Flutter - Drawer as sub-class not updating - class

Question

I'm a fairly inexperienced coder.
I have a Drawer which I have created as a separate class. The issue I'm having is the dynamic data for the Drawer is not populating.
I am expecting the data being retrieved from Shared Preferences should populate the third line of my view with the value of currUserL.
It's being evaluated correctly, and returns the value of currUserL to the console, but is not updated in the Drawer.
I've loaded up a about button (triggering the update method) that works when pressed manually, but data persists only while the drawer remains open. It reverts when the drawer is closed.
drawerPatient.dart
class DrawerPatient extends StatefulWidget {
DrawerPatient({Key key}) : super(key: key);
#override
_DrawerPatientState createState() => new _DrawerPatientState();
}
class _DrawerPatientState extends State<DrawerPatient> {
String currUserL = "nv3";
Future getPref() async {
SharedPreferences prefs = await SharedPreferences.getInstance();
currUserL = prefs.getString('currUserLast');
debugPrint('user: $currUserL');
}
#override
void initState() {
getPref();
}
void update() {
setState(() {
getPref();
});
}
#override
Widget build(BuildContext context) {
return Drawer(
child: new ListView(
children: <Widget>[
new DrawerHeader(
child: new Text('Patient Management'),
),
new ListTile(
title: new Text('search'),
onTap: () {},
),
new ListTile(
title: new Text(currUserL),
onTap: () {},
),
new Divider(),
new ListTile(
title: new Text('About'),
onTap: update,
),
],
));
}
}
userList.dart
class UserList extends StatefulWidget {
UserList({Key key, this.title}) : super(key: key);
final String title;
final String titleHead = "User List";
#override
_UserListState createState() => new _UserListState();
}
class _UserListState extends State<UserList> {
: sortStr}, headers: {"Accept": "application/json"});
setState(() {
data = json.decode(response.body);
});
}
#override
void initState() {
this.makeRequest();
// DrawerPatient().createState().update();
}
void _refresh() {
setState(() {});
}
#override
Widget build(BuildContext context) {
return new Scaffold(
appBar: new AppBar(
title: new Text("Patient List"),
drawer: new DrawerPatient(key: new UniqueKey()),
...
Drawer when opened
Drawer after clicking about (update)

Answer 1

So I found the answer, thanks to #Dinesh for pointing me in the right direction.
The answer was to put the setState as a dependency on the async get prefs.
Future getPref() async {
SharedPreferences prefs = await SharedPreferences.getInstance();
setState(() {
currUserI = prefs.getString('currUserId');
currUserF = prefs.getString('currUserFirst');
currUserL = prefs.getString('currUserLast');
debugPrint('user: $currUserL');
});
}

Answer 2

Can you try this,
Future getCurrentUser() async {
SharedPreferences prefs = await SharedPreferences.getInstance();
return prefs.getString('currUserLast');
}
void update() {
val tempName = getCurrentUser();
setState(() {
currUserL = tempName;
});
}
Reason: Basically wait for the async method before calling setState