I am trying to get my head around how to implement a MapKit view using UIViewRepresentable (I want the map to rotate to align with heading, which Map() can't handle yet to my knowledge). I am also playing with making my LocationManager an Actor and setting up a listener. But when combined with UIViewRepresentable this seems to create a rather convoluted data flow since the @State var of the vm needs to then be passed and bound in the UIViewRepresentable. And the listener having this for await location in await lm.$lastLocation.values seems at least like a code smell. That double await just feels wrong. But I am also new to Swift so perhaps what I have here actually is a good approach?
struct MapScreen: View {
@State private var vm = ViewModel()
var body: some View {
VStack {
MapView(vm: $vm)
}
.task {
vm.startWalk()
}
}
}
extension MapScreen {
@Observable
final class ViewModel {
private var lm = LocationManager()
private var listenerTask: Task<Void, Never>?
var course: Double = 0.0
var location: CLLocation?
func startWalk() {
Task {
await lm.startLocationUpdates()
}
listenerTask = Task {
for await location in await lm.$lastLocation.values {
await MainActor.run {
if let location {
withAnimation {
self.location = location
self.course = location.course
}
}
}
}
}
Logger.map.info("started Walk")
}
}
struct MapView: UIViewRepresentable {
@Binding var vm: ViewModel
func makeCoordinator() -> Coordinator {
Coordinator(parent: self)
}
func makeUIView(context: Context) -> MKMapView {
let view = MKMapView()
view.delegate = context.coordinator
view.preferredConfiguration = MKHybridMapConfiguration()
return view
}
func updateUIView(_ view: MKMapView, context: Context) {
context.coordinator.parent = self
if let coordinate = vm.location?.coordinate {
if view.centerCoordinate != coordinate {
view.centerCoordinate = coordinate
}
}
}
}
class Coordinator: NSObject, MKMapViewDelegate {
var parent: MapView
init(parent: MapView) {
self.parent = parent
}
}
}
actor LocationManager{
private let clManager = CLLocationManager()
private(set) var isAuthorized: Bool = false
private var backgroundActivity: CLBackgroundActivitySession?
private var updateTask: Task<Void, Never>?
@Published var lastLocation: CLLocation?
func startLocationUpdates() {
updateTask = Task {
do {
backgroundActivity = CLBackgroundActivitySession()
let updates = CLLocationUpdate.liveUpdates()
for try await update in updates {
if let location = update.location {
lastLocation = location
}
}
} catch {
Logger.location.error("\(error.localizedDescription)")
}
}
}
func stopLocationUpdates() {
updateTask?.cancel()
updateTask = nil
}
func locationManagerDidChangeAuthorization(_ manager: CLLocationManager) {
switch clManager.authorizationStatus {
case .authorizedAlways, .authorizedWhenInUse:
isAuthorized = true
// clManager.requestLocation() // ??
case .notDetermined:
isAuthorized = false
clManager.requestWhenInUseAuthorization()
case .denied:
isAuthorized = false
Logger.location.error("Access Denied")
case .restricted:
Logger.location.error("Access Restricted")
@unknown default:
let statusString = clManager.authorizationStatus.rawValue
Logger.location.warning("Unknown Access status not handled: \(statusString)")
}
}
func locationManager(_ manager: CLLocationManager, didFailWithError error: Error) {
Logger.location.error("\(error.localizedDescription)")
}
}
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