I’m trying to show the camera tracking state info on top of device screen, but still get errors for all my efforts. I’m very confused with how ARView works with SwiftUI, for showing AR experience and adding button icons on top of it is simple, but to getting data from session just looks more work need to be done, could someone help me this? Thanks! Error in ViewModel: ‘description is a get-only property’
ContentView
import SwiftUI
import ARKit
import RealityKit
struct ContentView: View {
@StateObject var vm = ViewModel()
var body: some View {
ZStack{
ARViewContainer()
.edgesIgnoringSafeArea(.all)
.environmentObject(vm)
VStack{
Text(vm.sessionInfoLabel)
.font(.title3)
.foregroundColor(.red)
Spacer()
HStack{
Button{
} label: {
Image(systemName: "person.2")
.padding()
.font(.title)
}
Spacer()
Button{
} label: {
Image(systemName: "target")
.padding()
.font(.title)
}
}
.padding()
}
}
}
}
struct ARViewContainer: UIViewRepresentable {
@EnvironmentObject var vm: ViewModel
func makeUIView(context: Context) -> ARView {
return vm.arView
}
func updateUIView(_ uiView: ARView, context: Context) {
}
}
ViewModel
import SwiftUI
import ARKit
import RealityKit
class ViewModel: ObservableObject {
@Published var arView: ARView
var sessionInfoLabel = ""
init() {
arView = ARView.init(frame: .zero)
let config = ARWorldTrackingConfiguration()
config.planeDetection = .horizontal
arView.session.delegate = arView
arView.session.run(config)
}
}
extension ARView: ARSessionDelegate {
public func session(_ session: ARSession, cameraDidChangeTrackingState camera: ARCamera) {
camera.trackingState.description = ViewModel().sessionInfoLabel
}
}
extension ARCamera.TrackingState: CustomStringConvertible {
public var description: String {
switch self {
case .normal:
return "Normal"
case .notAvailable:
return "Not Available"
case .limited(.initializing):
return "Initializing"
case .limited(.excessiveMotion):
return "Excessive Motion"
case .limited(.insufficientFeatures):
return "Insufficient Features"
case .limited(.relocalizing):
return "Relocalizing"
case .limited:
return "Unspecified Reason"
}
}
}
Hello Franklan010,
There are a few issues in the code you posted. For one, the compiler error you are receiving is because you are trying to set camera.trackingState.description, but you have defined description as a get-only property.
In any case, I have put together a short snippet that more or less demonstrates the basics of how you can integrate an ARView with SwiftUI, and utilize ARSession state to update your views (in this case, a Text view):
struct ContentView: View {
@State var viewModel = ARViewContainer.ViewModel()
var body: some View {
ZStack {
ARViewContainer(viewModel: $viewModel).ignoresSafeArea()
Text(viewModel.trackingState?.description ?? "")
.font(.headline)
.foregroundColor(.green)
}
}
}
struct ARViewContainer: UIViewRepresentable {
struct ViewModel {
var trackingState: ARCamera.TrackingState? = nil
}
@Binding var viewModel: ViewModel
func makeUIView(context: Context) -> ARView {
// Create the view.
let view = ARView(frame: .zero)
// Set the coordinator as the session delegate.
view.session.delegate = context.coordinator
// Return the view.
return view
}
func updateUIView(_ uiView: ARView, context: Context) {}
func makeCoordinator() -> Coordinator {
Coordinator(self)
}
final class Coordinator: NSObject, ARSessionDelegate {
var parent: ARViewContainer
init(_ parent: ARViewContainer) {
self.parent = parent
}
func session(_ session: ARSession, cameraDidChangeTrackingState camera: ARCamera) {
parent.viewModel.trackingState = camera.trackingState
}
}
}
