How to assign a Future variable to a class getter in Flutter - firebase

Question

I'm trying to read user data from Firebase via Streamer and assign them into properties of my User class. I have a FirabaseActions class doing firebase stuff. Here is the method that I use streamer to get data. It works perfectly, and print(user.data['userName']); give me the right result.
static Future<User> userDataStream(loggedInUserEmail) async {
final databaseReference = Firestore.instance;
User currentUser;
await for (var snapshot in databaseReference
.collection('users')
.where('email', isEqualTo: loggedInUserEmail)
.snapshots()) {
for (var user in snapshot.documents) {
print(user.data['userName']);
currentUser.userName = user.data['userName'];
currentUser.email = user.data['email'];
currentUser.userID = user.data['userID'];
currentUser.level = user.data['level'];
}
}
return currentUser;
}
The problem begin when I try to assign these user info to my class properties. Here is my User class. I got an error like below. It is about Future type but I can't handle it. What should I do?
Class 'Future' has no instance getter 'email'.
Receiver: Instance of 'Future'
Tried calling: email
class User {
String userName;
String userID;
String email;
int level;
User({this.userName, this.userID, this.level, this.email});
}

Answer 1

The first problem is that you cant assign an username like this
currentUser.userName = user.data['userName'];
Because currentUser is null. A simple solution to that is to replace
User currentUser; with User currentUser = User();
Second problem :
I think you should never search user by his email, rather by the UID that you get from
FirebaseUser user = await FirebaseAuth.instance.currentUser(),
So you would query for the user like this :
static Future<User> userDataStream() async {
final firestore = Firestore.instance;
final currentFirestoreUser = await FirebaseAuth.instance.currentUser();
User currentUser;
var query = await firestore
.collection('users')
.where('uid', isEqualTo: currentFirestoreUser.uid)
.getDocuments();
var user = query.documents.first.data;
currentUser = User(
userName: user['userName'],
userID: user['userID'],
level: user['level'],
email: user['email']);
return currentUser;
}
You could add UID as a method's parameter, or leave it inside the method.