Provider new route example

provider_route_example.dart

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

void main() {
  runApp(App());
}

class App extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: FirstPage(),
    );
  }
}

class CounterState extends ChangeNotifier {
  int _counter = 0;
  int get counter => _counter;

  void incrementCounter() {
    _counter++;
    notifyListeners();
  }

  void decrementCounter() {
    _counter--;
    notifyListeners();
  }
}

class FirstPage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return ChangeNotifierProvider(
      create: (_) => CounterState(),
      builder: (context, child) {
        return Scaffold(
          body: Center(
            child: Text('Counter: ${context.watch<CounterState>().counter}'),
          ),
          floatingActionButton: FloatingActionButton.extended(
            onPressed: () {
              final _counter = context.read<CounterState>();
              Navigator.push(
                context,
                MaterialPageRoute(
                  builder: (context) => ChangeNotifierProvider.value(
                    value: _counter,
                    child: SecondPage(),
                  ),
                ),
              );
            },
            label: Text('Go to second page'),
          ),
        );
      },
    );
  }
}

class SecondPage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    final _counter = context.read<CounterState>();
    return Scaffold(
      appBar: AppBar(),
      body: Center(
        child: Row(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            ElevatedButton(
              onPressed: () => _counter.decrementCounter(),
              child: Text('Decrement counter'),
            ),
            SizedBox(width: 10),
            ElevatedButton(
              onPressed: () => _counter.incrementCounter(),
              child: Text('Increment counter'),
            ),
          ],
        ),
      ),
    );
  }
}