iOS .onContinueUserActivity Not Being Called

Question

.onContinueUserActivity is never called in the state restoration example app provided by Apple.

Inside of DetailView, this method is called:

// The described activity for this view.
.userActivity(DetailView.productUserActivityType,
              isActive: product.id.uuidString == selectedProductID) { userActivity in
    describeUserActivity(userActivity)
}

Inside of ContentView (parent of DetailView), this method is NOT called:

.onContinueUserActivity(DetailView.productUserActivityType) { userActivity in
    if let product = try? userActivity.typedPayload(Product.self) {
        selectedProduct = product.id.uuidString
    }
}

I know .onContinueUserActivity is not being called by placing print statements in the method, and because commenting it out has no effect on the app's restoration.

The "Test State Restoration" strategies listed here do not work.

Answer 1

Just to note that this works on the Mac, so it is just a bug in iOS implementation, I think from iOS 16 onwards.

Answer 2

I think this might be a case of sample code that doesn't work the way it's advertised. If you correctly test the app that's built from the sample code, it does restore state of the app, but not through the mechanism that they claim to be using.

You are correct. The onContinueUserActivity block isn't being called at all. You can remove that code from the app, and it continues to restore state in the way the NSUserActivity mechanism is supposed to. Further testing shows that it's just this line that's achieving the restoration:

@SceneStorage("ContentView.selectedProduct") private var selectedProduct: String?

That's a shame. I hope this gets sorted out soon.