why_navigator_is_bad.dart

why_navigator_is_bad.dart

import 'package:flutter/material.dart';

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

class BackButton extends StatelessWidget {
  const BackButton({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      initialRoute: 'home',
      onGenerateRoute: (route) {
        return MaterialPageRoute(builder: (context) {
          return Scaffold(
            appBar: AppBar(title: Text(route.name!)),
            body: Column(
              children: [
                Row(
                  children: [
                    Builder(builder: (context) {
                      return TextButton(
                        child: Text('increment top navigator'),
                        onPressed: () {
                          Navigator.of(context).pushNamed('not_home');
                        },
                      );
                    }),
                  ],
                ),
                Expanded(
                  child: NumberNavigator(
                    initialNumber: 0,
                    child: NumberNavigator(
                      initialNumber: 0,
                      child: Container(),
                    ),
                  ),
                ),
              ],
            ),
          );
        });
      },
    );
  }
}

class NumberNavigator extends StatelessWidget {
  const NumberNavigator({
    required this.initialNumber,
    required this.child,
    Key? key,
  }) : super(key: key);

  final int initialNumber;
  final Widget child;

  @override
  Widget build(BuildContext context) {
    return Navigator(
      initialRoute: '0',
      onGenerateRoute: (settings) {
        return PageRouteBuilder(
          transitionDuration: Duration.zero,
          pageBuilder: (context, _, __) {
            return Column(
              children: [
                Row(
                  children: [
                    Text(settings.name!),
                    IconButton(
                      icon: Icon(Icons.exposure_minus_1),
                      onPressed: () {
                        Navigator.of(context).pushNamed(
                            (int.parse(settings.name!) - 1).toString());
                      },
                    ),
                    IconButton(
                      icon: Icon(Icons.exposure_plus_1),
                      onPressed: () {
                        Navigator.of(context).pushNamed(
                            (int.parse(settings.name!) + 1).toString());
                      },
                    ),
                  ],
                ),
                Expanded(child: child),
              ],
            );
          },
        );
      },
    );
  }
}