How do I traverse a view's subviews in SwiftUI?

To traverse a view's subviews in SwiftUI, you can use the new ForEachSubview API. This API allows you to iterate over the resolved subviews of a given view. Here's a brief explanation of how it works:

1. Declared vs. Resolved Subviews: In SwiftUI, declared subviews are the views you define in your code, while resolved subviews are the actual views that get rendered on the screen. For example, a ForEach view is a declared subview that generates multiple resolved subviews based on the data it iterates over.

2. Using ForEachSubview: The ForEachSubview API accepts a single view as its input and passes each of its resolved subviews into a trailing view builder. This allows you to transform these subviews into different kinds of views.

Here's a code snippet demonstrating how to use ForEachSubview:

struct ContentView: View {
    var body: some View {
        MyCustomContainer {
            Text("Subview 1")
            Text("Subview 2")
            ForEach(0..<3) { index in
                Text("Subview \(index + 3)")
            }
        }
    }
}

struct MyCustomContainer<Content: View>: View {
    let content: Content

    init(@ViewBuilder content: () -> Content) {
        self.content = content()
    }

    var body: some View {
        ForEachSubview(of: content) { subview in
            // Transform each subview here
            subview
                .padding()
                .background(Color.blue)
        }
    }
}

In this example, MyCustomContainer uses ForEachSubview to iterate over its subviews and apply some transformations.

For more detailed information, you can refer to the session Demystify SwiftUI containers at the 05:03 timestamp.