LoadingOverlay.swift

import SwiftUI

class AppState:ObservableObject {
    @Published var showLoadingOverlay = false
    
    func loadData() {
        self.showLoadingOverlay = true
        DispatchQueue.main.asyncAfter(deadline: .now() + 0.1) {
            self.showLoadingOverlay = false
        }
    }
}

struct ContentView: View {
    @StateObject var state = AppState()
    var body: some View {
        VStack {
            Text("HELLO")
            Button {
                state.loadData()
            } label: {
                Text("BUTTON")
            }
        }
        
        .fullScreenCover(isPresented: $state.showLoadingOverlay) {
            Text("LOADING")
        }
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}