[Flutter] Firestore not accepting int? -> Unhandled Exception: FormatException: Invalid number...

In this part of my code, I need to pass a value as int to Cloud Firestore. In the past, this code used to work, but now its not working.

class AddPatientPage extends StatefulWidget {
const AddPatientPage({super.key});

@override
State<AddPatientPage> createState() => _AddPatientPageState();
}

class _AddPatientPageState extends State<AddPatientPage> {
// ignore: prefer_final_fields
GlobalKey<FormState> _formKey = GlobalKey<FormState>();
int id = 0;
bool isLoading = false;
@override
Widget build(BuildContext context) {
return GestureDetector(
onTap: () {
FocusManager.instance.primaryFocus?.unfocus();
},
child: Scaffold(
appBar: AppBar(
leading: backButton(context),
title: const Text('CADASTRO', style: TextStyle(color: Colors.white, fontWeight: FontWeight.bold),),
backgroundColor: const Color.fromARGB(255, 6, 158, 160),
actions: [
TextButton(
onPressed: () async {
FocusManager.instance.primaryFocus?.unfocus();
if (_formKey.currentState!.validate()) {
setState(() {
isLoading = true;
});
var doc =
FirebaseFirestore.instance.collection('patients').doc();
await doc.set({
'id': id,
}).whenComplete(() {
setState(() {
isLoading = false;
id = 0;
_formKey.currentState!.reset();
});
ScaffoldMessenger.of(context).showSnackBar(const SnackBar(
content: Text('Paciente adicionado'),
duration: Duration(seconds: 2),
backgroundColor: Color.fromARGB(255, 6, 158, 160),
));
});
}
},
child: const Text(
'Adicionar',
style: TextStyle(color: Colors.white, fontWeight: FontWeight.bold),
))
],
),
body: Center(
child: Padding(
padding: const EdgeInsets.symmetric(horizontal: 10),
child: Stack(
alignment: Alignment.center,
children: [
Form(
key: _formKey,
child: SingleChildScrollView(

child: ConstrainedBox(
constraints: const BoxConstraints(
maxWidth: 500
),
child: Column(
children: [
space(),
textFormField(
label: 'ID',
onChanged: (value) {
setState(() {
id = int.parse(value);
});
},
keyboardType: TextInputType.number,
inputFormatters: [MaskedInputFormatter('####')]),
],
),
),
),
),
isLoading == true
? Container(
height: double.infinity,
width: double.infinity,
alignment: Alignment.center,
child: const CircularProgressIndicator())
: const SizedBox.shrink()
],
),
),
),
),
);
}
}


Error message:

[ERROR:flutter/runtime/dart_vm_initializer.cc(41)] Unhandled Exception: FormatException: Invalid number (at character 1)
#0 int._handleFormatError (dart:core-patch/integers_patch.dart:125:7) integers_patch.dart:125
#1 int.parse (dart:core-patch/integers_patch.dart:51:14) integers_patch.dart:51
#2 _AddPatientPageState.build.<anonymous closure>.<anonymous closure> (package:mutirao24/add%20pages/add_patient_page.dart:154:44)
add_patient_page.dart:154
#3 State.setState (package:flutter/src/widgets/framework.dart:1203:30)
framework.dart:1203
#4 _AddPatientPageState.build.<anonymous closure> (package:mutirao24/add%20pages/add_patient_page.dart:153:33)
add_patient_page.dart:153
#5 _TextFormFieldState.reset (package:flutter/src/material/text_form_field.dart:398:31)
text_form_field.dart:398
#6 FormState.reset (package:flutter/src/widgets/form.dart:319:13) form.dart:319
#7 _AddPatientPageState.build.<anonymous closure>.<anonymous closure>.<anonymous closure>
(package:mutirao24/add%20pages/add_patient_page.dart:117:48)
add_patient_page.dart:117
#8 State.setState (package:flutter/src/widgets/framework.dart:1203:30)
framework.dart:1203
#9 _AddPatientPageState.<…>

Continue reading...