flutter/examples/api/lib/widgets/form/form.0.dart

// Copyright 2014 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

import 'package:flutter/material.dart';

/// Flutter code sample for [Form].

void main() => runApp(const FormExampleApp());

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

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(appBar: AppBar(title: const Text('Form Sample')), body: const FormExample()),
    );
  }
}

class FormExample extends StatefulWidget {
  const FormExample({super.key});

  @override
  State<FormExample> createState() => _FormExampleState();
}

class _FormExampleState extends State<FormExample> {
  final GlobalKey<FormState> _formKey = GlobalKey<FormState>();

  @override
  Widget build(BuildContext context) {
    return Form(
      key: _formKey,
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: <Widget>[
          TextFormField(
            decoration: const InputDecoration(hintText: 'Enter your email'),
            validator: (String? value) {
              if (value == null || value.isEmpty) {
                return 'Please enter some text';
              }
              return null;
            },
          ),
          Padding(
            padding: const EdgeInsets.symmetric(vertical: 16.0),
            child: ElevatedButton(
              onPressed: () {
                // Validate will return true if the form is valid, or false if
                // the form is invalid.
                if (_formKey.currentState!.validate()) {
                  // Process data.
                }
              },
              child: const Text('Submit'),
            ),
          ),
        ],
      ),
    );
  }
}