I cannot save my Data when separating classes

Question

I try to save CheckBox and RadioListTile data . I separated CheckBox and RadioList as Class . Here is My Codes , I tried a lot but I could not fix problem .

Answer 1

I have used your code to reproduce the issue. There are several issues, but no worries:

1- You should make your Child widgets(MyCheckBox, MyRadio) stateless, as their states are handled by the parent(HomePage).

2- In home_page.dart: HomePage calls the MyCheckBox widget like following:

home_page.dart

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

  @override
  State<HomePage> createState() => _HomePageState();
}

class _HomePageState extends State<HomePage> {
  TextEditingController _controller = TextEditingController();
  List<String> fruits = [];
  Helper myHelper = Helper();
  FutureServices future = FutureServices();
  Singers currentSinger = Singers.Ianis;
  @override
  initState() {
    super.initState();
    verileriOku1();
  }

  @override
  Widget build(BuildContext context) {
    print("build calıştı");
    return Scaffold(
        appBar: AppBar(title: Text("Storage App")),
        body: ListView(
          children: [
            Padding(
              padding: const EdgeInsets.all(8.0),
              child: TextFormField(
                controller: _controller,
                decoration: const InputDecoration(hintText: "İsim Giriniz"),
              ),
            ),
            MyRadio(),
            MyCheckBox(myValue: (value) {
              value = fruits;
              
            }),
            TextButton(
              onPressed: () {
                print(fruits);
                print(currentSinger);
              },
              child: Text("Yazdır"),
            ),
            TextButton(
                onPressed: () {
                  var object =
                      MyVariables(_controller.text, currentSinger, fruits);
                  myHelper.verileriKaydet(object);
                },
                child: Text("Kaydet")),
          ],
        ));
  }

  void verileriOku1() async {
    var info = await myHelper.verileriOku();

    setState(() {
      _controller.text = info.name;
      fruits = info.fruitList;
      currentSinger = info.singer;
    });
  }
}

As we can see, you are not assigning fruits correctly. So one possible solution could be:

MyCheckBox(myValue: (value) {
  fruits = value;        
}),

But in the following step, I decided to remove that Function. Instead, you will need to provide the list of fruits to the Child widget directly.

3- In my_check_box.dart: the MyCheckBox widget has a required Function to communicate with HomePage like the following:

my_check_box.dart

class MyCheckBox extends StatefulWidget {
  final Function myValue;
  MyCheckBox({Key? key, required this.myValue}) : super(key: key);

  @override
  State<MyCheckBox> createState() => _MyCheckBoxState();
}

So you needed to pass data between those widgets, and you chose to do it with Function. But since List is passed by reference in Dart language, you can use a List to pass values:

const MyCheckBox({
  Key? key,
  required this.savedFruits,
  required this.onChanged,
}) : super(key: key);

final List<String> savedFruits;
final void Function(bool? value, Meyveler meyve) onChanged;

Another positive side of using a List is now we can check correctly if these fruits are saved fruits:

my_check_box.dart

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

import '../models/enums.dart';

class MyCheckBox extends StatelessWidget {
  const MyCheckBox({
    Key? key,
    required this.savedFruits,
    required this.onChanged,
  }) : super(key: key);

  final List<String> savedFruits;
  final void Function(bool? value, Meyveler meyve) onChanged;

  @override
  Widget build(BuildContext context) => Column(
        children: [
          for (var meyve in Meyveler.values) check(meyve),
        ],
      );

  CheckboxListTile check(Meyveler meyve) => CheckboxListTile(
        title: Text(meyve.name),
        value: savedFruits.contains(describeEnum(meyve)),
        onChanged: (value) => onChanged(value, meyve),
      );
}

4- When it comes to the radio buttons, There is no connection between HomePage and MyRadio widgets. So take a look please the following solution related to this topic:

my_radio.dart

import 'package:flutter/material.dart';

import '../models/enums.dart';

class MyRadio extends StatelessWidget {
  const MyRadio({
    Key? key,
    required this.currentSinger,
    required this.onChanged,
  }) : super(key: key);

  final Singers currentSinger;
  final void Function(Singers singer) onChanged;

  @override
  Widget build(BuildContext context) => Column(
        children: [
          for (var singer in Singers.values) _radio(singer),
        ],
      );

  RadioListTile<Singers> _radio(Singers singer) => RadioListTile(
        title: Text(singer.name),
        value: singer,
        groupValue: currentSinger,
        onChanged: (_) => onChanged(singer),
      );
}

You can access the modified source code through GitHub.

If you have further questions, please don't hesitate to write in the comments.