Flutter/dart:: Adding a new field to class causing an error - flutter

Question

I added a new field to the class CloudNote, now I am getting an error!
I am getting the error when the app is trying to display a list.
Here is all my code without adding the field :: https://github.com/casas1010/flutter_firebase_vendor_management
I know its a simple issue, but I have tried to troubleshoot this for like an hour and have not made any progress
CloudNote class::
import 'package:cloud_firestore/cloud_firestore.dart';
import '/services/cloud/cloud_storage_constants.dart';
import 'package:flutter/foundation.dart';
/*
https://youtu.be/VPvVD8t02U8?t=87934
*/
#immutable
class CloudNote {
final String documentId;
final String jobCreatorId;
final String jobDescription;
final String jobState; // I added this
const CloudNote({
required this.documentId,
required this.jobCreatorId,
required this.jobDescription,
required this.jobState, // I added this
});
// acts as constructor
CloudNote.fromSnapshot(QueryDocumentSnapshot<Map<String, dynamic>> snapshot)
: documentId = snapshot.id,
jobCreatorId = snapshot.data()[jobCreatorIdColumn],
jobState = snapshot.data()[jobStateColumn], // I added this
jobDescription = snapshot.data()[jobDescriptionColumn] as String;
}
notes view ::
import 'package:flutter/material.dart';
import '/constants/routes.dart';
import '/enums/menu_action.dart';
import '/services/auth/auth_service.dart';
import '/services/cloud/cloud_note.dart';
import '/services/cloud/firebase_cloud_storage.dart';
import '/utilities/dialogs/logout_dialog.dart';
import '/views/notes/notes_list_view.dart';
class NotesView extends StatefulWidget {
const NotesView({Key? key}) : super(key: key);
#override
_NotesViewState createState() => _NotesViewState();
}
class _NotesViewState extends State<NotesView> {
late final FirebaseCloudStorage _notesService;
String get userId => AuthService.firebase().currentUser!.id;
#override
void initState() {
_notesService = FirebaseCloudStorage();
super.initState();
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text('Your jobs'),
actions: [
IconButton(
onPressed: () {
Navigator.of(context).pushNamed(createOrUpdateNoteRoute);
},
icon: const Icon(Icons.add),
),
PopupMenuButton<MenuAction>(
onSelected: (value) async {
switch (value) {
case MenuAction.logout:
final shouldLogout = await showLogOutDialog(context);
if (shouldLogout) {
await AuthService.firebase().logOut();
Navigator.of(context).pushNamedAndRemoveUntil(
loginRoute,
(_) => false,
);
}
}
},
itemBuilder: (context) {
return const [
PopupMenuItem<MenuAction>(
value: MenuAction.logout,
child: Text('Log out'),
),
];
},
)
],
),
body: StreamBuilder(
stream: _notesService.allNotes(jobCreatorId: userId),
builder: (context, snapshot) {
switch (snapshot.connectionState) {
case ConnectionState.waiting:
case ConnectionState.active:
if (snapshot.hasData) {
final allNotes = snapshot.data as Iterable<CloudNote>;
return NotesListView(
notes: allNotes,
onDeleteNote: (note) async {
await _notesService.deleteNote(documentId: note.documentId);
},
onTap: (note) {
Navigator.of(context).pushNamed(
createOrUpdateNoteRoute,
arguments: note,
);
},
);
} else {
return const CircularProgressIndicator();
}
default:
return const CircularProgressIndicator();
}
},
),
);
}
}
Error
The following _TypeError was thrown building NotesListView(dirty):
type 'Null' is not a subtype of type 'String'
The relevant error-causing widget was
NotesListView
lib/…/notes/notes_view.dart:72
When the exception was thrown, this was the stack
