I am trying to display a realtime chat-screen in flutter with with firebase-firestore (equal to the homescreen of whatsapp).
Working: Creating a list of all the contacts "peers". Have a Look at my Listview:
Container(
child: StreamBuilder(
stream:
//FirebaseFirestore.instance.collection('users').snapshots(),
FirebaseFirestore.instance
.collection('users')
.doc(currentUserId)
.collection('peers')
.snapshots(),
builder: (context, snapshot) {
if (!snapshot.hasData) {
return Center(
child: CircularProgressIndicator(
valueColor: AlwaysStoppedAnimation<Color>(themeColor),
),
);
} else {
return ListView.builder(
padding: EdgeInsets.all(10.0),
itemBuilder: (context, index) =>
buildItem(context, snapshot.data.documents[index]),
itemCount: snapshot.data.documents.length,
);
}
},
),
),
not working: Loading specific data for each tile like last message or name. I cant query this at the time of creating my first list (first query returns peer-ids, second returns userdata of a peer-id). My buildItem method consists of another streambuilder, however, as soon as the first streambuilder makes changes, the app freezes.
Widget buildItem(BuildContext context, DocumentSnapshot document) {
return StreamBuilder<DocumentSnapshot>(
stream: FirebaseFirestore.instance
.collection('users')
.doc(document.data()['peerId'])
.snapshots(),
builder: ...
Is this the proper way to nest streams? Simple Listviews are documented quite well, but i couldn't find a good example on this on google. Any help is appreciated.
Try creating your stream just once in initState and pass it onto this method:
//in initState
peersStream = FirebaseFirestore.instance
.collection('users')
.doc(currentUserId)
.collection('peers')
.snapshots(),
Then use stream: peersStream in the StreamBuilder.
Also, it is recommended to use widget-classes over methods for widgets: https://stackoverflow.com/a/53234826/5066615
Related
I'm currently using stream builder and future builder to call two collections at the same time. I'm having hard time because the stream builder refreshes every time the database changes. Here's my source code:
body: StreamBuilder<QuerySnapshot>(
stream: FirebaseFirestore.instance
.collection('thread')
.orderBy('published-time', descending: true)
.snapshots(),
builder: (context, snapshot) {
if (!snapshot.hasData) {
return Center(child: CircularProgressIndicator());
} else {
return snapshot.data!.docs.length > 0
? MediaQuery.removePadding(
removeTop: true,
context: context,
child: ListView(
shrinkWrap: true,
children: snapshot.data!.docs.map((DocumentSnapshot postInfo) {
return FutureBuilder<DocumentSnapshot>(
future: userCollection
.doc(postInfo.get('publisher-Id'))
.get(),
My variables are here:
final CollectionReference userCollection =
FirebaseFirestore.instance.collection('users');
final FirebaseAuth _auth = FirebaseAuth.instance;
Also tried calling two streambuilders:
body: StreamBuilder<QuerySnapshot>(
stream: FirebaseFirestore.instance
.collection('thread')
.orderBy('published-time', descending: true)
.snapshots(),
builder: (context, snapshot) {
if (!snapshot.hasData) {
return Center(child: CircularProgressIndicator());
} else {
return snapshot.data!.docs.length > 0
? MediaQuery.removePadding(
removeTop: true,
context: context,
child: ListView(
shrinkWrap: true,
children: snapshot.data!.docs
.map((DocumentSnapshot postInfo) {
return StreamBuilder<DocumentSnapshot>(
stream: userCollection
.doc(postInfo.get('publisher-Id'))
.snapshots(),
builder: (context, snapshot) {
if (snapshot.connectionState ==
ConnectionState.done) {
Map<String, dynamic> userInfo =
snapshot.data!.data()
as Map<String, dynamic>;
It doesn't look like there is a better way of calling two collections, but you can achieve less rebuilds by considering some optiomization steps mentioned in this article:
Only wrap the widget that should rebuild during a stream change inside a StreamBuilder
Use the Stream.map to map your stream object into an object that your widget needs to show in UI.
Use the Stream.distinct to create a _DistinctStream in case your widget shouldn’t rebuild when the stream provides the same value in a
row.
Create a separate _DistinctStream for StreamBuilders on initState so that they can save streamed values first if your
streamController streams a new value before the screen's first
build.
return StreamBuilder<QuerySnapshot>(
stream: FirebaseFirestore.instance
.collection("posting")
.where("authorId", isEqualTo: widget.uid)
//.orderBy("datetime")
.snapshots(),
builder: (context, AsyncSnapshot<QuerySnapshot> snapshot) {
if (!snapshot.hasData) {
return Container();
}
return ListView.builder(
itemCount: snapshot.data!.size,
physics: BouncingScrollPhysics(),
itemBuilder: (context, index) {
//return Container();
return ListView.builder(
shrinkWrap: true,
physics: BouncingScrollPhysics(),
itemCount: snapshot.data!.docs[index["replyCount"],
itemBuilder: (context, count) {
return StreamBuilder<QuerySnapshot>(
stream: FirebaseFirestore.instance
.collection('users')
.where("uid",
isEqualTo: snapshot.data!.docs[index]["reply"]
[count]["replyId"])
.snapshots(),
builder: (context, replyUser) {
for example, user has some posts written by this user.
some other user reply his posting.
then I want to show user who was writing post can be check reply alarm. order by reply time
This won't work:
.orderBy("reply.datetime")
For one, there is no field reply.datetime in your document. There is only reply[0].datetime, but I doubt you can specify an array item like that.
