Flutter 可扩展分组列表视图

问：

我有一个现有的，我想转换（或替换为）一个小部件。我的数据源来自 Firebase Firestore。GroupedListViewExpandable

在所有“试图弄清楚”的情况下，我的代码都非常混乱，所以我会把它作为最后的手段，以保持帖子尽可能干净。它看起来像这样：

List<String> _headers = [];
List<Map<String, dynamic>> = [];
List finalList = [];
await FirebaseFirestore.instance.collection('collection').get().then((snapshot){
  for(final document in snapshot.docs){
    if(!_headers.contains(document.data()['headerDate'])){
      _headers.add(document.data()['headerDate']);
    }
  }
});

await FirebaseFirestore.instance.collection('collection').get().then((snapshot){
  for(headerItem in _headers){
    List<Map<String, dynamic>> tempData = [];
    for(final document in snapshot.docs){
      if(document.data()['headerDate'] == headerItem){
        tempData.add([{'name': document.data()['name'], 'idNo': document.data()['idNo'], document.data()['amount']});
      }
    }
    finalList.add([headerItem, tempData]);
  }
});

在此之后，我几乎被困住了，不知道如何映射每个数据下的数据以显示在可扩展的组中。headerItem

遵循这种结构是否安全，或者我是否有可能得到无序的结果？另外，有没有一种更简洁的方法来编写我目前拥有的代码？

感谢您对此的帮助！

编辑：

我仍然无法做到这一点。这是我对它的理解。

我的模型代码：

import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:collection/collection.dart';

class AttendanceData {
  static final _collection =
      FirebaseFirestore.instance.collection('attendance2').withConverter(
            fromFirestore: _fromFirestore,
            toFirestore: _toFirestore,
          );
  final String headerDate;
  final String tagName;
  final String tagId;
  final String workerType;
  final String teamName;
  final bool clockedIn;
  final String timeIn;
  final String timeOut;
  final String employeeId;

  AttendanceData(
      {required this.tagName,
      required this.tagId,
      required this.workerType,
      required this.teamName,
      required this.clockedIn,
      required this.timeIn,
      required this.timeOut,
      required this.employeeId,
      required this.headerDate});

  static AttendanceData _fromFirestore(
      DocumentSnapshot<Map<String, dynamic>> snapshot,
      SnapshotOptions? options,
      ) =>
      AttendanceData.fromSnapshot(snapshot);

  static Map<String, dynamic> _toFirestore(
    AttendanceData assignment,
    SetOptions? options,
  ) =>
      assignment.toFirestore();

    factory AttendanceData.fromSnapshot(
    DocumentSnapshot<Map<String, dynamic>> snapshot,
  ) {
    final staffData = snapshot.data();
    return AttendanceData(
      headerDate: staffData?['headerDate'],
      tagName: staffData?['tag_name'],
      tagId: staffData?['tag_id'],
      workerType: staffData?['worker_type'],
      teamName: staffData?['team_name'],
      clockedIn: staffData?['clockedIn'],
      timeIn: staffData?['timeIn'],
      timeOut: staffData?['timeOut'],
      employeeId: staffData?['employeeId'],
    );
  }

  Map<String, dynamic> toFirestore() {
    return {
      'headerDate': headerDate,
      'tag_name': tagName,
      'tag_id': tagId,
      'worker_type': workerType,
      'team_name': teamName,
      'clockedIn': clockedIn,
      'timeIn': timeIn,
      'timeOut': timeOut,
      'employeeId': employeeId,
    };
  }

  static Stream<QuerySnapshot<AttendanceData>> snapshots() =>
      _collection.snapshots();

  Map<String, List<dynamic>> groupByHeaderDate(collectionData) {
    return groupBy(collectionData, (collection) => collection.headerDate);
  }
}

然后在StreamBuilder

StreamBuilder(
  stream: AttendanceData.snapshots(),
  builder: (BuildContext context, AsyncSnapshot<QuerySnapshot> snapshot) {
    return staffData.keys.map((collection) =>
      ExpansionTile(
        title: collection.headerDate,
        subtitle: collection.tagName
      )).toList();