flutter checkBoxの一例

final allChecked = checkBoxState('All checked', false);
final checkBoxList = [
  checkBoxState('Checked01', false),
  checkBoxState('Checked02', false),
  checkBoxState('Checked03', false),
  checkBoxState('Checked04', false),
  checkBoxState('Checked05', false),
];

@override
Widget build(BuildContext context) {
  return Scaffold(
    appBar: AppBar(
      title: Text('title'),
    ),
    body: ListView(
      children: [
        ListTile(
          onTap: () => onAllClicked(allChecked),
          leading: Checkbox(
            value: allChecked.value,
            onChanged: (bool? value) => onAllClicked(allChecked),
          ),
          title: Text(allChecked.title),
        ),
        const Divider(),
        ...checkBoxList.map(
          (e) => ListTile(
            onTap: () => onItemClicked(e),
            leading: Checkbox(
              value: e.value,
              onChanged: (bool? value) => onItemClicked(e),
            ),
            title: Text(e.title),
          ),
        )
      ],
    ),
  );
}

onAllClicked(checkBoxState Item) {
  final newValue = !Item.value;
  setState(() {
    Item.value = newValue;
    checkBoxList.forEach((element) {
      element.value = newValue;
    });
  });
}

onItemClicked(checkBoxState Item) {
  final newValue = !Item.value;
  setState(() {
    Item.value = newValue;
    if (!newValue) {
      allChecked.value = false;
    }else{
      final allListChecked = checkBoxList.every((element) => element.value);
      allChecked.value = allListChecked;
    }
  });
}

class checkBoxState {
  checkBoxState(this.title, this.value);

  String title;
  bool value;
}