#0 new CloudNote.fromSnapshot
package:ijob_clone_app/…/cloud/cloud_note.dart:26
#1 FirebaseCloudStorage.allNotes.<anonymous closure>.<anonymous closure>
package:ijob_clone_app/…/cloud/firebase_cloud_storage.dart:39
#2 MappedListIterable.elementAt (dart:_internal/iterable.dart:413:31)
#3 ListIterator.moveNext (dart:_internal/iterable.dart:342:26)
#4 WhereIterator.moveNext (dart:_internal/iterable.dart:438:22)
#5 Iterable.length (dart:core/iterable.dart:497:15)
#6 NotesListView.build
package:ijob_clone_app/…/notes/notes_list_view.dart:26
#7 StatelessElement.build
package:flutter/…/widgets/framework.dart:4949
#8 ComponentElement.performRebuild
package:flutter/…/widgets/framework.dart:4878
#9 Element.rebuild
package:flutter/…/widgets/framework.dart:4604
#10 ComponentElement._firstBuild
package:flutter/…/widgets/framework.dart:4859
#11 ComponentElement.mount
package:flutter/…/widgets/framework.dart:4853
#12 Element.inflateWidget
package:flutter/…/widgets/framework.dart:3863
#13 Element.updateChild
package:flutter/…/widgets/framework.dart:3586
#14 ComponentElement.performRebuild
package:flutter/…/widgets/framework.dart:4904
#15 StatefulElement.performRebuild
package:flutter/…/widgets/framework.dart:5050
#16 Element.rebuild
package:flutter/…/widgets/framework.dart:4604
#17 BuildOwner.buildScope
package:flutter/…/widgets/framework.dart:2667
#18 WidgetsBinding.drawFrame
package:flutter/…/widgets/binding.dart:882
#19 RendererBinding._handlePersistentFrameCallback
package:flutter/…/rendering/binding.dart:378
#20 SchedulerBinding._invokeFrameCallback
package:flutter/…/scheduler/binding.dart:1175
#21 SchedulerBinding.handleDrawFrame
package:flutter/…/scheduler/binding.dart:1104
#22 SchedulerBinding._handleDrawFrame
package:flutter/…/scheduler/binding.dart:1015
#23 _invoke (dart:ui/hooks.dart:148:13)
#24 PlatformDispatcher._drawFrame (dart:ui/platform_dispatcher.dart:318:5)
#25 _drawFrame (dart:ui/hooks.dart:115:31)
════════════════════════════════════════════════════════════════════════════════
NotesListView ::
import 'package:flutter/material.dart';
import '/services/cloud/cloud_note.dart';
import '/utilities/dialogs/delete_dialog.dart';
/*
source: https://www.youtube.com/watch?v=VPvVD8t02U8&t=59608s
class creation :: 22:02:54
*/
typedef NoteCallback = void Function(CloudNote note);
class NotesListView extends StatelessWidget {
final Iterable<CloudNote> notes; // list of notes
final NoteCallback onDeleteNote;
final NoteCallback onTap;
const NotesListView({
Key? key,
required this.notes,
required this.onDeleteNote,
required this.onTap,
}) : super(key: key);
#override
Widget build(BuildContext context) {
return ListView.builder(
itemCount: notes.length,
itemBuilder: (context, index) {
final note =
notes.elementAt(index); // current note whose data we are returning
return ListTile(
onTap: () {
onTap(note);
},
title: Text(
note.jobDescription,
maxLines: 1,
softWrap: true,
overflow: TextOverflow.ellipsis,
),
trailing: IconButton(
onPressed: () async {
final shouldDelete = await showDeleteDialog(context);
if (shouldDelete) {
onDeleteNote(note);
}
},
icon: const Icon(Icons.delete),
),
);
},
);
}
}

Answer 1

This happens if you forget to update your Firestore entries. Atleast one of your CloudNote entries in Firestore does not have the field jobState. That's why Firestore returns a Null value. But it tries to map to String which leads to an exception.

Answer 2

Make sure to rerun the project.
or
flutter clean
and then
flutter run