firebase - 从Firebase检索用户的displayName和个人资料图片

Question

我正在做一个论坛移动应用程序，我想在用户上传帖子时显示其个人资料图片和用户名。我已经将一个ownerid字段(这是发布人员的uid)以及发布详细信息存储到firebase中。使用uid，我如何访问用户的显示名和个人资料图片？
这是我的帖子课:

class Post { //for forums


String title;
  String content;
  String timestamp;
  String imageurl;
  String username;
  String profilePicture;
  String documentid;
  String ownerid;
  Map<String, dynamic> saved = {};
  Map<String, dynamic> upvotes = {};
  


  Post(
    this.title,
    this.content,
    this.timestamp,
    this.imageurl,
    this.username,
    this.profilePicture,
    this.documentid,
    this.ownerid,
    this.saved,
    this.upvotes
    //this.image
  );

  Post.fromSnapshot(DocumentSnapshot snapshot) : 
  title = snapshot["title"],
  content = snapshot['content'],
  timestamp = snapshot['timestamp'],
  imageurl = snapshot['imageurl'],
  username = snapshot['username'],
  profilePicture = snapshot['profilePicture'],
  documentid = snapshot['documentid'],
  upvotes = snapshot['upvotes'],
  ownerid = snapshot['ownerid'],
  saved = snapshot['saved'];
}


FutureBuilder( 
              future: Firestore.instance.collection('users').document(post['ownerid']).get(),
              builder: (context, snapshot) {
                if (snapshot.connectionState == ConnectionState.done) {
                  return Text(snapshot.data['username'], style: TextStyle(fontWeight: FontWeight.bold,
                      fontSize: 16, decoration: TextDecoration.underline, color: Colors.grey[100]),
                   );
                } else {
                  return CircularProgressIndicator();
                }
              }, 
          ),

//在这里使用 future builder

Widget buildForum(BuildContext context, DocumentSnapshot post) {
    final forum = Post.fromSnapshot(post);
    
    return Container(
      child: Card(
        color: Colors.grey[850],
        shape: RoundedRectangleBorder(
    borderRadius: BorderRadius.circular(18.0)),
        child: InkWell(
          onTap: () {
            Navigator.push(context, MaterialPageRoute(
              builder: (context) => ForumDetails(forum: forum) //with this particular forum 
            ));
          },
      child: Padding(
        padding: EdgeInsets.only(top: 4, bottom: 4),
                child: Column(
                  children: <Widget>[
                    Padding(
                    padding: EdgeInsets.only(top: 4, bottom: 8),
                    child:
                    Row(children: <Widget>[
                      SizedBox(width: 10,),
                      Text('Uploaded on ', style: TextStyle(fontSize: 16, fontWeight: FontWeight.bold,
                      color: Colors.grey[400]),),
                      Text(post['timestamp'], 
                      style: TextStyle(fontSize: 16, fontWeight: FontWeight.bold,
                      color: Colors.grey[400]),),
                      Spacer(),   
                    ],),
                    ),
                    SizedBox(height: 10),
                    Row(children: <Widget>[
                      SizedBox(width: 10,),
                      CircleAvatar(
                      backgroundImage: post['profilePicture'] != null ?
                      NetworkImage(post['profilePicture']) : 
                      NetworkImage('https://genslerzudansdentistry.com/wp-content/uploads/2015/11/anonymous-user.png'),
                      backgroundColor: Colors.grey,
                      radius: 20,),
                      SizedBox(width: 10,),
                      //post['ownerid']
                    //   Text(post['username'], style: TextStyle(fontWeight: FontWeight.bold,
                    //   fontSize: 16, decoration: TextDecoration.underline, color: Colors.grey[100]),
                    // ),
               FutureBuilder( 
              future: Firestore.instance.collection('users').document(post['ownerid']).get(),
              builder: (context, snapshot) {
                if (snapshot.connectionState == ConnectionState.done) {
                  return Text(snapshot.data['username'], style: TextStyle(fontWeight: FontWeight.bold,
                      fontSize: 16, decoration: TextDecoration.underline, color: Colors.grey[100]),
                   );
                } else {
                  return CircularProgressIndicator();
                }
              }, 
          ),
                    
                    ],),
                    SizedBox(height: 10),
                    Padding( 
                    padding: EdgeInsets.only(top: 4, bottom: 8),
                    child:
                    Row(children: <Widget>[
                      SizedBox(width: 10,), 
                      Expanded(child:
                      Text(post['title'], style: TextStyle(fontSize: 18,
                      fontWeight:FontWeight.bold, color: Colors.grey[100]))),
                    ],)),
                    //display image if there is
                    (post['imageurl'] != null)  ?
                    Padding( 
                    padding: EdgeInsets.only(top: 4, bottom: 8),
                    child:
                    Column(
                      crossAxisAlignment: CrossAxisAlignment.stretch,
                      children: <Widget>[
                      SizedBox(width: 10,), 
                      ClipRRect(
                    borderRadius: BorderRadius.only(
                      topLeft: Radius.circular(8.0),
                      topRight: Radius.circular(8.0),
                      ),
                      child:  Image.network(post['imageurl']),
                      ),
                      //image of notes
                    ],),) : Container(height:0),
                    Padding(
                    padding: EdgeInsets.only(top: 4, bottom: 8),
                    child:
                    Row(children: <Widget>[
                      SizedBox(width: 10,),
                      Expanded(child:
                      Text(post['content'], style: TextStyle(fontSize: 16, color: Colors.grey[100]),
                      overflow: TextOverflow.ellipsis, maxLines: 2,),),
                    ],)),
                    SizedBox(height: 20),
                    Row(children: <Widget>[
                      SizedBox(width: 10,),
                      Icon(Icons.comment, size: 26,
                      color: Colors.tealAccent),
                       SizedBox(width: 6,),
                       Text('0', style: TextStyle(color: Colors.grey[100]),), //change to icons
                      Spacer(),
                      Icon(Icons.thumb_up, size: 26, color: Colors.tealAccent),
                      SizedBox(width: 6,),Text(post['upvotes'].values.where((e)=> e as bool).length.toString(), style: TextStyle(color: Colors.grey[100]),),
                    SizedBox(width: 10,)],)
                ],)
      ),),)
            );
    }

Answer 1

假设您在Firebase中已经有一个名为“用户”的集合，您将在登录时存储用户数据。还有一个名为“uid”的字段，您将在其中存储uid
在Firebase中检查具有相同uid的用户，然后提取详细信息

QuerySnapshot snapshot = awaitFirestore.instance.collection("users").where("uid",isEqualTo:ownerId).getDocuments()

//if you are sure that there is exactly one user with the same uid
Map<String,dynamic> userInfo = snapshot.documents[0].data;

为了保存阅读，我建议使用用户的uid来命名“用户”集合的文档ID，因为在这种情况下，您可以进行直接查询，例如

 DocumentSnapshot doc = await Firestore.instance.collection("users").document(ownerId).get();

//To access any fields on the document retrieved
String username = doc.data["username"] //assuming the fields name in the document 
                                       //is "username"