Flutter Firebase 将 CollectionReference 转换为 List

Question

如何将此集合引用转换为列表。

final _firestore = FirebaseFirestore.instance;

var sRef = _firestore.collection("vehicles1");

这个方法我试过了，没用；

List<String> sRefList = sRef;

我的子类别类

class SubCategory {
  String name;
  List<String> models;

  SubCategory({this.name, this.models});

  Map<String, dynamic> toMap() {
    return {
      'name': name,
      'models': models,
    };
  }

  factory SubCategory.fromMap(Map<String, dynamic> map) {
    return SubCategory(name: map['name'], models: map['models']);
  }
}

还有这个转换代码

List<SubCategory> _subcategories = [];

_firestore.collection("vehicles1").snapshots().map((event) {
      event.docs.forEach((element) {
        _subcategories.add(SubCategory.fromMap(element.data()));
      });
      return _subcategories.reversed.toList();
    });

print(_subcategories);

Answer 1

FirebaseFirestore.instance
  .collection("colelction")
  .snapshots()
  .map((event) {
List<SubCategory> _subcategories = [];
event.docs.forEach((element) {
  _subcategories.add(SubCategory.fromMap(element.data()));
});
return _subcategories.reversed.toList();}),

Answer 2

class SubCountry {
String countryID;
String subCountryID;
String subCountryName;
SubCountry(
  {required this.countryID,
  required this.subCountryID,
  required this.subCountryName});

Map<String, dynamic> toMap() {
return {
  'country_id': countryID,
  'sub_country_id': subCountryID,
  'sub_country_name': subCountryName
};
}

factory SubCountry.fromMap(Map<String, dynamic> map) {
return SubCountry(
    countryID: map['country_id'],
    subCountryID: map['sub_country_id'],
    subCountryName: map['sub_country_name']);
}
}