How to retrieve current user data from firebase? - flutter

Question

I tried this way, but i'm getting an error.
The error:
The method 'data' isn't defined for the type 'CollectionReference'. (undefined_method at [myapp] android\app\lib\useracc.dart:32)
void getData() async{
User? user = await FirebaseAuth.instance.currentUser;
var vari =FirebaseFirestore.instance.collection("users");
setState (() {
name = vari.data()['firstname'];
}
);
}
Signup/Register Page
Future<User?> _register(String fname,String lname ,String email, String password) async{
FirebaseAuth _auth = FirebaseAuth.instance;
FirebaseFirestore _firestore = FirebaseFirestore.instance;
try {
UserCredential userCrendetial = await _auth.createUserWithEmailAndPassword(email: emailController.text, password: passwordController.text);
print("Account created Succesfull");
userCrendetial.user!.updateDisplayName(fname);
userCrendetial.user!.updateDisplayName(lname);
await _firestore.collection('users').doc(_auth.currentUser!.uid).set({
"firstname": fname,
"lastname" : lname,
"email": email,
"uid": _auth.currentUser!.uid,
});
return userCrendetial.user;
} catch (e) {
print(e);
return null;
}
}
This is the user account from where i want to fetch info:
Please help. I'm struck here a long time.

Answer 1

You should retrieve the currentUser document then access its data:
void getData() async{
var vari = await FirebaseFirestore.instance
.collection("users")
.doc(FirebaseAuth.instance.currentUser.uid)
.get();
setState (() {
name = vari.data()['firstname'];
});
}

Answer 2

if you've saved your user's details in firestore and its document id is the same as that of user ID (which is preferred for ease of access and control), then:
var vari =FirebaseFirestore.instance.collection("users").doc(user!.uid).get();
This gets the document of the user, and the type is DocumentSnapshot.
Map<String,dynamic> userData = vari as Map<String,dynamic>;
now userData is stored in form of Map. suppose you want to access their 'name', so the syntax now goes like userData['name'].
Similarly other fields can be accessed from variable. It's preferred to store userData in a Provider to access it's contents anywhere in your app.
Full code snippet
void getData() async{
User? user = await FirebaseAuth.instance.currentUser;
var vari =FirebaseFirestore.instance.collection("users").doc(user!.uid).get();
Map<String,dynamic> userData = vari as Map<String,dynamic>;
setState (() {
name = userData['firstname']; //or name = userData['name']
}
);
}