How to get inside data in Future<Map<dynamic, dynamic>>? - flutter

Question

Future<Map> returnUserMap() async {
final FirebaseUser currentUser = await _auth.currentUser();
Map userMap = {
"UserName": currentUser.displayName,
"UserEmail": currentUser.email,
"UserUrl": currentUser.photoUrl
};
print("1");
print(userMap);
return userMap;
}
return value type is Instance of 'Future>'.
I want to get a UserName, how can I do it?

Answer 1

Your function returnUserMap() returns a Future<Map>. I suspect that the error you describe is not in the code snippet you copied.
Whenever the task to be performed may take some time, you will receive a future. You can wait for futures in an async function with await.
It is therefore recommended to use a so-called FutureBuilder in your build() function:
FutureBuilder<FirebaseUser>(
future: _auth.currentUser(),
builder: (BuildContext context, AsyncSnapshot snapshot) {
if (snapshot.hasData) {
final FirebaseUser user = snapshot.data;
if (user.displayName == null || user.displayName.isEmpty())
return text(currentUser.email); // display email if name isn't set
return text(currentUser.displayName);
}
if (snapshot.hasError) {
return text(snapshot.error);
}
return text('loading...');
},
),
If you want to have the displayName outside your build() function, the following code should do the job when you are inside of an async function:
final FirebaseUser user = await _auth.currentUser();
final String displayName = user.displayName;
print('the displayName of the current user is: $displayName');
And this code when you are in a normal function:
_auth.currentUser().then((FirebaseUser user) {
String displayName = user.displayName;
print('displayName: $displayName');
}).catchError((error) {
print('error: ' + error.toString());
});
I think it's worth watching the following video for further understanding:
Async/Await - Flutter in Focus