Receiving Exception: The getter 'id' was called on null - flutter

Question

Hello StackOverflow users,
I got stuck and I am not able to understand why I am receiving this error. So, let me explain me what I am doing,
This is my Home Page where my body of the Scaffold is a PageView, In the PageView the first page is TimeLine(currentUser: currentUser) where currentUser stores the details of the User.
home.dart
Scaffold buildAuthScreen() {
return Scaffold(
body: PageView(
children: [
Timeline(currentUser: currentUser),
ActivityFeed(),
Upload(currentUser: currentUser),
Search(),
Profile(profileId: currentUser?.id),
],
controller: pageController,
onPageChanged: onPageChanged,
physics: NeverScrollableScrollPhysics(),
),
);
}
This is TimeLine Page, in this Page I am just trying to print 'currentUser.id' and while doing that I am receiving the exception (The getter 'id' was called on null).
timeline.dart
class Timeline extends StatefulWidget {
final User currentUser;
Timeline({this.currentUser});
#override
_TimelineState createState() => _TimelineState();
}
class _TimelineState extends State<Timeline> {
#override
Widget build(context) {
print('Timeline : ${widget.currentUser.id}');
return Scaffold(
body: Text('Timeline'),
);
}
}
I was looking up the code to see why I am receiving the exception and then I want to Upload Page, the 3rd page of the PageView and tried to print 'currentUser.id' and interestingly it worked fine here although I am receiving an exception here too but after that the user.id is getting printed..
upload.dart
class Upload extends StatefulWidget {
final User currentUser;
Upload({this.currentUser});
#override
_UploadState createState() => _UploadState();
}
class _UploadState extends State<Upload> {
#override
Widget build(BuildContext context) {
print('Upload : ${widget.currentUser.id}');
return Scaffold(
body: Text('Upload'),
);
}
}
I am confused why this behaviour is happening. If anyone needs more information ping me but I provided the basic structure and I am facing this problem.
<--Update-->
Code where I set currentUser
void createUserInFirestore() async{
/* check if user exists in users.collection in database */
final GoogleSignInAccount user = googleSignIn.currentUser;
DocumentSnapshot doc = await usersRef.doc(user.id).get();
/* If the user doesn't exist then we will create account */
if(!doc.exists) {
final username = await Navigator.push(
context,
MaterialPageRoute(builder: (context) => CreateAccount())
);
/* Create new user from userName in users collection */
usersRef.doc(user.id).set({
"id": user.id,
"username": username,
"photoUrl": user.photoUrl,
"email": user.email,
"displayName": user.displayName,
"bio": "",
"timestamp": timestamp,
});
doc = await usersRef.doc(user.id).get();
}
currentUser = User.fromDocument(doc);
print('Create User in firestore : ${currentUser.id}');
}
}
User model class
class User {
final String id;
final String username;
final String email;
final String photoUrl;
final String displayName;
final String bio;
User({
this.id,
this.username,
this.email,
this.photoUrl,
this.displayName,
this.bio,
});
factory User.fromDocument(doc) {
return User(
id: doc.data()['id'],
username: doc.data()['username'],
email: doc.data()['email'],
photoUrl: doc.data()['photoUrl'],
displayName: doc.data()['displayName'],
bio: doc.data()['bio'],
);
}
}