Closure call with mismatched arguments: function '[]' in flutter - firebase

Question

** I am getting this error**
Closure call with mismatched arguments: function '[]'
Receiver: Closure: (dynamic) => dynamic from Function 'get':.
Tried calling: []("url")
Found: [](dynamic) => dynamic
my code where I am receiving the data from firestore is this..
import 'package:flutter/material.dart';
import 'package:riyazat_quiz/services/database.dart';
import 'package:riyazat_quiz/views/create_quiz.dart';
import 'package:riyazat_quiz/widgets/widgets.dart';
class Home extends StatefulWidget {
#override
_HomeState createState() => _HomeState();
}
class _HomeState extends State<Home> {
Stream quizStream;
DatabaseService databaseService = DatabaseService(); // this is to call the getQuizData() async{
return await FirebaseFirestore.instance.collection("Quiz").snapshots();
}
Widget quizList(){
return Container(
child: StreamBuilder(
stream:quizStream ,
builder: (context,snapshort){
return snapshort.data == null ? CircularProgressIndicator(): ListView.builder(
scrollDirection: Axis.vertical,
shrinkWrap: true,
itemCount : snapshort.data.documents.length ,
itemBuilder : (context,index){ return QuizTile(url:snapshort.data.documents[index].get['url'],
title:snapshort.data.documents[index].get['title'] ,
desc: snapshort.data.documents[index].get['desc'],);}
);
}
),
);
}
#override
void initState() {
databaseService.getQuizData().then((val){
setState(() {
quizStream =val;
});
});
super.initState();
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Center(
child: appBar(context),
),
backgroundColor: Colors.transparent,
elevation: 0.0,
brightness: Brightness.light,
),
body:
Column(
children: [
quizList(),
FloatingActionButton(
child: Icon(Icons.add),
onPressed: () {
Navigator.push(context,
MaterialPageRoute(builder: (context) => CreateQuiz()));
},
),
],
),
);
}
}
class QuizTile extends StatelessWidget {
final String url,title,desc;
QuizTile({#required this.url,#required this.title,#required this.desc});
#override
Widget build(BuildContext context) {
return Container(
child: Stack(
children: [
Image.network(url),
Container(
child: Column(
children: [
Text(title),
Text(desc),
],
),
)
],
),
);
}
}
can someone tell me where I am going wrong
ps: this is a quiz app where I am getting the data from the firestore,
using streams.
data saved on the firestore has three fields, "url", "title" "desc".
I want to retrieve them in the below widget and want to display them in a stack, but this error got me stuck in-between.

Answer 1

You need to do the following:
itemCount : snapshort.data.docs.length ,
itemBuilder : (context,index){
return QuizTile(url:snapshort.data.docs[index].data()['url'],
title:snapshort.data.docs[index].data()['title'] ,
desc: snapshort.data.docs[index].data()['desc'],
);
}
);
Since you are reference a collection, then you need to use docs which will retrieve a list of documents inside that collection:
https://github.com/FirebaseExtended/flutterfire/blob/master/packages/cloud_firestore/cloud_firestore/lib/src/query_snapshot.dart#L18
Then to access each field in the document, you need to call data()

Answer 2

The answer by #Peter Haddad is correct. Just to highlight the difference with an example from my own code:
The previous version of code which created the same error:
snapshot.data.docs[index].data["chatRoomID"]
Updated version of code which solved the error:
snapshot.data.docs[index].data()["chatRoomID"]

Answer 3

Updated Version:
snapshot.data[i]['Email'],
Future getRequests() async {
QuerySnapshot snapshot = await FirebaseFirestore.instance.collection("Buyer Requests").get();
return snapshot.docs;
}
body: FutureBuilder(
initialData: [],
future: getRequests(),
builder: (BuildContext context, AsyncSnapshot<dynamic> snapshot) {
indexLength = snapshot.data.length;
if (snapshot.hasData)
return SizedBox(
child: PageView.builder(
itemCount: indexLength,
controller: PageController(viewportFraction: 1.0),
onPageChanged: (int index) => setState(() => _index = index),
itemBuilder: (_, i) {
return SingleChildScrollView(
child: Card(
margin: EdgeInsets.all(10),
child: Wrap(
children: <Widget>[
ListTile(
leading: CircleAvatar(
backgroundImage: AssetImage(
'assets/images/shafiqueimg.jpeg'),
),
title: Text(
snapshot.data[i]['Email'],
style: TextStyle(
fontSize: 16,
fontWeight: FontWeight.w700,
color: Colors.black.withOpacity(0.7),
),
),
subtitle: Text(
snapshot.data[i]['Time'],
style: TextStyle(
color: Colors.black.withOpacity(0.6)),
),
),
Padding(
padding: const EdgeInsets.all(16.0),
child: Column(
crossAxisAlignment: CrossAxisAlignment.stretch,
children: [
Container(
decoration: BoxDecoration(
borderRadius:
BorderRadius.all(Radius.circular(5)),
color: Colors.grey[200],
),
padding: EdgeInsets.all(10),
child: Text(
snapshot.data[i]['Description'],
style: TextStyle(
color: Colors.black.withOpacity(0.6)),
),
),
SizedBox(
height: 8,
),
Container(
decoration: BoxDecoration(
borderRadius: BorderRadius.all(
Radius.circular(5)),
border: Border.all(
color: Colors.grey[300])),
child: ListTile(
leading: Icon(Icons.category_outlined),
title: Text(
'Category : ${snapshot.data[i]['Category']}',
style: TextStyle(
fontSize: 14,
color: Colors.grey,
),
),
),
),
SizedBox(height: 8),
Container(
decoration: BoxDecoration(
borderRadius: BorderRadius.all(
Radius.circular(5)),
border: Border.all(
color: Colors.grey[300])),
child: ListTile(
leading: Icon(Icons.location_pin),
title: Text(
snapshot.data[i]['Location'],
style: TextStyle(
fontSize: 14,
color: Colors.grey,
),
),
),
),
SizedBox(height: 8),
Container(
decoration: BoxDecoration(
borderRadius: BorderRadius.all(
Radius.circular(5)),
border: Border.all(
color: Colors.grey[300])),
child: ListTile(
leading: Icon(
Icons.attach_money,
color: kGreenColor,
),
title: Text(
'Rs.${snapshot.data[i]['Budget']}',
style: TextStyle(
fontSize: 14,
color: kGreenColor,
),
),
),
),
SizedBox(height: 8),
Container(
decoration: BoxDecoration(
borderRadius: BorderRadius.all(
Radius.circular(5)),
border: Border.all(
color: Colors.grey[300])),
child: ListTile(
leading: Icon(Icons.timer),
title: Text(
'Duration : ${snapshot.data[i]['Duration']}',
style: TextStyle(
fontSize: 14,
color: Colors.grey,
),
),
),
),
SizedBox(
height: 35,
),
RaisedButton(
padding: EdgeInsets.symmetric(vertical: 10),
child: Text('Send Offer'),
textColor: Colors.white,
color: Colors.green,
onPressed: () {
// Respond to button press
},
),
SizedBox(
height: 15,
),
Center(
child: Text(
"${i + 1}/$indexLength",
style: TextStyle(fontSize: 13),
),
),
],
),
),
],
),
),
);
},
),
);
else
return Center(
child: Text("Null"),
);
},
),

Answer 4

Given that you are referencing a collection, you must use docs to acquire a list of the documents included in that collection:
https://github.com/FirebaseExtended/flutterfire/blob/master/packages/cloud firestore/cloud firestore/lib/src/query snapshot.dart#L18
then you must call data() in order to access each field in the document.