Flutter iOS 音声メモアプリ開発（３） 編集用Dialogbox

import 'package:flutter/material.dart';
import 'main.dart';

class CardPage extends StatefulWidget {
  const CardPage({Key? key, required this.card_item}) : super(key: key);
  final Todo card_item;

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

class CardPageState extends State<CardPage> {
  late Todo item;
  final TextEditingController _textController = TextEditingController();
  @override
  void initState() {
    super.initState();
    item = widget.card_item;
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text(item.time.toIso8601String())),
      body: Container(
        padding: const EdgeInsets.all(10),
        child: Column(
          children: [
            Card(
              child: ListTile(
                title: Text(item.title),
                trailing: Text(item.sentiment,
                    style: Theme.of(context).textTheme.headlineSmall),
              ),
            ),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
          child: const Icon(Icons.edit),
          onPressed: () async {
            var ans = await _showEditDialog();
            if (_textController.text != '' && ans == 'save') {
              _editDataText(_textController.text);
              setState(() {});
            }
            if (ans == 'cancel') {
              _textController.text = '';
            }
          }),
    );
  }

  Future<void> _editDataText(String inputText) async {
    if (inputText != '') {
      item.title = _textController.text;
      item.save();
    }
  }

  Future<String> _showEditDialog() async {
    _textController.text = item.title;
    var result = await showDialog(
      context: context,
      builder: (_) {
        return AlertDialog(
          insetPadding: const EdgeInsets.all(8),
          title: const Text('音声メモの編集'),
          content: SingleChildScrollView(
            child: SizedBox(
              width: double.maxFinite,
              child: Column(children: [
                TextField(
                  autofocus: true,
                  maxLength: 100,
                  keyboardType: TextInputType.multiline,
                  maxLines: 5,
                  controller: _textController,
                  textInputAction: TextInputAction.newline,
                  decoration: const InputDecoration(
                      hintText: '',
                      labelText: '',
                      border: OutlineInputBorder(
                        borderRadius: BorderRadius.all(
                          Radius.circular(10),
                        ),
                      )),
                ),
              ]),
            ),
          ),
          actions: [
            TextButton(
              child: const Text('保存'),
              onPressed: () => Navigator.pop(context, 'save'),
            ),
            TextButton(
              child: const Text('キャンセル'),
              onPressed: () => Navigator.pop(context, 'cancel'),
            ),
          ],
        );
      },
    );
    return result;
  }
}