Compartilhando o código do desafio "Subindo de nível"

import 'package:alura_flutter_curso_1/components/tasks.dart';
import 'package:alura_flutter_curso_1/data/task_inherited.dart';
import 'package:alura_flutter_curso_1/screens/form_screen.dart';
import 'package:flutter/material.dart';

class InitialScreen extends StatefulWidget {
  const InitialScreen({Key? key}) : super(key: key);

  @override
  State<InitialScreen> createState() => _InitialScreenState();
}

class _InitialScreenState extends State<InitialScreen> {
  double generalLevel = 0;
  double generalProgress = 0;
  double progressReference = 0;

  void updateGeneralLevel() {
    generalLevel = 0;
    progressReference = 0;

    setState(() {
      for (Task task in TaskInherited.of(context).taskList) {
        generalLevel += (task.level * task.dificuldade) / 10;
      }
      for (Task task in TaskInherited.of(context).taskList) {
        progressReference += 0.1 * task.dificuldade * 10 * task.dificuldade;
      }
      generalProgress = generalLevel / progressReference;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        backgroundColor: Colors.blue,
        title: Row(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                const Text('Tarefas', style: TextStyle(color: Colors.white)),
                Row(
                  mainAxisAlignment: MainAxisAlignment.spaceEvenly,
                  children: [
                    SizedBox(
                      width: 180,
                      child: LinearProgressIndicator(
                        value: generalProgress,
                        color: Colors.white,
                      ),
                    ),
                    Padding(
                      padding: const EdgeInsets.all(5.0),
                      child: Text(
                        'Level: ${generalLevel.toStringAsFixed(1)}',
                        style: const TextStyle(fontSize: 18, color: Colors.white),
                      ),
                    ),
                  ],
                )
              ],
            ),
            IconButton(
              onPressed: () {
                updateGeneralLevel();
              },
              icon: const Icon(
                Icons.refresh,
                color: Colors.white,
              ),
            )
          ],
        ),
      ),
      body: ListView(
        padding: const EdgeInsets.only(top: 8, bottom: 70),
        children: TaskInherited.of(context).taskList,
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: () {
          Navigator.push(
            context,
            MaterialPageRoute(
              builder: (contextNew) => FormScreen(
                taskContext: context,
              ),
            ),
          );
        },
        backgroundColor: Colors.blue[100],
        child: const Icon(Icons.add),
      ),
    );
  }
}