Hi everyone,
I believe this should be a simple and expected default behavior in a real-world app, but I’m unable to make it work: 1. I have a View (a screen/page in this case) that calls an endpoint using async/await. 2. If the endpoint hasn’t finished, but I navigate forward to a DetailView, I want the endpoint to continue fetching data (i.e., inside the @StateObject ViewModel that the View owns). This way, when I go back, the View will have refreshed with the fetched data once it completes. 3. If the endpoint hasn’t finished and I navigate back to the previous screen, I want it to be canceled, and the @StateObject ViewModel should be deinitialized.
I can achieve 1 and 3 using the .task modifier, since it automatically cancels the asynchronous task when the view disappears:
view
.task { await vm.getData() }
I can achieve 1 and 2 using a structured Task in the View (or in the ViewModel, its the same behavior), for example:
.onFirstAppearOnly {
Task { away vm.getData() }
}
onFirstAppearOnly is a custom modifier that I have for calling onAppear only once in view lifecycle. Just to clarify, dont think that part is important for the purpose of the example
But the question is: How can I achieve all three behaviors? Is this really such an unusual requirement?
My minimum deployment target is iOS 15, and I’m using NavigationView + NavigationLink. However, I have also tried using NavigationStack + NavigationPath and still couldn’t get it to work.
Any help would be much appreciated. Thank you, folks!