DropdownButtonFormField 上的更改（DART/FLUTTER）

Question

我试图在列表中获取学生的值，并在下拉列表中加载他的教室。 当我的学生不在默认教室 (SIO1) 时，教室显示是错误的。 我点击笔，编辑当前学生以及定义他的所有参数的值。

请参阅以下代码...感谢您的宝贵时间！

import 'package:flutter/material.dart';
import 'models/Database.dart';
import 'controllers/PersonController.dart';
import 'models/Person.dart';

class MyHomePage extends StatefulWidget {
  const MyHomePage({super.key, required this.title});

  final String title;

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


class _MyHomePageState extends State<MyHomePage> {
  final _formKey = GlobalKey<FormState>();
  final TextEditingController _nameController = TextEditingController();
  final TextEditingController _ageController = TextEditingController();
  final PersonController _personController = PersonController();
  final DatabaseHelper _databaseHelper = DatabaseHelper();
  final TextEditingController _classController = TextEditingController();
  bool _isUpdating = false;
  int _selectedPersonId = 0;
  String _selectedClass = 'SIO1'; // Classe par défaut

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Padding(
        padding: const EdgeInsets.all(20.0),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.stretch,
          children: <Widget>[
            Container(
              margin: const EdgeInsets.all(10), // Marge autour du formulaire
              decoration: BoxDecoration(
                border: Border.all(color: Colors.grey),
                // Bordure autour du formulaire
                borderRadius: BorderRadius.circular(
                    10), // Coins arrondis du formulaire
              ),
              child: Form(
                key: _formKey,
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: <Widget>[
                    TextFormField(
                      controller: _nameController,
                      decoration: const InputDecoration(labelText: 'Nom'),
                      validator: (value) {
                        if (value == null || value.isEmpty) {
                          return 'Entrer votre nom';
                        }
                        return null;
                      },
                    ),
                    TextFormField(
                      controller: _ageController,
                      decoration: const InputDecoration(labelText: 'Age'),
                      validator: (value) {
                        if (value == null || value.isEmpty) {
                          return 'Entrer votre age';
                        }
                        return null;
                      },
                    ),
                    const SizedBox(height: 20),
                    const Text(
                      'Votre classe',
                      style: TextStyle(
                        fontSize: 16,
                      ),
                    ),
                    DropdownButtonFormField<String>(
                      value: _selectedClass,
                      onChanged: (String? newValue) {
                        setState(() {
                          _selectedClass = newValue!;
                        });
                      },
                      items: <String>['SIO1', 'SIO2']
                          .map<DropdownMenuItem<String>>((String value) {
                        return DropdownMenuItem<String>(
                          value: value,
                          child: Text(value),
                        );
                      }).toList(),
                    ),
                    Center(
                      child: Padding(
                        padding: const EdgeInsets.symmetric(vertical: 16.0),
                        child: ElevatedButton(
                          onPressed: _isUpdating ? _updatePerson : _addPerson,
                          style: ElevatedButton.styleFrom(
                            backgroundColor: Colors.blue,
                            textStyle: const TextStyle(fontSize: 18,),
                            padding: const EdgeInsets.symmetric(
                                horizontal: 30, vertical: 15),
                          ),
                          child: Text(
                            _isUpdating ? 'Mise à jour de l\'etudiant' : 'Ajout d\'un nouveau étudiant',
                            style: const TextStyle(
                                fontSize: 18, color: Colors.white),
                          ),
                        ),
                      ),
                    ),
                  ],
                ),
              ),
            ),
            Expanded(
              child: FutureBuilder<List<Person>>(
                future: _databaseHelper.getPersons(),
                builder: (context, snapshot) {
                  if (snapshot.connectionState == ConnectionState.waiting) {
                    return const Center(child: CircularProgressIndicator());
                  } else if (snapshot.hasError) {
                    return Center(child: Text('Error: ${snapshot.error}'));
                  } else {
                    return ListView.builder(
                      itemCount: snapshot.data!.length,
                      itemBuilder: (context, index) {
                        final person = snapshot.data![index];
                        return ListTile(
                          title: Text(person.name),
                          subtitle: Column(
                            crossAxisAlignment: CrossAxisAlignment.start,
                            children: [
                              Text('Age: ${person.age}'),
                              Text('Classe: ${person.studentClass}'),
                              // Ajout de la classe d'étudiants
                            ],
                          ),
                          trailing: Row(
                            mainAxisSize: MainAxisSize.min,
                            children: [
                              IconButton(
                                icon: const Icon(Icons.edit),
                                onPressed: () {
                                  setState(() {
                                    _isUpdating = true;
                                    _selectedPersonId = person.id;
                                    _nameController.text = person.name;
                                    _ageController.text = person.age.toString();
                                  });
                                },
                              ),
                              IconButton(
                                icon: const Icon(Icons.delete),
                                onPressed: () async {
                                  await _personController.deletePerson(
                                      context, person.id);
                                  // Rafraîchir la liste après suppression
                                  setState(() {});
                                },
                              ),
                            ],
                          ),
                        );
                      },
                    );
                  }
                },
              ),
            ),
          ],
        ),
      ),
    );
  }

  void _addPerson() async {
    String name = _nameController.text;
    int age = int.parse(_ageController.text);
    String selectedClass = _selectedClass;
    await _personController.addPerson(context, name, age, selectedClass);
    _clearForm();
  }

  void _updatePerson() async {
    String name = _nameController.text;
    int age = int.parse(_ageController.text);
    String selectedClass = _selectedClass;
    await _personController.updatePerson(
        context, _selectedPersonId, name, age, selectedClass);
    _clearForm();
  }

  void _clearForm() {
    _nameController.clear();
    _ageController.clear();
    setState(() {
      _isUpdating = false;
      _selectedPersonId = 0;
      _selectedClass = 'SIO1';
    });
  }
}

Answer 1

如果我正确理解问题，您希望在单击编辑按钮时在

person's classroom

上显示

dropdown

。

问题是您没有在

_selectedClass

上设置

setState

的值。像这样更改编辑按钮：

IconButton(
  icon: const Icon(Icons.edit),
  onPressed: () {
    setState(() {
      _isUpdating = true;
      _selectedPersonId = person.id;
      _nameController.text = person.name;
      _ageController.text = person.age.toString();
      _selectedClass = person.studentClass; // Added this one
    });
  },
),