不幸的是我得到了（见图）

我希望里面的文本...

struct ContentView: View {
    var body: some View {
        NavigationView {
            ZStack(alignment: .center) {

                Image("laguna")
                    .resizable()
                    .edgesIgnoringSafeArea(.all)
                    .scaledToFill()
                    .frame(width: UIScreen.main.bounds.width,height: UIScreen.main.bounds.height)

                VStack(alignment: .center) {
                    Text("just a test")
                        .font(.largeTitle)
                        .foregroundColor(Color.white)
                    Spacer()
                    Text ("not centered....why?")
                        .font(.largeTitle)
                        .foregroundColor(Color.white)

                }
                .zIndex(4)
                .navigationBarTitle("nav bar title")
            }
        }
    }
}