OnLayout Tutorial 09

OnLayout Tutorial 09.swift

func layoutWatcher(_ proxy: GeometryProxy) -> some View {
    /// This updates the height after each time the view 
    /// is updated.
    DispatchQueue.main.async {
        titleBarHeight = proxy.size.height
    }
    return Color.clear
        .onAppear {
           /// This updates the height when the view first
           /// appears.
           titleBarHeight = proxy.size.height
       }
}