type 'Query' is not a subtype of type 'Stream<QuerySnapshot>?'

Question

in Flutter, I have collection called vendors and I am going to get collection base on the image of its collection

here is my code:

class _TopPickStoreState extends State<TopPickStore>{
StoreService _storeServices = StoreService();
@override
Widget build(BuildContext context){
   return Container(
   child: StreamBuilder<QuerySnapshot>(
     stream: _storeServices.getTopPickedStore(),
     builder: (BuildContext context, AsyncSnapshot<QuerySnapshot> snapShot){
      if(!snapShot.hasData)return CircularProgressIndicator();
      return Column(
        children: [
          Flexible(
              child: ListView(
                scrollDirection: Axis.horizontal,
                children: snapShot.data.docs.map((DocumentSnapshot document){
                  return Container(
                    width: 80,
                    child: Column(
                      children: [
                        Image.network(document['imageUrl']),
                      ]
                    ),
                  )
                ;}).toList(),
              ),
          )
        ],
      );
    }
    ),
);

} }

this is the function to get the collection:

import 'package:cloud_firestore/cloud_firestore.dart';


 class StoreService{
     getTopPickedStore(){
       return FirebaseFirestore.instance.collection('vendors')
       .where('accVerified', isEqualTo:true)
       .where('isTopPicked',isEqualTo: true)
       .orderBy('shopName');
     }
   }

and i got this error message:

type 'Query' is not a subtype of type 'Stream<QuerySnapshot ?'

can anyone help me to solve this?

Solution

Change it to this:

getTopPickedStore() async {
       return await FirebaseFirestore.instance.collection('vendors')
       .where('accVerified', isEqualTo:true)
       .where('isTopPicked',isEqualTo: true)
       .orderBy('shopName').snapshots();

You need to use snapshots to change it into a querysnapshot.

Comments

[Huthaifa Muayyad]

The problem is being caused by getTopPickedStore(), post this function. Because it's returning query object, but your streambuilder is querysnapshot. Decide which one of them you want to use, then it can be fixed

[ryan chandra]

i have put the getTopPickedStore() function, i hope you can explain more to me how to solve the problem. thank you very much

[Huthaifa Muayyad]

I added an answer. Basically what's written currently in the function is a query. Meaning it's a set of instructions to tell Firebase where and what to look for, but you don't tell it what to do afterwards. It has to be told to get() or snapshots(), to actually go to firebase, and get those documents, and then return them as a querysnapshot.