Can't assign a data value to a string - returns null - flutter

Question

In my code, am trying a assign a string value to an empty string and display on the page but it keeps showing null but when I print it out, it shows the value.

String fName = '';

@override
  void initState() {
    super.initState();
    getData();
  }

getData() async {
    FirebaseAuth _auth = FirebaseAuth.instance;
    User _firebaseUser = _auth.currentUser;
    print("============ MyHome ================");
    print(_firebaseUser.uid);
    _currentUser = await Database().getUserData(_firebaseUser.uid);
    if (_currentUser != null) {
      fName = _currentUser.firstName;
      print(_currentUser.firstName);
    } 
  }

database

Future<UserData> getUserData(String uid) async {
    UserData returnValue = UserData();

    try {
      DocumentSnapshot _docSnapshot =
          await _firestore.collection("users").doc(uid).get();
      returnValue.uid = uid;
      returnValue.firstName = _docSnapshot.data()["firstName"];
      returnValue.lastName = _docSnapshot.data()["lastName"];
      returnValue.userMail = _docSnapshot.data()["userMail"];
      returnValue.userType = _docSnapshot.data()["userType"];
      print("====================== on getData =============");
      print(returnValue.firstName);
    } catch (e) {
      print(e);
    }

    return returnValue;
  }

And whenever I try displaying the data it gives me null

Text("Hello, $fName"),

Please how do I do this or am I missing something

Peter Haddad · Accepted Answer · 2021-01-05 21:50:06Z

2

use setState to rebuild the widget tree with the value:

setState(() { 
fName = _currentUser.firstName;
});

answered Jan 5, 2021 at 21:50

Peter Haddad

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Comments

k rafiki · Accepted Answer · 2021-01-06 03:07:14Z

1

Since the getData function is async, flutter has already built the widget tree before getData finished. You'll now have to update the state using setstate.

setState(() {
   fName = _currentUser.firstName;
});

answered Jan 6, 2021 at 3:07

k rafiki

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Comments

nickname · Accepted Answer · 2021-01-06 04:04:51Z

1

You need to set the new state since we have made changes to the previous state (since your getData function is async.

setState(() {
   fName = _currentUser.firstName;
});

answered Jan 6, 2021 at 4:04

nickname

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