class IconContent extends StatelessWidget {
  const IconContent({Key? key, required this.icon, required this.label})
      : super(key: key);

  final IconData icon;
  final String label;

  @override
  Widget build(BuildContext context) {
    return Column(
      mainAxisAlignment: MainAxisAlignment.center,
      children: const [
        Icon(
          icon,
          size: 80.0,
        ),
        SizedBox(
          height: 15.0,
        ),
        Text(
          label,
          style: TextStyle(
            fontSize: 18.0,
            color: Color(
              0xFF8D8E98,
            ),
          ),
        ),
      ],
    );
  }
}

Im getting the error stated below multiple times. Can someone help me resolve them.

Arguments of a constant creation must be constant expressions.\nTry making the argument a valid constant, or use 'new' to call the constructor.

This is the code Im getting the errors on. Removing const didnt do anything :(

import 'package:flutter/material.dart';
import 'package:font_awesome_flutter/font_awesome_flutter.dart';

const Color midNightLight = Color(0xFF1D1E33);

class InputPage extends StatefulWidget {
  const InputPage({super.key});

  @override
  State<InputPage> createState() => _InputPageState();
}

class _InputPageState extends State<InputPage> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Center(
          child: Text('BMI Calculator'),
        ),
      ),
      body: SafeArea(
        child: Column(
          children: [
            Expanded(
              child: Row(
                // ignore: prefer_const_literals_to_create_immutables
                children: [
                  // ignore: prefer_const_constructors
                  Expanded(
                    flex: 2,
                    // ignore: prefer_const_constructors
                    child: ReusableCard(
                      colour: midNightLight,
                      // ignore: prefer_const_constructors
                      cardChild: IconContent(
                        icon: FontAwesomeIcons.mars,
                        label: 'MALE',
                      ),
                    ),
                  ),
                  // ignore: prefer_const_constructors
                  Expanded(
                    flex: 2,
                    // ignore: prefer_const_constructors
                    child: ReusableCard(
                      colour: midNightLight,
                      // ignore: prefer_const_constructors
                      cardChild: new IconContent(
                        icon: FontAwesomeIcons.venus,
                        label: 'FEMALE',
                      ),
                    ),
                  )
                ],
              ),
            ),
            Expanded(
              child: Row(
                // ignore: prefer_const_literals_to_create_immutables
                children: [
                  // ignore: prefer_const_constructors
                  Expanded(
                    flex: 2,
                    // ignore: prefer_const_constructors
                    child: ReusableCard(
                      colour: midNightLight,
                    ),
                  ),
                ],
              ),
            ),
            Expanded(
              child: Row(
                // ignore: prefer_const_literals_to_create_immutables
                children: [
                  // ignore: prefer_const_constructors
                  Expanded(
                    flex: 2,
                    // ignore: prefer_const_constructors
                    child: ReusableCard(
                      colour: midNightLight,
                    ),
                  ),
                  // ignore: prefer_const_constructors
                  Expanded(
                    flex: 2,
                    // ignore: prefer_const_constructors
                    child: ReusableCard(
                      colour: midNightLight,
                    ),
                  )
                ],
              ),
            ),
          ],
        ),
      ),
    );
  }
}

class IconContent extends StatelessWidget {
  const IconContent({Key? key, required this.icon, required this.label})
      : super(key: key);

  final IconData icon;
  final String label;

  @override
  Widget build(BuildContext context) {
    return Column(
      mainAxisAlignment: MainAxisAlignment.center,
      children: const [
        Icon(
          icon,
          size: 80.0,
        ),
        SizedBox(
          height: 15.0,
        ),
        Text(
          label,
          style: TextStyle(
            fontSize: 18.0,
            color: Color(
              0xFF8D8E98,
            ),
          ),
        ),
      ],
    );
  }
}

class ReusableCard extends StatelessWidget {
  const ReusableCard({
    Key? key,
    required this.colour,
    this.cardChild,
  }) : super(key: key);

  final Color? colour;
  final Widget? cardChild;

  @override
  Widget build(BuildContext context) {
    return Container(
      margin: const EdgeInsets.all(15.0),
      decoration: BoxDecoration(
        borderRadius: BorderRadius.circular(10.0),
        color: colour,
      ),
      child: cardChild,
    );
  }
}

CodePudding user response：

label will get on runtime, therefore it cant be const

class IconContent extends StatelessWidget {
  const IconContent({
    Key? key,
    required this.icon,
    required this.label,
  }) : super(key: key);

  final IconData icon;
  final String label;

  @override
  Widget build(BuildContext context) {
    return Column(
      mainAxisAlignment: MainAxisAlignment.center,
      children: [
        //remove const from here
        Icon(
          icon,
          size: 80.0,
        ),
        SizedBox(
          height: 15.0,
        ),
        Text(
          label,
          style: TextStyle(
            fontSize: 18.0,
            color: Color(
              0xFF8D8E98,
            ),
          ),
        ),
      ],
    );
  }
}

CodePudding user response：

Just remove the const from Column's children list. your lable and icon variable is not const and its value changes in different state because of that you can't use const for Column's children list. You also need to delete all those const from Row's children inside Expanded too.