Flutter十六进制ColorMaterialColor类型互转

　　十六进制颜色转Color类型class HexColor extends Color {   static int _getColorFromHex(String hexColor) {     hexColor = hexColor.toUpperCase().replaceAll(＂#＂, ＂＂);     if (hexColor.length == 6) {       hexColor = ＂FF$hexColor＂;     }     return int.parse(hexColor, radix: 16);   }    HexColor([String hexColor = ＂#ededed＂]) : super(_getColorFromHex(hexColor)); }Color转MaterialColor类型static MaterialColor createMaterialColor(Color color) {     List strengths = [.05];     Map swatch = {};     final int r = color.red, g = color.green, b = color.blue;      for (int i = 1; i < 10; i++) {       strengths.add(0.1 * i);     }     for (var strength in strengths) {       final double ds = 0.5 - strength;       swatch[(strength * 1000).round()] = Color.fromRGBO(         r + ((ds < 0 ? r : (255 - r)) * ds).round(),         g + ((ds < 0 ? g : (255 - g)) * ds).round(),         b + ((ds < 0 ? b : (255 - b)) * ds).round(),         1,       );     }     return MaterialColor(color.value, swatch);   }