want to see whether the issue is with the split view, create a list that just shows the items and add a way to add new items. If you still have problems, you know the split view isn't causing the problems.

Also see the following Stack Overflow question:

https://stackoverflow.com/questions/73028881/swiftui-list-crashes-when-adding-items-on-macos

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