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@Observable is being re-init every time view is modified
I am surprised at what I am seeing with the new @Observable framework in iOS 17. It seems that if the view containing the @State var, ie viewModel, is modified, then the init of that viewModel will also be called. This is not the behavior of the prior StateObject method of using a viewModel. As I understand the @State should not be reinitialized on redrawing on the View, is this the expected behavior? Example: struct ContentView: View { @State var offset = false var body: some View { VStack { InnerView() .offset(x: offset ? 200 : 0) Button("Offset") { offset.toggle() } } } } // iOS 17 Observable method: struct InnerView: View { @State var viewModel: ViewModel init() { self._viewModel = State(wrappedValue: ViewModel()) } var body: some View { VStack { Image(systemName: "globe") .imageScale(.large) .foregroundStyle(.tint) Text("Hello, world!") } .padding() } } @Observable class ViewModel { init() { print("ViewModel Init") } } // StateObject method: struct InnerView: View { @StateObject var viewModel: ViewModel init() { self._viewModel = StateObject(wrappedValue: ViewModel()) } var body: some View { VStack { Image(systemName: "globe") .imageScale(.large) .foregroundStyle(.tint) Text("Hello, world!") } .padding() } } class ViewModel: ObservableObject { init() { print("ViewModel Init") } }
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Oct ’23