Futter hack sample demo

main.dart

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  static const String _title = 'Super App';

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: _title,
      home: Scaffold(
        appBar: AppBar(
          title: const Text(_title),
          backgroundColor: Colors.blue,
        ),
        body: const MyStatefulWidget(),
      ),
    );
  }
}

class MyStatefulWidget extends StatefulWidget {
  const MyStatefulWidget({Key key}) : super(key: key);

  @override
  _MyStatefulWidgetState createState() => _MyStatefulWidgetState();
}

// Our secret password
const _secret = 'secret';

class _MyStatefulWidgetState extends State<MyStatefulWidget> {
  final _formKey = GlobalKey<FormState>();

  @override
  Widget build(BuildContext context) {
    return Form(
      key: _formKey,
      child: Padding(
        padding: const EdgeInsets.symmetric(horizontal: 10),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: <Widget>[
            TextFormField(
              decoration: const InputDecoration(
                hintText: 'Enter your password',
              ),
              validator: (value) {
                if (value != _secret) {
                  return 'Wrong password';
                }
                return null;
              },
            ),
            Padding(
              padding: const EdgeInsets.symmetric(vertical: 16.0),
              child: ElevatedButton(
                onPressed: () {
                  if (_formKey.currentState.validate()) {
                    showDialog(
                      context: context,
                      builder: (context) => Center(
                        child: Card(
                          color: Colors.white,
                          child: Container(
                            padding: const EdgeInsets.fromLTRB(80, 20, 80, 20),
                            child: const Text(
                              'You are in !!!',
                              style: TextStyle(fontSize: 30),
                            ),
                          ),
                        ),
                      ),
                    );
                  }
                },
                child: const Text('Submit'),
              ),
            ),
          ],
        ),
      ),
    );
  }
}