How to initialize a QuerySnapshot type variable for a 1 document request to FireBase / Firestore with Flutter? - firebase

Question

I'm trying to get documents from a collection with the method FireBaseFirestore.instance.collection("users").where("name", isEqualTo : "something").get() which used to have a return type of QuerySnapshot.
My goal is to make a ListView or anything that can display like a ListView the result(s) of this request.
I have these functions :
This one is to get the documents with the where method
class DataBaseMeth {
getUserByUsername(String username) async{
return fsInstance.collection("users").where("name", isEqualTo: username).get();
}
}
This one is the widget with the result :
class SearchResultTile extends StatelessWidget {
final String username;
const SearchResultTile({
Key? key,
required this.username,
}) : super(key: key);
#override
Widget build(BuildContext context) {
return Container(
padding: const EdgeInsets.symmetric(vertical: 10.0, horizontal: 25.0),
child: Row(
children: [
Column(
children: [
Text(
username,
),//username
],
),
)
],
),
);
}
}
And finally the class of the page :
class SearchPage extends StatefulWidget {...}
class _SearchPageState extends State<SearchPage> {
DataBaseMeth dataBaseMethods = DataBaseMeth();
TextEditingController usernameSearchController = TextEditingController();
QuerySnapshot searchSnapshot; //the only way the code run is to replace the type by dynamic
initSearch(){
dataBaseMethods.getUserByUsername(usernameSearchController.text)
.then((result){
setState((){
searchSnapshot = result;
print("result : $searchSnapshot");
//print("result : ${searchSnapshot.docs[1].data.toString()}");
});
});
}
Widget searchList(){
return searchSnapshot != null ?
ListView.builder(
shrinkWrap: true,
itemCount: searchSnapshot.docs.length,
itemBuilder: (context, index) {
return SearchResultTile(
username: searchSnapshot.docs[index].data.toString(),
personalMessage: "personalMessage");
}
)
:
Container();
}
#override
void initState() {
searchList();
super.initState();
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: const MainAppBar(titleText: 'Search truc', mainPage: true),
body: Container(
padding: const EdgeInsets.symmetric(horizontal: 15.0, vertical: 10.0),
child: Column(
children: [
Row(
children: [
Expanded(
child: TextField(
controller: usernameSearchController,
decoration: textFieldInputDecoration("search username..."),
style: whiteText(),
),
),
IconButton(
onPressed: () {
initSearch();
},
icon: const Icon(Icons.search_outlined),
color: const Color(0xFFFFFFFF),
highlightColor: Colors.deepPurple,
splashColor: const Color(0xFF3A206B),
tooltip: "Search",
),
],
),
searchList()
],
),
),
);
}
}
The result of the print of searchSnapshot (when I put it on dynamic) is :
I/flutter (31401): result : Instance of '_JsonQuerySnapshot'
And nothing appears when I tap on the button.

Answer 1

Your fsInstance.collection("users").where("name", isEqualTo: username).get() returns a Future<QuerySnapshot> not a QuerySnapshot, so that's why you can't assign it to QuerySnapshot searchSnapshot. You can assign it to Future<QuerySnapshot> searchSnapshot though.
That also means that if you want to use it in your UI you'll have to either wrap it in a FutureBuilder or pass it to setState().