How can i compare fields in firebase with flutter? - firebase

Question

I'm building a chat app and I'm trying to build a screen with the user history conversations with other users.
So basically what I am trying to do is taking all the values in the message field map (just the values, not the keys) like shown here:
And I want to compare it with the docs in the chatRoom like shown here:
If I compare them and the result came as true, I want to show the user the data that inside that chatRoom.
I'm really struggling to understand how to compare them
Thanks in advance.
Edit: here is the code:
final String chatId;
Chat({this.chatId});
#override
_ChatState createState() => _ChatState();
}
class _ChatState extends State<Chat> {
// Our own id
final String currentUserId = auth.currentUser?.uid;
// Loading state
bool isLoading = false;
// Query variable
Future<QuerySnapshot> chatHistoryResults;
// All the user rooms will be in this variable
List<String> roomsUserList = [];
// All the chat rooms will be in this variable
List<String> roomsChatList = [];
// All the history chat tickets will be here.
List<QuerySnapshot> tickets = [];
// Getting all the current user rooms in a list of Id rooms.
//TODO: fix the chat history
getRooms() async {
roomsUserList = [];
//roomsChatList = [];
DocumentSnapshot myDocUser = await userRef.doc(currentUserId).get();
Map<dynamic, dynamic> userRoomsMap = await myDocUser.get('messages');
userRoomsMap.forEach((key, value) {
roomsUserList.add(value);
});
print(roomsUserList);
roomsUserList.forEach((element) async {
String chatDoc = chatRef.doc(element).get().toString();
roomsChatList.add(chatDoc.toString());
});
print(roomsChatList);
}
// Build the story tickets here
buildStoryTickets() {
return FutureBuilder(
future: chatRef.get().then((snapshot) {
snapshot.docs.forEach((element) {});
}),
);
}
#override
Widget build(BuildContext context) {
return Provider<AuthService>(
create: (context) => AuthService(),
child: Scaffold(
backgroundColor: Colors.grey[350],
appBar: PreferredSize(
preferredSize: Size.fromHeight(55.0),
child: Header(
title: 'Chat',
),
),
body: ListView(
children: [
//buildStoryTickets(),
Container(
height: 100,
width: 100,
child: FlatButton(onPressed: () {
getRooms(); // Just to check
}),
),
],
),
),
);
}
}
I manage to insert all the values from the "messages" map inside a List called "roomUserList"

Answer 1

First, you can get the all the data from the User and chat room Using the StreamBuilder.
Once you have the messages and Chat room you can compare it by developing code logic.
PFB sample code to get data from firestore:
StreamBuilder<QuerySnapshot>(
stream: _firestore.collection('users').snapshots(),
builder: (context, snapshot) {
if (snapshot.hasData) {
//add your comparison logic here
);
}