Avoid StreamBuilder refreshing running SetState in Flutter - flutter

Question

I have a page which displays 2 elements, both of them are different StreamBuilder but the second one depends on the first one.
To make it more clear I display this:
Firebase documents (list)
Firebase user
If we sign out both StreamBuilder disappear. That's fine, but my problem comes when I need to select a document from the list:
return ListTile(
leading: FlutterLogo(size: 40.0),
title: Text(set["title"]),
selected: _selected[index],
trailing: Badge(
badgeColor: Colors.grey,
shape: BadgeShape.circle,
toAnimate: true,
onTap: () => setState(() => _selected[index] = !_selected[index]),
);
Everytime I do the SetState() I refresh the first StreamBuilder (not sure why) and with this the second one.
This is the list widget:
Widget _mySetsLists(BuildContext context) {
List<bool> _selected = List.generate(20, (i) => false);
return StreamBuilder(
stream: FirebaseAuth.instance.onAuthStateChanged,
builder: (context, snapshot) {
FirebaseUser user = snapshot.data;
if (snapshot.hasData) {
return StreamBuilder(
stream: Firestore.instance
.collection('users')
.document(user.uid)
.collection('sets')
.snapshots(),
builder: (BuildContext context, AsyncSnapshot snapshot) {
if (snapshot.hasData) {
return new ListView.builder(
shrinkWrap: true,
itemCount: snapshot.data.documents.length,
itemBuilder: (context, index) {
DocumentSnapshot set = snapshot.data.documents[index];
return ListTile(
leading: FlutterLogo(size: 40.0),
title: Text(set["title"]),
selected: _selected[index],
onTap: () => setState(() => _selected[index] = !_selected[index]),
);
},
);
} else {
return Center(
child: new CircularProgressIndicator(),
);
}
},
);
} else {
return Text("loadin");
}
},
);
}
}
And this is the user profile:
class UserProfileState extends State<UserProfile> {
#override
Widget build(BuildContext context) {
return SliverList(
delegate: SliverChildListDelegate(
[
_mySetsLists(context),
Divider(),
StreamBuilder<FirebaseUser>(
stream: FirebaseAuth.instance.onAuthStateChanged,
builder: (context, snapshot) {
if (snapshot.connectionState == ConnectionState.active) {
FirebaseUser user = snapshot.data;
if (user == null) {
return Text('not logged in');
}
return ListTile(
leading: CircleAvatar(
backgroundImage: NetworkImage(
user.photoUrl,
),
),
title: Text(user.displayName),
subtitle: Text(user.email),
trailing: new IconButton(
icon: new Icon(Icons.exit_to_app),
highlightColor: Colors.pink,
onPressed: () {
authService.signOut();
}),
);
} else {
return Text("loading profile"); // <---- THIS IS WHAT I SEE
}
},
),
],
),
);
}

Answer 1

I also went through the same difficulty, but this is the trick i used
var itemsData = List<dynamic>();
var _documents = List<DocumentSnapshot>();
#override
void initState() {
// TODO: implement initState
super.initState();
getData();
}
getData(){
Firestore.instance
.collection('users')
.document(currentUser.uid)
.collection('set')
.getDocuments()
.then((value) {
value.documents.forEach((result) {
setState(() {
_documents.add(result);
itemsData.add(result.data);
});
});
});
}
replace your listview builder will be like this
ListView.builder(
shrinkWrap: true,
itemCount: _documents.length,
itemBuilder: (context, index) {
return ListTile(
title:Text(itemsData[index]['name'])
)
})
Hope it helps!!

Answer 2

If you pretend to use setstat a lot using the stream you can download the data locally. So every reload will not download data again, but just show the local data.
First step: declare the variable that will store data locally.
QuerySnapshot? querySnapshotGlobal;
Then where you read the streamData, first check if the local data you just declared is empty:
//check if its empty
if(querySnapshotGlobal==null)
//as its empty, we will download it from firestore
StreamBuilder<QuerySnapshot>(
stream: _queryAlunos.snapshots(),
builder: (context, stream){
if (stream.connectionState == ConnectionState.waiting) {
return Center(child: CircularProgressIndicator());
}
else if (stream.hasError) {
return Center(child: Text(stream.error.toString()));
}
else if(stream.connectionState == ConnectionState.active){
//QuerySnapshot? querySnapshot = stream.data;
//instead of save data here, lets save it in the variable we declared
querySnapshotGlobal = stream.data;
return querySnapshotGlobal!.size == 0
? Center(child: Text('Sem alunos nesta turma'),)
: Expanded(
child: ListView.builder(
itemCount: querySnapshotGlobal!.size,
itemBuilder: (context, index){
Map<String, dynamic> map = querySnapshotGlobal!.docs[index].data();
//let it build
return _listDeAlunoswid(map, querySnapshotGlobal!.docs[index].id);
},
),
);
}
return CircularProgressIndicator();
},
)
else
//now, if you call setstate, as the variable with the data is not empty, will call it from here e instead of download it again from firestore, will load the local data
Expanded(
child: ListView.builder(
itemCount: querySnapshotGlobal!.size,
itemBuilder: (context, index){
Map<String, dynamic> map = querySnapshotGlobal!.docs[index].data();
return _listDeAlunoswid(map, querySnapshotGlobal!.docs[index].id);
},
),
),
Hope it helps you save some money!