การนำทางระหว่างหน้าจอด้วย Navigator

import 'package:flutter/material.dart';

class HomeScreen extends StatelessWidget {
  const HomeScreen({super.key});

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text('Home')),
      body: Center(
        child: FilledButton(
          onPressed: () {
            Navigator.push(
              context,
              MaterialPageRoute(
                builder: (context) {
                  return const DetailScreen(
                    productName: 'Headphones',
                  );
                },
              ),
            );
          },
          child: const Text('View product'),
        ),
      ),
    );
  }
}

import 'package:flutter/material.dart';

class DetailScreen extends StatelessWidget {
  const DetailScreen({
    super.key,
    required this.productName,
  });

  final String productName;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text(productName)),
      body: Center(
        child: FilledButton(
          onPressed: () {
            Navigator.pop(context, true);
          },
          child: const Text('Add to cart'),
        ),
      ),
    );
  }
}

import 'package:flutter/material.dart';

Future<void> openDetail(BuildContext context) async {
  final added = await Navigator.push<bool>(
    context,
    MaterialPageRoute<bool>(
      builder: (context) {
        return const DetailScreen(
          productName: 'Headphones',
        );
      },
    ),
  );
  if (!context.mounted) return;
  final message = (added ?? false)
      ? 'Product added to cart'
      : 'No product added';
  ScaffoldMessenger.of(context).showSnackBar(
    SnackBar(content: Text(message)),
  );
}