Bloc (State Management) Counter App

import "package:flutter/material.dart";
import "package:flutter_bloc/flutter_bloc.dart";

void main()
{
  runApp(const MyApp());
}
class CounterBloc extends Cubit<int>
{
  CounterBloc() : super(0);

  @override
  void increment()
  {
    return emit(state + 1);
  }

  @override
  void decrement()
  {
    return emit(state - 1);
  }
}
class MyApp extends StatelessWidget
{
  const MyApp({super.key});
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: "Bloc Counter App",
      debugShowCheckedModeBanner: false,
      theme: ThemeData(
        primarySwatch: Colors.grey,
      ),
      home: BlocProvider(
        create: (context) {
          return CounterBloc();
        },
        child: const CounterPage2(),
      ),
    );
  }
}
class CounterPage2 extends StatelessWidget
{
  const CounterPage2({super.key});
  @override
  Widget build(BuildContext context) {
    final CounterBloc counterBloc = BlocProvider.of<CounterBloc>(context, listen: false);

    return Scaffold(
      appBar: AppBar(
        title: const Text("Bloc State Management"),
        centerTitle: true,
        backgroundColor: Colors.grey,
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text("Counter Value : ", style: Theme.of(context).textTheme.headlineLarge),
            BlocBuilder<CounterBloc, int>(
              builder: (context, state) {
                return Text("$state", style: Theme.of(context).textTheme.headlineLarge);
              },
            ),
            const SizedBox(height: 50.0),
            ElevatedButton(
              onPressed: () {
                Navigator.push(
                  context,
                  MaterialPageRoute(
                    builder: (context) {
                      return BlocProvider(
                        create: (context) {
                          return CounterBloc();
                        },
                        child: CounterPage3(title: "${counterBloc.state}"),
                      );
                    },
                  ),
                );
              },
              style: ElevatedButton.styleFrom(
                backgroundColor: Colors.blue,
                fixedSize: const Size(350.0,50.0),
              ),
              child: const Text("Go to Next Page",
                style: TextStyle(color: Colors.white, fontSize: 20.0),
              ),
            ),
          ],
        ),
      ),
      floatingActionButton: Row(
        mainAxisAlignment: MainAxisAlignment.end,
        children: <Widget>[
          FloatingActionButton(
            onPressed: () {
              counterBloc.increment();
            },
            heroTag: null,
            backgroundColor: Colors.blue,
            child: const Icon(Icons.add, color: Colors.white),
          ),
          const SizedBox(width: 20.0),
          FloatingActionButton(
            onPressed: () {
              counterBloc.decrement();
            },
            heroTag: null,
            backgroundColor: Colors.blue,
            child: const Icon(Icons.remove, color: Colors.white),
          ),
        ],
      ),
    );
  }
}
class CounterPage3 extends StatelessWidget
{
  const CounterPage3({super.key, required this.title});
  final String title;

  @override
  Widget build(BuildContext context) {

    return Scaffold(
      appBar: AppBar(
        title: const Text("Second Page"),
        centerTitle: true,
        backgroundColor: Colors.grey,
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text("This is the value of Counter Below : ",
              style: Theme.of(context).textTheme.headlineLarge),
            const SizedBox(height: 50.0),
            BlocBuilder<CounterBloc, int>(
              builder: (context, state) {
                return Text(title, style: Theme.of(context).textTheme.headlineLarge);
              },
            ),
          ],
        ),
      ),
    );
  }
}