How to pre-define propeties in classes Flutter - flutter

Question

I have created a CardText as a stateless widget and I will use it whenever I would be needing it. But I have a problem. As y'all can see, there are properties that I haven't marked as #required. What I want is these properties have a pre-defined value. Like, suppose the color property, it should be 0xFFFFFFFF until and unless I want somewhere to be as 0xFF000000. But these are final properties that can't be assigned on the basis of ??= method. Yes, I know, marking these properties as #required will require me to define each and every property whenever I call it. But having a pre-defined value will help me a lot to save time and a few lines of code.
Well, any expert out there, I don't know how to express the problem, so feel free to change the title. Thank you.
import 'package:flutter/material.dart';
import 'package:google_fonts/google_fonts.dart';
class CardText extends StatelessWidget {
final String data;
final int color;
final int fontSize;
final FontWeight fontWeight;
const CardText(
this.data, {
this.color,
this.fontSize,
this.fontWeight,
});
#override
Widget build(BuildContext context) {
return Text(
data,
style: GoogleFonts.openSans(
textStyle: TextStyle(
fontSize: fontSize,
fontWeight: fontWeight,
color: Color(color),
),
),
);
}
}

Answer 1

If your arguments are optional then you can give default it right away, like following
const CardText({
this.data,
this.color = 0xFFFFFFFF,
this.fontSize = 14,
this.fontWeight,
})

Answer 2

You can use the : colon syntax:
const CardText(
this.data, {
this.color,
this.fontSize,
this.fontWeight,
}) : color = 0xFFFFFFFF, data = "data"
The code after the colon will be executed before the code inside the curly brackets. From the linked question
The part after : is called "initializer list. It is a ,-separated list
of expressions that can access constructor parameters and can assign
to instance fields, even final instance fields. This is handy to
initialize final fields with calculated values.