Pinned
WWDC26 brought the new @State macro to succeed the property wrapper, but what’s different about the macro, and how does it work? We’ll pick apart the cryptic macro expansions to see something quite simple at its core.
pointfree.co/episodes/ep378…
![Code from Apple's SampleTrips WWDC26 project (with problem areas highlighted):
struct TripMap: View {
@Environment(\.modelContext) private var modelContext
@Binding var selection: Trip?
@State private var mapController: MapCameraController?
@State private var mapSelection: MapSelection<Trip>?
init(selection: Binding<Trip?>) {
self._selection = selection
}
private var cameraPosition: Binding<MapCameraPosition> {
Binding(
get: { mapController?.cameraPosition ?? .automatic },
set: { mapController?.cameraPosition = $0 }
)
}
var body: some View {
Map(position: cameraPosition, selection: $mapSelection) {
ForEach(mapController?.trips ?? []) { (trip: Trip) in
if let location = trip.location {
Marker(trip.name, coordinate: location.coordinate)
.tint(trip.color)
.tag(MapSelection(trip))
}
}
}
.onAppear {
self.mapController = MapCameraController(modelContext: modelContext)](https://pbs.twimg.com/media/HROqQihbkAAe9jx?format=webp&name=small)
![Code from Apple's SampleTrips WWDC26 project (with problem areas highlighted):
struct TripMap: View {
@Environment(\.modelContext) private var modelContext
@Binding var selection: Trip?
@State private var mapController: MapCameraController?
@State private var mapSelection: MapSelection<Trip>?
init(selection: Binding<Trip?>) {
self._selection = selection
}
private var cameraPosition: Binding<MapCameraPosition> {
Binding(
get: { mapController?.cameraPosition ?? .automatic },
set: { mapController?.cameraPosition = $0 }
)
}
var body: some View {
Map(position: cameraPosition, selection: $mapSelection) {
ForEach(mapController?.trips ?? []) { (trip: Trip) in
if let location = trip.location {
Marker(trip.name, coordinate: location.coordinate)
.tint(trip.color)
.tag(MapSelection(trip))
}
}
}
.onAppear {
self.mapController = MapCameraController(modelContext: modelContext)](https://pbs.twimg.com/media/HROqQihbkAAe9jx?format=webp&name=medium)
