Error when searching Firebase database with Flutter - The getter 'documents' isn't defined for the type 'QuerySnapshot'

Question

I want to create a search functionality for my project to fetch data from firestore. I am trying to create a Flutter search that searches documents from Firebase, but I am getting the error below:

The getter 'documents' isn't defined for the type 'QuerySnapshot'. Try importing the library that defines 'documents', correcting the name to the name of an existing getter, or defining a getter or field named 'documents'.

import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:flutter/material.dart';
import 'package:nethouese/pages/views/service2/searchService.dart';
class search extends StatefulWidget {
  @override
  _searchState createState() => _searchState();
}

class _searchState extends State<search> {
  TextEditingController _searchController= TextEditingController();
  var QueryResult=[];
  var tempsearchstore=[];
  @override
  void initialSearch(String value) {
    if(value.length==0){
      setState(() {
        QueryResult=[];
        tempsearchstore=[];
      });
    }
    var capitalizedValue=value.substring(0,1).toUpperCase()+value.substring(1);
    if(QueryResult.length==0&& value.length==1){
      SearchService().searchByName(value).then((QuerySnapshot docs){

        //Below are the two lines of code where the error is occurring.

        for(int i=0;i<QuerySnapshot.documents.length)
          QueryResult.add(docs.documents[i].data);
      });
    }

  }
Widget build(BuildContext context) {
    return Container(
      child: Column(
        children: [
          Text('serch bar'),
          TextField(
            onChanged: (value){
              initialSearch(value);
            },
            controller: _searchController,
            decoration: InputDecoration(
              prefixIcon: IconButton(
                color: Colors.black,
                icon: Icon(Icons.arrow_back),
                iconSize: 20.0,
                onPressed:(){
                  Navigator.of(context).pop();
                },
              )
            ),
          )
        ],
      ),
    );
  }
}

Below is a screenshot of the lines of code where the error is occuring:

i also get the same Error even if i chaged QuerySnapshot to DocumentSnapshot enter image description here

Answer 1

Try by changing this:

for(int i=0;i<QuerySnapshot.documents.length)
   QueryResult.add(docs.documents[i].data);

To this:

for(int i=0;i<docs.docs.length)
   QueryResult.add(docs.docs[i].data());

Explanation, you are using (QuerySnapshot docs) for the for loop, so what you want be checking, it the length of docs contained withing QuerySnapshot docs you referenced above.

In docs.docs[i].data(), the first docs is the name you used, the second docs is the actual list of documents retrieved from your Firebase query. I would advise to use better naming conventions, to cause less confusion, for example (QuerySnapshot queryResults).

Later on we can use queryResults.docs.length instead of docs.docs.length and docs.docs[i].data()

For example, this is more readable, and easier to debug, and would also work if you replace it in your code:

SearchService().searchByName(value).then((QuerySnapshot queryResults){
        for(int i=0;i<queryResults.docs.length)   // Use queryResults.documents.length, #if you are using the older version of Firestore dependency. 
          QueryResult.add(queryResults.docs[i].data());  //queryResults.documents[i].data()  #same reason as above
      });
    }

You also have to use data() to unlock the content of this document at this index "docs[i]", otherwise you would get "instanceOfDocumentSnapshot" instead of your actual results that you want to add to your List QueryResult.