The following _TypeError was thrown building StreamBuilder<QuerySnapshot<Object?>>(dirty, state: _StreamBuilderBaseState<QuerySnapshot<Object?>, AsyncSnapshot<QuerySnapshot<Object?>>>#b3917): type 'Null' is not a subtype of type 'String'

[kaushik2103]

import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:firebase_auth/firebase_auth.dart';
import 'package:flutter/material.dart';
import 'package:residency/constants.dart';
import 'package:residency/widgets/home_screen_header.dart';

import '../../widgets/add_bar.dart';
import '../../widgets/big_card_details.dart';
import '../../widgets/big_card_owner_name.dart';
import '../../widgets/big_card_total_houses.dart';

class TotalHouseDetails extends StatefulWidget {
const TotalHouseDetails({Key? key}) : super(key: key);

@OverRide
State createState() => _TotalHouseDetailsState();
}

class _TotalHouseDetailsState extends State {
final CollectionReference _totalHouses =
FirebaseFirestore.instance.collection('add_houses');
Stream? _streamTotalHouses;

@OverRide
void initState() {
super.initState();
_streamTotalHouses = _totalHouses.snapshots();
}

@OverRide
Widget build(BuildContext context) {
double screenWidth = MediaQuery.of(context).size.width;
double screenHeight = MediaQuery.of(context).size.height;
return SafeArea(
child: Scaffold(
backgroundColor: Colors.black,
appBar: PreferredSize(
preferredSize: Size.fromHeight(screenHeight * 0.07),
child: AppBarWithIcon(
screenHeight: screenHeight,
appBarName: 'Houses',
),
),
body: Container(
width: double.infinity,
height: double.infinity,
decoration: const BoxDecoration(
color: Color(scaffoldBackgroundColor),
),
child: StreamBuilder(
stream: _streamTotalHouses,
builder: (BuildContext context, AsyncSnapshot snapshot) {
if (snapshot.hasError) {
return const Center(child: Text('Something went wrong!'));
}

          if (snapshot.connectionState == ConnectionState.active) {
            QuerySnapshot querySnapshot = snapshot.data;
            List<QueryDocumentSnapshot> listQueryDocumentSnapshot =
                querySnapshot.docs;
            return ListView(
              children: listQueryDocumentSnapshot
                  .map<Widget>((document) {
                    Map<String, dynamic> data =
                        document.data()! as Map<String, dynamic>;
                    return BigCardTotalHouses(
                      screenHeight: screenHeight,
                      screenWidth: screenWidth,
                      ownerName: data['owner_name'],
                      blockNo: data['block_no'],
                      mobileNo1: data['mobile_no'],
                      houseNo: data['house_no'],
                      mobileNo2: data['alternate_mobile_no'],
                      members: data['total_member'],
                    );
                  })
                  .toList()
                  .cast(),
            );
          }

          return const Center(
            child: CircularProgressIndicator(
              color: Color(primaryColor),
            ),
          );
        },
      ),
    ),
  ),
);

}
}
/*
Container(
width: double.infinity,
height: double.infinity,
decoration:
const BoxDecoration(color: Color(scaffoldBackgroundColor)),
child: SingleChildScrollView(
child: Column(
children: [
HomeScreenHeader(
screenWidth: screenWidth,
screenHeight: screenHeight,
homeScreenHeader: 'Total Houses',
),
SizedBox(
height: screenHeight * 0.03,
),
Padding(
padding: EdgeInsets.only(
left: screenWidth * 0.05,
right: screenWidth * 0.05,
),
child: Column(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
children: [
BigCardTotalHouses(
screenHeight: screenHeight,
screenWidth: screenWidth,
ownerName: 'Dhruv Tillu',
blockNo: 'A',
mobileNo1: '1234567890',
houseNo: '101',
mobileNo2: '1234567890',
members: '5',
),
],
),
),
],
),
),
),
*/