如何在我朋友集合中存储某人用户ID，以及如何使用firestore和Flutter检索用户数据？

Question

我想将我的朋友用户ID存储在我的朋友集合中。

我不知道如何在其他用户集合中存储某人详细信息。

下面是我获取CurrentUser的代码。

  Future<void> _getUserDoc() async {
    final FirebaseAuth _auth = FirebaseAuth.instance;
    final Firestore _firestore = Firestore.instance;

    FirebaseUser user = await _auth.currentUser();
    setState(() {
      userRef = _firestore.collection('users').document(user.uid);
    });
  }

USERS
-user1 (current user)
-name: John
-age: 20
--FRIENDS
----user2id
----user3id

-user2
-name: Richie
-age: 20
--FRIENDS
----user3id

   Padding(
                    padding:
                        const EdgeInsets.only(left: 20.0, right: 20.0, top: 10.0),
                    child: Text(
                      '20',
                      style: TextStyle(
                          fontFamily: 'Montserrat',
                          fontWeight: FontWeight.bold,
                          fontSize: 17.0),
                    ),
                  ),

Answer 1

我认为存储其他用户文档的最简单的方法是，如果将其他用户documentreference存储在当前用户中，您可以使用FutureBuilder构建它们

在红框中：friends是其他用户DocumentReference的数组

例如，您有用户模型

class UserModel {
  final int age;
  final String name;
  final List<DocumentReference> friends;

  UserModel(this.age, this.name, this.friends);

  // to get from Firestore
  UserModel.fromSnapshot(DocumentSnapshot snapshot):
    age = snapshot['age'],
    name = snapshot['name'],
    friends = List.from(snapshot['friends']);

}

FutureBuilder(
        future: currentUser.friends.first.get(), // this will take the first friend of current user
        // or you can query the list here with where 
        builder: (BuildContext context, AsyncSnapshot<QuerySnapshot> snapshot) {
          switch (snapshot.connectionState) {
            case ConnectionState.none:
              return Center(child: Text('Connection State none'));
            case ConnectionState.active:
            case ConnectionState.waiting:
              return Center(child: CircularProgressIndicator());
            case ConnectionState.done:
              if (snapshot.hasError)
                return Center(child: Text('Error: ${snapshot.error}'));
              return Padding(
                    padding:
                        const EdgeInsets.only(left: 20.0, right: 20.0, top: 10.0),
                    child: Text(
                      snapshot.data['age'],
                      style: TextStyle(
                          fontFamily: 'Montserrat',
                          fontWeight: FontWeight.bold,
                          fontSize: 17.0),
                    ),
                  );
          }
        });