Flutter Firestore - Load insted references in same model

Question

My project has a document with two or more references, sometimes I need to load these references data before display the data itself.

For example: "Item" document has: userRef , UniversityRef. I can load item without problem, but I can't understand how can load userRef and uniRef datas!

I am using a FirestoreListView Widget.

This is my code.

import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:flutter/material.dart';
import 'package:flutterfire_ui/firestore.dart';
import 'package:uobbook/models/item.dart';
import 'package:uobbook/services/firestore-reference-load.dart';
import 'package:uobbook/widgets/list_view_items.dart';

import '../models/college.dart';
import '../models/user.dart';

class HomePage extends StatefulWidget {
  @override
  _HomePageState createState() => _HomePageState();
}

class _HomePageState extends State<HomePage> {
  int tabIndexSelected = 0;
  String pageTitle = "Home Page";
  void onItemTapped(int index) {
    setState(() {
      tabIndexSelected = index;
    });
  }

  final itemsQuery = FirebaseFirestore.instance
      .collection('items')
      .orderBy('dateTime')
      .withConverter<Item>(
        fromFirestore: (snapshot, _) => Item.fromJson(snapshot.data()),
        toFirestore: (item, _) => item.toJson(),
      );

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(
          this.pageTitle,
          style: TextStyle(color: Colors.black),
        ),
        backgroundColor: Colors.white70,
      ),
      body: FirestoreListItems(itemsQuery: itemsQuery),
    );
  }
}

class FirestoreListItems extends StatelessWidget {
  const FirestoreListItems({
    Key key,
    @required this.itemsQuery,
  }) : super(key: key);

  final Query<Item> itemsQuery;

  @override
  Widget build(BuildContext context) {
    return FirestoreListView<Item>(
      query: itemsQuery,
      itemBuilder: (context, snapshot) {
        Item item = snapshot.data();
        return ListTile(
          //-- list to present all data of college, university and
          onTap: () => {print("tapped")},
          title: Text(item.title),
          subtitle: Text(
            "Subtitle here",
            overflow: TextOverflow.ellipsis,
            maxLines: 1,
            softWrap: false,
          ),
          leading: Icon(Icons.label),
          trailing: Column(
            children: [
              Icon(Icons.payment),
              Text(
                "15BD",
                style: TextStyle(color: Colors.black45),
              ),
            ],
          ),
        );
      },
    );
  }
}

Screenshot from item Firestore document

Answer 1

userRef data and uniRef data are in different collections. You should use multiple queries to load data from different collections.