SwiftUI:让按钮自动改变？

import SwiftUI

struct ContentView: View {
    @State private var buttonText = "点击我"

    var body: some View {
        Button(action: {
            self.buttonText = "已点击"
        }) {
            Text(buttonText)
                .padding()
                .background(Color.blue)
                .foregroundColor(.white)
                .cornerRadius(10)
        }
    }
}

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