Infinite loop refreshing view with EnvironmentValue

Question

Created Apr ’24

Replies 2

Boosts 6

Participants 3

Adding environment value openURL or dismiss to a View in a NavigationStack, without even using it, causes an infinite refresh loop.

What doesn't work:

a)

struct ViewA: View {
    @State private var path = NavigationPath()
    
    var body: some View {
        NavigationStack(path: $path) {
            ViewB()
        }
    }
}

struct ViewB: View {
    @Environment(\.openURL) var openURL
    
    var body: some View {
        NavigationLink("Next", value: 1)
            .navigationDestination(for: Int.self, destination: itemView)
    }
    
    func itemView(_ item: Int) -> some View {
        Text("Item \(item)")
    }
}

Prints ViewB: _openURL changed. infinitely.

b) Passing the path to ViewB and appending the value with a Button

What works:

a)

.navigationDestination(for: Int.self) {
    Text("Item \($0)")
}

Prints

ViewB: @self, @identity, _openURL changed.
ViewB: @self, _openURL changed.
ViewB: _openURL changed. (3 times)

b) Handling the destination on ViewA, which is not ideal for my use case.

Prints

ViewB: @self, @identity, _openURL changed.
ViewB: _openURL changed. (5 times)

While the workaround would work, it is still unclear how the environment value can cause the freeze (and eventual crash). Also that passing a function as parameter fails, while providing the destination in place does not. The code is stripped down to the minimal reproducible version. Any thoughts?

Boost

Answer 1

oleksiiIK OP

Jun ’24

Observing the same behaviour even without NavigationStack. It can be reproduced with simpler code.

Xcode 15.2, iOS 17.2.

struct ContentView: View {
    @Environment(\.openURL) private var openURL

    var body: some View {
        let _ = Self._printChanges()

        Text("Hello, world!")
    }
}

This code prints out:

ContentView: @self, @identity, _openURL changed.
ContentView: _openURL changed.

If I comment out openURL's Environment variable, the code prints out expected one redraw:

ContentView: @self changed.

This behaviour seems expected, but I cannot find any information on how to mitigate the redraws.

3

Answer 2

Slif OP

Nov ’24

Hiyooo adding my predicament to this list as well. If you happen to display a sheet/popover attached to this view, the redraws will cause them to close.

I'm actually OK with the redraws, so long as they don't close the sheet/popover :)

0