Not being able to read a Collection - flutter

Question

I have my flutter app connected to my firebase proyect and im having trouble logging in, since with my code im not being able to read the collection i created
import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:flutter/material.dart';
import 'package:flutter_keyboard_visibility/flutter_keyboard_visibility.dart';
import 'package:shared_preferences/shared_preferences.dart';
class LoginScreen extends StatefulWidget {
const LoginScreen({Key? key}) : super(key: key);
#override
_LoginScreenState createState() => _LoginScreenState();
}
class _LoginScreenState extends State<LoginScreen> {
TextEditingController idController = TextEditingController();
TextEditingController passController = TextEditingController();
double screenHeight = 0;
double screenWidth = 0;
Color primary = const Color(0xffeef444c);
late SharedPreferences sharedPreferences;
get HomeScreen => null;
#override
Widget build(BuildContext context) {
final bool isKeyboardVisible =
KeyboardVisibilityProvider.isKeyboardVisible(context);
screenHeight = MediaQuery.of(context).size.height;
screenWidth = MediaQuery.of(context).size.width;
return Scaffold(
resizeToAvoidBottomInset: false,
body: Column(
children: [
isKeyboardVisible
? SizedBox(
height: screenHeight / 16,
)
: Container(
height: screenHeight / 2.5,
width: screenWidth,
decoration: BoxDecoration(
color: primary,
borderRadius: const BorderRadius.only(
bottomRight: Radius.circular(70),
),
),
child: Center(
child: Icon(
Icons.person,
color: Colors.white,
size: screenWidth / 5,
),
),
),
Container(
margin: EdgeInsets.only(
top: screenHeight / 15,
bottom: screenHeight / 20,
),
child: Text(
"Login",
style: TextStyle(
fontSize: screenWidth / 18,
fontFamily: "NexaBold",
),
),
),
Container(
alignment: Alignment.centerLeft,
margin: EdgeInsets.symmetric(
horizontal: screenWidth / 12,
),
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
fieldTitle("Employee ID"),
customField("Enter your employee id", idController, false),
fieldTitle("Password"),
customField("Enter your password", passController, true),
GestureDetector(
onTap: () async {
FocusScope.of(context).unfocus();
String id = idController.text.trim();
String password = passController.text.trim();
if (id.isEmpty) {
ScaffoldMessenger.of(context).showSnackBar(const SnackBar(
content: Text("Employee id is still empty!"),
));
} else if (password.isEmpty) {
ScaffoldMessenger.of(context).showSnackBar(const SnackBar(
content: Text("Password is still empty!"),
));
} else {
QuerySnapshot snap = await FirebaseFirestore.instance
.collection("Employee")
.where('id', isEqualTo: id)
.get();
try {
if (password == snap.docs[0]['password']) {
sharedPreferences =
await SharedPreferences.getInstance();
sharedPreferences
.setString('employeeId', id)
.then((_) {
Navigator.pushReplacement(
context,
MaterialPageRoute(
builder: (context) => HomeScreen));
});
} else {
ScaffoldMessenger.of(context)
.showSnackBar(const SnackBar(
content: Text("Password is not correct!"),
));
}
} catch (e) {
String error = " ";
if (e.toString() ==
"RangeError (index): Invalid value: Valid value range is empty: 0") {
setState(() {
error = "Employee id does not exist!";
});
} else {
setState(() {
error = "Error occurred!";
});
}
ScaffoldMessenger.of(context).showSnackBar(SnackBar(
content: Text(error),
));
}
}
},
child: Container(
height: 60,
width: screenWidth,
margin: EdgeInsets.only(top: screenHeight / 40),
decoration: BoxDecoration(
color: primary,
borderRadius: const BorderRadius.all(Radius.circular(30)),
),
child: Center(
child: Text(
"LOGIN",
style: TextStyle(
fontFamily: "NexaBold",
fontSize: screenWidth / 26,
color: Colors.white,
letterSpacing: 2,
),
),
),
),
)
],
),
),
],
),
);
}
Widget fieldTitle(String title) {
return Container(
margin: const EdgeInsets.only(bottom: 12),
child: Text(
title,
style: TextStyle(
fontSize: screenWidth / 26,
fontFamily: "NexaBold",
),
),
);
}
Widget customField(
String hint, TextEditingController controller, bool obscure) {
return Container(
width: screenWidth,
margin: EdgeInsets.only(bottom: 12),
decoration: const BoxDecoration(
color: Colors.white,
borderRadius: BorderRadius.all(Radius.circular(12)),
boxShadow: [
BoxShadow(
color: Colors.black26,
blurRadius: 10,
offset: Offset(2, 2),
),
],
),
child: Row(
children: [
Container(
width: screenWidth / 6,
child: Icon(
Icons.person,
color: primary,
size: screenWidth / 15,
),
),
Expanded(
child: Padding(
padding: EdgeInsets.only(right: screenWidth / 12),
child: TextFormField(
controller: controller,
enableSuggestions: false,
autocorrect: false,
decoration: InputDecoration(
contentPadding: EdgeInsets.symmetric(
vertical: screenHeight / 35,
),
border: InputBorder.none,
hintText: hint,
),
maxLines: 1,
obscureText: obscure,
),
),
)
],
),
);
}
}
i have a collection called "Employee" with 2 parameters being "id" and "password". Please help and thanks in advance. im getting this error
if (e.toString() == > "RangeError (index): Invalid value: Valid value range is empty: 0") { setState(() { error = "Employee id does not exist!"; > });
which i think it means Im not being able to read the specific Collection, tried enabling internet connection in Android manifest but still not working`