Show dialogs from unmounted context

main.dart

/*
 * Show dialogs from unmounted context
 * https://gist.github.com/PlugFox/f8f63c1ab3a63e49085b356281887435
 * https://dartpad.dev?id=f8f63c1ab3a63e49085b356281887435
 * Mike Matiunin <[email protected]>, 19 December 2025
 */

import 'dart:async';

import 'package:flutter/material.dart';

void main() => runZonedGuarded<void>(
  () => runApp(const App()),
  (error, stackTrace) => print('Top level exception'), // ignore: avoid_print
);

/// {@template app}
/// App widget.
/// {@endtemplate}
class App extends StatelessWidget {
  /// {@macro app}
  const App({super.key});

  @override
  Widget build(BuildContext context) => MaterialApp(
    title: 'Material App',
    home: Scaffold(
      appBar: AppBar(title: const Text('Material App Bar')),
      body: SafeArea(
        child: Center(
          child: Builder(
            builder: (context) => ElevatedButton(
              child: const Text('Hello World'),
              onPressed: () {
                showDoubleDialogs(context);
              },
            ),
          ),
        ),
      ),
    ),
  );
}

void showDoubleDialogs(BuildContext context) {
  // Get the navigator from the context
  // And use it to show the dialog even in unmounted situations
  final navigator = Navigator.maybeOf(context, rootNavigator: true);
  if (navigator == null) return;
  showDialog<void>(
    context: navigator.context,
    builder: (context) => AlertDialog(
      title: const Text('Dialog #1'),
      content: const Text(
        'First dialog\n'
        'Press button to pop it and show\n'
        ' another dialog after some delay.',
      ),
      actions: <Widget>[
        TextButton(
          onPressed: () {
            if (!navigator.mounted) return;
            navigator.maybePop();
            Timer(const Duration(seconds: 2), () {
              // We should not use just `context` here.
              // Because it could be unmounted
              if (!navigator.mounted) return;
              showDialog<void>(
                context: navigator.context,
                builder: (context) => AlertDialog(
                  title: const Text('Dialog #2'),
                  content: const Text(
                    'Second dialog\n'
                    'You can close it now.',
                  ),
                  actions: <Widget>[
                    TextButton(
                      onPressed: () {
                        if (!navigator.mounted) return;
                        navigator.maybePop();
                      },
                      child: const Text('Pop it'),
                    ),
                  ],
                ),
              );
            });
          },
          child: const Text('Pop it'),
        ),
      ],
    ),
  );
}