Skip to content
Here Be Dragons

UIKit navigation, tabs, split views, and coordinators

UIKit container controllers own navigation structure. A coordinator becomes useful when several screens or entry points need one route policy.

Route by intent

enum Route {
    case note(NoteID)
    case settings
}


@MainActor
final class NotesCoordinator {
    private let navigationController: UINavigationController
    private let library: NoteLibrary


    func open(_ route: Route) {
        switch route {
        case .note(let id):
            navigationController.pushViewController(
                NoteDetailViewController(noteID: id, library: library),
                animated: true
            )
        case .settings:
            navigationController.pushViewController(SettingsViewController(), animated: true)
        }
    }
}

Rows emit open(.note(id)). They do not search globally for a visible controller. The coordinator owns UIKit mechanics while the route remains framework-neutral.

Adapt one selection model

On a compact phone, selecting a note pushes detail. In a regular split view, the same selection replaces the secondary column. Collapse and expansion reconcile current selection instead of inventing a second navigation truth.

Tabs represent a few peer destinations with durable meaning. They are not a storage place for every feature. Each tab commonly owns its own navigation stack so switching tabs does not discard local history.

Parse external input into a route, validate the note against current data, then ask the active scene coordinator to present it. Restoration uses stable IDs and drops invalid destinations without crashing.

Do not add a coordinator for one trivial modal. Add it when navigation spans screens, adapts across containers, or serves deep links and restoration.

Validation boundary

The examples were not compiled. Push and pop behavior, split collapse, tab state, coordinator ownership, deep links, and restoration remain Not verified.

Series navigation

References

Why the name "Here Be Dragons"?