Getting specific data values from Realtime Database in Flutter - firebase

Question

I'm working on a project with Firebase (Realtime database). In this project I will have a main screen with will have several buttons according to the user. The Buttons info are going to be stored inside the realtime database. This is basically a Home Automation project.
This is how my db looks:
The quantity, means how many buttons does that user have. button1 and button2 have the button characteristics. So what I'm attempting to do is.
When the user logs in. I have a Streambuilder that will check if the quantity has data. If I has if will run inside a For loop which will create the buttons in the user screen.
I having problem getting the specific values from the database, for example, getting the quantity and storing into a variable in the main screen.
This is how I'm attempting to get the quantity (I will use this code for getting other values too, later on) but it isn't working:
Future<int> receive_quantity() async{
final FirebaseUser user = await _auth.currentUser();
var snapshot = databaseReference.child(user.uid+"/buttons"+"/quantity").once();
var result;
await snapshot.then((value) => result = value);
print(result);
return result;
}
Error that I get:
_TypeError (type 'DataSnapshot' is not a subtype of type 'FutureOr<int>')
My StreamBuilder:
body: StreamBuilder(
stream: _auth.getButtonQuantity(),
initialData: 0,
builder: (context, snapshot) {
if (snapshot.hasError || snapshot.hasError){
return Container(color: Colors.red);
}
if (!snapshot.hasData || !snapshot.hasData){
return Center(child: CircularProgressIndicator());
}
if (snapshot.hasData || snapshot.hasData){
return GridView.count(
padding: EdgeInsets.all(15),
crossAxisSpacing: 20.0,
mainAxisSpacing: 20.0,
crossAxisCount: 3,
children: [
for (int i = 0; i < buttonquant; i++){
Button(),
},
GestureDetector(
onTap: () async{
_auth.receive_quantity();
},
child: Container(
color: Colors.black,
width: 150,
height: 150,
child: Icon(Icons.add, color: Colors.white,),
),
),
],
);
}
}
),
My Button:
class Button extends StatelessWidget {
const Button({
Key key,
}) : super(key: key);
#override
Widget build(BuildContext context) {
return GestureDetector(
onTap: (){
},
child: Container(
width: 150,
height: 150,
decoration: BoxDecoration(
color: Colors.black,
borderRadius: BorderRadius.circular(15)
),
child: Stack(
children: [
Positioned(
top: 10,
left: 10,
child: Icon(
Icons.lightbulb,
size: 35,
color: Colors.white,
),
),
Positioned(
top: 95,
left: 15,
child: Text("Televisao", style: TextStyle(color: Colors.white),),
),
],
),
),
);
}
}```

Answer 1

What you need to do is you need to get the value of the snapshot not using it directly:
Future<int> receive_quantity() async{
final FirebaseUser user = await _auth.currentUser();
var snapshot = await databaseReference.child(user.uid+"/buttons"+"/quantity").once();
var result = snapshot.value; //get the value here
print(result);
return result;
}
This is how you get the value in general:
databaseReference.once().then((DataSnapshot snapshot) {
print('Data : ${snapshot.value}');
});