Randomize defined hexColor in Flutter

I made cards and manage to do randomly colorize them with material Colors,

class RandomColor<Color> {
  List<MaterialColor> color = [
    Colors.green,
    Colors.blue,
    Colors.indigo,
  ];

  var index = Random().nextInt(3);

  MaterialColor colorRandomizer() {
    print(color[index]);
    return color[index];
  }
}

---

Problem is when i try it with hex color, flutter gives an error "Color isn't a function"
Also the code below is working if its not in Class but it returns only 1 random color.

class RandomHexColor<Color> {
  Color one = Color(0xff808000);
  Color two = Color(0xff608000);
  Color three = Color(0xff208080);

  List<Color> hexColor = [one, two, three];

  var indexColor = Random().nextInt(3);

  Color colorRandom() {
    print(hexColor[indexColor]);
    return hexColor[indexColor];
  }
}

full code can be found here https://gist.github.com/nevruzoglu/3db05f01706e5b2b4e75e24cded4a5b0