The common use-case for what you're trying to do is to order the documents on their latest reply timestamp. For such cases, the idiomatic approach is to store the timestamp of the latest reply as a top-level field in your document (say latestReplyDateTime) and order on that field.
I am having a trouble reading collection from firebase and saving values in a list.
I basically have a collection called 'brands' where I have car brands like this:
Firebase 'brands' collection screenshot
I need these car brands to be saved as a list like this, to be able to use it in a dropdown menu as items:
<String>[
'ferrari',
'mercedes',
'porsche',
]
I have tried using StreamBuilder (below) but it requires to return a widget and I do not actually need a widget to be returned, so below StreamBuilder is just an experiment "in progress".
Do you have any ideas?
final stream = FirebaseFirestore.instance
.collection('accounts')
.doc('dealers')
.collection(user!.uid)
.doc(dealerName)
.collection('brands')
.snapshots();
StreamBuilder(
stream: stream,
builder: (BuildContext context, AsyncSnapshot snapshot) {
if (snapshot.hasError) {
return Text('Error in receiving snapshot: ${snapshot.error}');
}
if (!snapshot.hasData) {
return Center(
child: CircularProgressIndicator(
backgroundColor: Theme.of(context).primaryColor,
),
);
}
return ListView.builder(
padding: EdgeInsets.all(8),
reverse: true,
itemCount: snapshot.data.docs!.length,
itemBuilder: (BuildContext context, int index) {
return Text(
snapshot.data.docs[index]['brandName'],
);
},
);
},
);
Once you get the data from firebase, loop through it and add the car brands to your list. Try this:
List<String> myBrands = [];
final dataRef = await FirebaseFirestore.instance
.collection('accounts')
.doc('dealers')
.collection(user!.uid)
.doc(dealerName)
.collection('brands')
.get();
dataRef.docs.forEach((doc) {
myBrands.add(doc.data()['brandName']);
});
You should then be able to use the myBrands list for your dropdown menu.
I am fetching data from two different firestore collections and this is my code
StreamBuilder(
stream: Firestore.instance.collection('items').snapshots(),
builder: (BuildContext context, snapshot){
if(snapshot.connectionState == ConnectionState.waiting){
return CupertinoActivityIndicator();
}
if(snapshot.data != null){
return ListView.builder(
itemCount: snapshot.data.documents.length,
itemBuilder: (context,index){
return Column(
children: <Widget>[
Text(snapshot.data.documents[index]['name']),
Text(snapshot.data.documents[index]['color']),
Text(snapshot.data.documents[index]['lifetime']),
Container(
child: StreamBuilder(
stream: Firestore.instance.collection('users')
.document(userid).collection('Quantity')
.document(snapshot.data.documents[index]['id']).snapshots(),
builder: (BuildContext context, snap){
if(snapshot.connectionState == ConnectionState.waiting){
return CupertinoActivityIndicator();
}
if(snap.data != null){
return Container(
child: Text(snap.data.documents.length)
);
}
},
),
)
],
);
});
}
},
)
It is giving me error but when I use futurebuilder inside streambuilder everything works fine and I also used stream broadcast but it is also giving me same error.
Here is the code which I used for broadcast stream
StreamController _controller = StreamController.broadcast();
Stream getItems() async*{
Firestore.instance.collection('items').snapshots().listen((data){
_controller.add(data);
})
yield* _controller.stream;
}
You shouldn't create a new Stream inside the StreamBuilder. When you do:
StreamBuilder(
stream: Firestore.instance.collection('items').snapshots(),
And
StreamBuilder(
stream: Firestore.instance.collection('users')
.document(userid).collection('Quantity')
.document(snapshot.data.documents[index]['id']).snapshots(),
Each time your build() function is called a new StreamBuilder is created, so Firestore.instance.collection()...snapshots() is called, returning a new Stream each time.
You should convert your widget to a StatefulWidget and initialize your Stream on initState(), passing it as a class variable to your StreamBuilder. The nested StreamBuilder can also be transformed into a StatefulWidget and created in place, but initialized on the same manner. Just pay attention that you might need a Key for showing it correctly on a ListView.
Also if you want to convert a Single Subscription Stream to a Broadcast Stream you just have to call asBroadcastStream to convert it.
I am trying to calculate the number of unread messages. In the first streambuilder I need to get all the document id's which match the first query.
Within that document ID I can then access the subcollection within that document and perform another query. I then need to access the result of that query.
However, within the attempt below the console outputs "past first stream" but does not enter the second streambuilder.
return StreamBuilder(
stream: Firestore.instance
.collection('conversations')
.where('user_id', isEqualTo: Provider.of<User>(context).id)
.snapshots(),
builder: (context, snapshot) {
if (!snapshot.hasData)
return Center(child: CircularProgressIndicator());
else {
print('past first stream');
StreamBuilder(
stream: Firestore.instance
.collection('conversations')
.document('#32#0#')
.collection('messages')
.where('customer_message_read', isEqualTo: false)
.snapshots(),
builder: (context, snapshot) {
print('im through second stream');
if (!snapshot.hasData)
return Center(child: CircularProgressIndicator());
print('nope');
QuerySnapshot querySnap = snapshot.data;
print(querySnap.documents.length);
return Center(child: CircularProgressIndicator());
},
);
return Scaffold(
backgroundColor: Colors.black,
body: _children[_selectedPage],
bottomNavigationBar: _bottomNavigationBar(context),
resizeToAvoidBottomPadding: true,
);
}
},
);
You've created second StreamBuilder but did not return it