samples/cupertino_gallery/lib/widgets/alert_dialog_page.dart

import 'package:flutter/cupertino.dart';

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

  @override
  Widget build(BuildContext context) {
    return CupertinoPageScaffold(
      navigationBar: const CupertinoNavigationBar(middle: Text('Alert Dialog')),
      child: Center(
        child: CupertinoButton(
          child: const Text('Show Alert Dialog'),
          onPressed: () {
            showCupertinoDialog<void>(
              context: context,
              builder: (BuildContext context) => CupertinoAlertDialog(
                title: const Text('Alert'),
                content: const Text('This is a sample alert dialog.'),
                actions: <CupertinoDialogAction>[
                  CupertinoDialogAction(
                    child: const Text('OK'),
                    onPressed: () {
                      Navigator.pop(context);
                    },
                  ),
                  CupertinoDialogAction(
                    isDefaultAction: true,
                    child: const Text('NO'),
                    onPressed: () {
                      Navigator.pop(context);
                    },
                  ),
                ],
              ),
            );
          },
        ),
      ),
    );
  }
}