How to make multiselected nested checkbox in dropdown #flutter?

• How to define the data model is the key to solving the problem

• Refer to the following example, hope it will help you

import 'package:flutter/material.dart';

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

  @override
  State<MyWidget> createState() => _MyWidgetState();
}

class _MyWidgetState extends State<MyWidget> {
  List<PannelModel> _pannelList = [
    PannelModel('dev_unit_test', false, [
      {'dev_zone_test': false},
      {'zone_A': false},
      {'zone_B': false},
      {'test_zone': false},
    ]),
    PannelModel('dev_unit', false, [
      {'dev_zone': false},
    ])
  ];
  var _pannelSwich = ValueNotifier<List<PannelModel>>([]);
  @override
  void initState() {
    super.initState();
  }

  @override
  void dispose() {
    _pannelSwich.dispose();
    super.dispose();
  }

  Widget _buildCheckBox(
      int modelIndex, MapEntry<int, Map<String, bool>> checkBoxMap) {
    var currenModel = _pannelSwich.value[modelIndex];
    var title = currenModel.checkBoxList![checkBoxMap.key].keys.single;
    var isChecked = currenModel.checkBoxList![checkBoxMap.key].values.single;
    return Row(
      children: [
        Checkbox(
            value: isChecked,
            onChanged: (val) {
              currenModel.checkBoxList![checkBoxMap.key]
                  .update(title, (value) => !isChecked);
              setState(() {});
            }),
        Text(title)
      ],
    );
  }

  Widget _buildPannel(List<PannelModel> swichValues) {
    return Column(
      children: [
        ...swichValues.asMap().entries.map((map) => ExpansionPanelList(
              elevation: 0,
              expandedHeaderPadding: EdgeInsets.all(0),
              expansionCallback: (_, __) {
                var pannelModel = _pannelSwich.value[map.key];
                pannelModel.isOpen = !(pannelModel.isOpen ?? false);
                _pannelSwich.value[map.key] = pannelModel;
                setState(() {});
              },
              children: [
                ExpansionPanel(
                    headerBuilder: (context, _) {
                      return ListTile(
                        title: Text(swichValues[map.key].title ?? ''),
                      );
                    },
                    canTapOnHeader: true,
                    isExpanded: (_pannelSwich.value[map.key].isOpen ?? false),
                    body: Column(
                      children: [
                        ..._pannelSwich.value[map.key].checkBoxList!
                            .asMap()
                            .entries
                            .map((checkBoxMap) =>
                                _buildCheckBox(map.key, checkBoxMap))
                      ],
                    ))
              ],
            ))
      ],
    );
  }

  @override
  Widget build(BuildContext context) {
    if (_pannelSwich.value.isEmpty) _pannelSwich.value = [..._pannelList];
    return Scaffold(
      body: Center(
          child: SingleChildScrollView(
              child: Column(
        children: [
          ValueListenableBuilder(
              valueListenable: _pannelSwich,
              builder: (context, swichValues, _) {
                return _buildPannel(swichValues);
              })
        ],
      ))),
    );
  }
}

class PannelModel {
  String? title;
  bool? isOpen;
  List<Map<String, bool>>? checkBoxList;
  PannelModel(this.title, this.isOpen, this.checkBoxList);
}