Multiple streams to firebase documents without disposing - firebase

Question

I am trying to add chatting to my app.
When my user starts a chat with a new user, I create a chatroom with a unique id in my Firebase database. I want my user to be notified with any updates of the chatroom document( eg: new messages) so when I create a chatroom, I also create a new stream to that chatroom document. Is there a problem with constantly listening to many documents with different streams without disposing the streams (because I want to get the latest results of any chatroom that user is a member of.)
This is my chatroom_screen code:
import 'package:flutter/material.dart';
import '../models/databse_management.dart';
class ChatroomScreen extends StatefulWidget {
static const String routeName = "/chatroom_screen";
#override
_ChatroomScreenState createState() => _ChatroomScreenState();
}
class _ChatroomScreenState extends State<ChatroomScreen> {
TextEditingController _messageTextEditingController = TextEditingController();
bool isChatroomExists;
Stream chatroomDocStream; //my initial stream variable which is null
#override
Widget build(BuildContext context) {
final Map<String, dynamic> passedArguments =
ModalRoute.of(context).settings.arguments;
//sedner details can be retrieved from currentUserDetails
final String senderId = passedArguments["senderId"];
final List<String> receiversIds = passedArguments["receiverIds"];
final String senderUsername = passedArguments["senderUsername"];
final List<String> receiverUsernames = passedArguments["receiverUsernames"];
final String chatroomId = passedArguments["chatroomId"];
if(chatroomDocStream == null){
chatroomDocStream = Firestore.instance.collection("chatrooms").document(chatroomId).snapshots(); //if no stream was created before (first time we build the widget), we connect a stream to this chatroom documentspecified with chatroomId
}
isChatroomExists = isChatroomExists == null
? passedArguments["isChatroomExists"]
: isChatroomExists;
final Image senderProfilePictureUrl =
passedArguments["senderProfilePicture"];
final List<Image> receiverProfilePictures =
passedArguments["receiverProfilePictures"];
final mediaQuery = MediaQuery.of(context).size;
final ThemeData theme = Theme.of(context);
//we get the values from the passed argument map
if (isChatroomExists) {
//load the previous chats
}
return Scaffold(
appBar: AppBar(
title: Row(
mainAxisAlignment: MainAxisAlignment.start,
children: <Widget>[
CircleAvatar(
backgroundImage: receiverProfilePictures[0]
.image, //right now only for 1 receiver but change it for multi members later
),
Container(
child: Text(receiverUsernames[0]),
margin: const EdgeInsets.only(left: 10),
),
],
),
),
body: //to do=> create a stream that is listening to the chatroom document for any changes
Stack(
children: <Widget>[
StreamBuilder(
//updates the chats whenever data of the chatroom document changes
stream: chatroomDocStream,
builder: (context, snapShot) {
return Column(
children: <Widget>[
Center(child: const Text("My chats"))
//message widgets go here
],
);
},
),
Positioned(
//positioned is used for positioning the widgets inside a stack. bottom: 10 means 10 pixel from bottom
bottom: 0,
child: Container(
padding: const EdgeInsets.symmetric(horizontal: 10, vertical: 5),
width: mediaQuery.width, //takes the total width of the screen
decoration: BoxDecoration(
color: theme.primaryColor.withOpacity(0.3),
),
child: Row(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
children: [
Expanded(
//always takes the remaining space (textField widget use this as its size https://stackoverflow.com/questions/45986093/textfield-inside-of-row-causes-layout-exception-unable-to-calculate-size)
child: Container(
padding: const EdgeInsets.symmetric(
horizontal:
10), //horizontal padding for the textfield widget
decoration: BoxDecoration(
color: theme.accentColor,
borderRadius: BorderRadius.circular(25),
border: Border.all(width: 2, color: theme.primaryColor),
),
child: TextField(
minLines: 1,
maxLines: 5,
controller: _messageTextEditingController,
decoration: const InputDecoration(
hintText: "Type something here...",
border: InputBorder
.none //removes all the border for textfield widget
),
),
),
),
Container(
child: Row(
//another row for buttons to be treated all toghether as a container in the parent row
children: <Widget>[
IconButton(
icon: const Icon(Icons.add),
onPressed: () {
//add media like image or pictures
},
),
IconButton(
icon: const Icon(Icons.camera_alt),
onPressed: () {
//take picture or video
},
),
IconButton(
icon: const Icon(Icons.send),
onPressed: () async {
if (_messageTextEditingController.text
.trim()
.isEmpty) {
return;
}
try {
await DatabaseManagement().sendMessage(
membersIds: [
senderId,
...receiversIds
], //extracts all the members of the list as seperate String items
//to do=>later on we have to get a list of the members as well
isChatroomExists: isChatroomExists,
chatroomId: chatroomId,
messageContent:
_messageTextEditingController.text,
senderId: senderId,
timestamp: Timestamp
.now(), //it's from firebase and records the time stamp of the sending message
);
if (isChatroomExists != true) {
isChatroomExists =
true; //after we sent a messsage, we 100% created the chatroom so it becomes true
}
} catch (e) {
print(
e.toString(),
);
return;
}
},
)
],
),
)
],
),
),
),
],
),
);
}
}
The idea is to have something like WhatsApp which you receive a notification of any updates in any chatroom you are a member of.

Answer 1

You can create a lot of snapshot listeners, but Google recommends a limit of 100 snapshot listeners per client:
Source: https://cloud.google.com/firestore/docs/best-practices?hl=en#realtime_updates