[blacktriangle]

Take a look at NSFetchedResultsController, it gives you what you want from NSObjectController and NSArrayController, and there aren't really UI widgets on iOS where NSTreeController is appropriate like there are in AppKit.

[andrekandre]

there might not be any native uis in uikit that need nstreecontroller, but ive done custom uis in appkit that utilized nstreecontroller (think of a diagramming ui with groups and child groups) and would love to have been able to use those in uikit too, with pure data bindings....

[ericlewis]

There are now, DisclosureGroups & OutlineGroup especially would be places in SwiftUI where a NSTreeController might be useful.