Search bar is not working

Hi everyone, I am new to Flutter and trying to build a simple chatting app using Android Studio. Everything has been on a smooth path but I encounter one problem which is my searching bar does not show any suggestions when I search. Here’s my source code:

import 'package:chattingapp1/services/database.dart';
import 'package:chattingapp1/widgets/widget.dart';
import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:flutter/material.dart';

class SearchScreen extends StatefulWidget {
  @override
  _SearchScreenState createState() => _SearchScreenState();
}

class _SearchScreenState extends State<SearchScreen> {

  DatabaseMethods databaseMethods = new DatabaseMethods();
  TextEditingController searchTextEditingController = new TextEditingController();
  QuerySnapshot searchSnapshot;

  initiateSearch() {
    databaseMethods
        .getUserByUsername(searchTextEditingController.text)
        .then((val){
     setState(() {
       searchSnapshot = val;
     });
    });
  }

  Widget searchList(){
    return searchSnapshot != null ? ListView.builder(
       itemCount: searchSnapshot.documents.length,
        shrinkWrap: true,
        itemBuilder: (context, index){
          return SearchTile (
            userName: searchSnapshot.documents[index].data["name"],
            userEmail: searchSnapshot.documents[index].data["email"],
         );
        }) : Container();
       }

  @override
 void initState() {
    initiateSearch();
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: appBarMain(context),
      body: Container(
        child: Column(
          children: <Widget>[
            Container(
              color: Color(0x54FFFFFF),
              padding: EdgeInsets.symmetric(horizontal: 24, vertical: 14),
              child: Row(
                children: <Widget>[
                  Expanded(
                      child: TextField(
                        controller: searchTextEditingController,
                        style: TextStyle(
                          color: Colors.white),
                        decoration: InputDecoration(
                          hintText: "search username...",
                          hintStyle: TextStyle(color: Colors.white54),
                          border: InputBorder.none,
                           ),
                      )),

                  GestureDetector(
                    onTap: (){
                      initiateSearch();
                    },
                    child: Container(
                        height: 40,
                        width: 40,
                        decoration: BoxDecoration(
                          gradient: LinearGradient(
                              colors: [
                                const Color(0x36FFFFFF),
                                const Color(0x0FFFFFFF)
                              ]),
                             borderRadius: BorderRadius.circular(40),
                        ),
                        padding: EdgeInsets.all(12),
                        child: Image.asset("assets/images/search1.png")),
                  )
                ],
              ),
            ),
            searchList()
          ],
        ),
      ),
    );
  }
}

class SearchTile extends StatelessWidget {

  final String userName;
  final String userEmail;
  SearchTile({this.userName, this.userEmail});

  @override
  Widget build(BuildContext context) {
    return Container(
      child: Row(
        children: <Widget>[
          Column(
            children: <Widget>[
              Text(userName, style: simpleTextStyle(),),
              Text(userEmail, style: simpleTextStyle(),),
            ],
          ),
          Spacer(),
          Container(
            decoration: BoxDecoration(
             color: Colors.blue,
             borderRadius: BorderRadius.circular(30),
            ),
            padding: EdgeInsets.symmetric(horizontal: 16, vertical: 8),
            child: Text("Message"),
          ),
        ],
      ),
    );
  }
}

I really appreciate your help

i also got the same problem but in a different way because of null safety i cant use .data()[“name”] it asked me to use .data()![“name”] but then it tells me the error with the [] operator hope someone will help