type '_JsonQuerySnapshot' is not a subtype of type 'Map<String, dynamic>' in type cast"

user_10778293 0
Viewed 4789

I have issues to display data from Firebase. Here is the code I used in my FutureBuilder.

This is the error that I got

"The following _CastError was thrown building FutureBuilder<QuerySnapshot<Object?>>(dirty, state: _FutureBuilderState<QuerySnapshot<Object?>>#c8a1c):
type '_JsonQuerySnapshot' is not a subtype of type 'Map<String, dynamic>' in type cast"

Code

import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:errandkaba_app/widgets/custom_action_bar.dart';
import 'package:flutter/material.dart';

class ServicePage extends StatefulWidget {
  final String? serviceId;
  const ServicePage({Key? key, this.serviceId}) : super(key: key);

  @override
  _ServicePageState createState() => _ServicePageState();
}

class _ServicePageState extends State<ServicePage> {
  final CollectionReference _servicesRef =
  FirebaseFirestore.instance.collection("cleaning");



  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Stack(
        children: [
          FutureBuilder (
            future: _servicesRef.get(),
            builder: (context, snapshot){
              //if has error
              if (snapshot.hasError) {
                return Scaffold(
                  body: Center(
                    child: Text("Error ${snapshot.error}"),
                  ),
                );
              }

              if(snapshot.connectionState == ConnectionState.done){
                Map<String, dynamic> documentData = snapshot.data as Map<String, dynamic>;

                return ListView(
                  children: [
                    Image.network(
                        "${documentData['images'][0]}"
                    ),
                  ],
                );

              }
google-cloud-firestore firebase dart flutter
5 Answers

try snapshot.data to snapshot.data!.data()

user_141463930

I did this FutureBuilder<DocumentSnapshot<Object?>>(future: _servicesRef.doc(widget.serviceId).get() and used this Map<String, dynamic> documentData = snapshot.data!.data() as Map<String, dynamic>; and it worked.

user_107782930

Change the FutureBuilder to FutureBuilder<QuerySnapshot> (or StreamBuilder< QuerySnapshot> for StreamBuilder)

Then cast the data this way

List<Map<String, dynamic>> documentData = snapshot.data?.docs.map((e) => e.data() as Map<String, dynamic>?).toList();
user_163628570 
FutureBuilder(
  future: FirebaseFirestore.instance.collection('users').doc(userId).get(),
  builder: (ctx,*AsyncSnapshot<DocumentSnapshot<Map<String,dynamic>>>* snapshot){
    return Text(
      snapshot.connectionState == ConnectionState.waiting
        ? 'Loading...'
        : snapshot.data!.data()!['userName'],
      .....

Provide the type and then it will work as expected else you will have to cast it to the right type before using data.data() prop and fun..

user_163398620

make your FurtureBuilder like this FurtureBuilder then snapshot.data.data()

user_137526530
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