SwiftUI - Get size of child?

Question

Is there any way to get the size of a child view in SwiftUI?

I\'m basically looking to do the UIKit equivalent of:

Answer 1

Basically, the answer at this point is to use a GeometryReader inside of the child's background(...) modifier.

// This won't be valid until the first layout pass is complete
@State var childSize: CGSize = .zero

var body: some View {
    ZStack {
        Text("Hello World!")
            .background(
                GeometryReader { proxy in
                    Color.clear.
                    .preference(key: SizePreferenceKey.self, value: proxy.size)
                }
            )
      }
      .onPreferenceChange(SizePreferenceKey.self) { preferences in
          self.childSize = preferences
      }
}

struct SizePreferenceKey: PreferenceKey {
    typealias Value = CGSize
    static var defaultValue: Value = .zero

    static func reduce(value: inout Value, nextValue: () -> Value) {
        value = nextValue()
    }
}