blue constant

MaterialColor const blue

The blue primary color and swatch.

link 
Icon(
  Icons.widgets,
  color: Colors.blue[400],
)

See also:

  • blueAccent, the corresponding accent colors.
  • indigo, lightBlue, and blueGrey, similar colors.
  • Theme.of, which allows you to select colors from the current theme rather than hard-coding colors in your build methods.

Implementation

static const MaterialColor blue = MaterialColor(
  _bluePrimaryValue,
  <int, Color>{
     50: Color(0xFFE3F2FD),
    100: Color(0xFFBBDEFB),
    200: Color(0xFF90CAF9),
    300: Color(0xFF64B5F6),
    400: Color(0xFF42A5F5),
    500: Color(_bluePrimaryValue),
    600: Color(0xFF1E88E5),
    700: Color(0xFF1976D2),
    800: Color(0xFF1565C0),
    900: Color(0xFF0D47A1),
  },
);