How to NOT show the current user in a Grid View? - flutter

Question

I have a function called getAllUsers() that returns all users from a database. The problem is that I want GridView.builder() to display all the users except the current user, but despite all the research I did, nothing seems to work out.
If i use the if condition like if(snapshot.data.documents[i].data["username"] != currentUserId within itemBuilder:, it returns a blank tile which represents the current user which creates a gap within the grid view. Thus, it makes the grid view look really bad.
I believe this problem could have been solved if I knew how to include the inequality query in the getAllUsers() method. But my understanding is that Firestore has yet to provide this function/argument.
HomeFragment class
Database _database = Database();
Stream _stream;
String currentUserId;
#override
void initState() {
getCurrentUserId();
getAllUsers();
super.initState();
}
getAllUsers() async {
return await _database.getAllUsers().then((val) {
if (mounted)
setState(() => _stream = val);
});
}
getCurrentUserId() async {
FirebaseUser currentUser = await FirebaseAuth.instance.currentUser();
currentUserId = currentUser.uid;
}
#override
Widget build(BuildContext context) {
return StreamBuilder(
stream: _stream,
builder: (context, snapshot) {
return snapshot.data == null ? Center(child: CircularProgressIndicator())
: Container(
padding: EdgeInsets.symmetric(horizontal: 20.0),
child:
GridView.builder(
gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
crossAxisCount: 2,
crossAxisSpacing: 8.0,
mainAxisSpacing: 8.0,
),
itemCount: snapshot.data.documents.length,
itemBuilder: (context, i) {
return Container(
child: Text(snapshot.data.documents[i].data["username"])
);
}
// etc etc..
Database class
getAllUsers() async {
return await _firestore.collection("users").snapshots();
}
I tried to use this, but _stream2 returns null
Stream _stream, _stream2;
getAllUsers() async {
return await _database.getAllUsers().then((val) {
if (mounted) {
List<String> list;
setState(() {
_stream = val;
_stream2 = _stream.where((snapshot) {
_querySnapshot = snapshot;
for (int i = 0; i < _querySnapshot.documents.length; i++)
list.add(_querySnapshot.documents[i].data["userId"]);
return list.contains(currentUserId) == false;
});
});
}
});
}
I also tried this, it is not working
getAllUsers() async {
Stream<QuerySnapshot> snapshots = await _database.getAllUsers();
_stream = snapshots.map((snapshot) {
snapshot.documents.where((documentSnapshot) {
return documentSnapshot.data["userId"] != currentUserId;
});
});
}

Answer 1

Maybe you can try something like this. You filter the query result:
getAllUsers() async {
final Stream<QuerySnapshot> snapshots = await _firestore.collection("users").snapshots();
return snapshots.map((snapshot) {
final result = snapshot.documents
.map((snapshot) => User.fromMap(snapshot.data)
.where((user) => user.id != currentUser.id)
.toList();
return result;
}
}
If you do not have an User class, you can replace some lines with this. But the result will be a list of Map<String, dynamic> instead of a list of User objects.
return snapshots.map((snapshot) {
final result = snapshot.documents
.map((snapshot) => snapshot.data
.where((user) => user['id'] != currentUser.id)
.toList();
return result;

Answer 2

This solution worked well for me.
firestore.collection('your collection').where('x', isNotEqualTo: auth.currentUser!.uid).snapshots();