flutter 16进制色码转 Color

/// 十六进制颜色
1.0x开头 例如：0xfffefefe
class ColorUtil {
          
   
  /// hex, 十六进制值，例如：0xffffff,
  /// alpha, 透明度 [0.0,1.0]
  static Color hexColor(int hex,{
          
   double alpha = 1}){
          
   
    if (alpha < 0){
          
   
      alpha = 0;
    }else if (alpha > 1){
          
   
      alpha = 1;
    }
    return Color.fromRGBO((hex & 0xFF0000) >> 16 ,
        (hex & 0x00FF00) >> 8,
        (hex & 0x0000FF) >> 0,
        alpha);
  }
}
使用：ColorUtil.hexColor(0xffDfDfDf)

2.#开头  例如：#fefefe
class HexColor extends Color{
          
   

  static int _getColorfromString(String hexColor) {
          
   
    hexColor = hexColor.toUpperCase().replaceAll("#", "");
    if (hexColor.length == 6) {
          
   
      hexColor = "FF" + hexColor;
    }
    return int.parse(hexColor, radix: 16);
  }
  HexColor(String hexColor) : super(_getColorfromString(hexColor));
}
使用：static Color trans_red = HexColor(#4cE62929);