flutter_flutter/dev/a11y_assessments/lib/use_cases/text_button.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';
import '../utils.dart';
import 'use_cases.dart';

class TextButtonUseCase extends UseCase {
  TextButtonUseCase() : super(useCaseCategory: UseCaseCategory.core);

  @override
  String get name => 'TextButton';

  @override
  String get route => '/text-button';

  @override
  Widget build(BuildContext context) => const MainWidget();
}

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

  @override
  State<MainWidget> createState() => MainWidgetState();
}

class MainWidgetState extends State<MainWidget> {
  String pageTitle = getUseCaseName(TextButtonUseCase());
  final GlobalKey<FormState> _formKey = GlobalKey<FormState>();
  static const String fieldLabel = 'City';

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        backgroundColor: Theme.of(context).colorScheme.inversePrimary,
        title: Semantics(headingLevel: 1, child: Text('$pageTitle Demo')),
      ),
      body: Form(
        key: _formKey,
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: <Widget>[
            TextFormField(
              // The validator receives the text that the user has entered.
              validator: (String? value) {
                if (value == null || value.isEmpty) {
                  return 'Please enter some text';
                }
                return null;
              },
              errorBuilder: (BuildContext context, String errorText) {
                return Text(errorText, semanticsLabel: '$errorText in $fieldLabel');
              },
              decoration: const InputDecoration(labelText: fieldLabel),
            ),
            Padding(
              padding: const EdgeInsets.symmetric(vertical: 16),
              child: ElevatedButton(
                onPressed: () {
                  // Validate returns true if the form is valid, or false otherwise.
                  if (_formKey.currentState!.validate()) {
                    // If the form is valid, display a snackbar. In the real world,
                    // this might also send a request to a server.
                    ScaffoldMessenger.of(
                      context,
                    ).showSnackBar(const SnackBar(content: Text('Form submitted')));
                  }
                },
                child: const Text('Submit'),
              ),
            ),
          ],
        ),
      ),
    );
  }
}