我在互联网上四处寻找解决问题的方法，但找不到任何解决方案。我在Firestore中使用Flutter制作应用程序。我要这样做，以便当用户登录到顶部的应用程序时显示其名称（简单右侧）。我可以从Firestore获取数据：
Future<void> getName() async {
print("Attemping to get name!");
final firestoreInstance = await FirebaseFirestore.instance;
FirebaseAuth auth = FirebaseAuth.instance;
String uid = auth.currentUser.uid.toString();
await firestoreInstance.collection("Users").doc(uid).get().then((value) {
print("Name: " + value.data()["firstName"]);
info.firstName=((value.data()["firstName"]));
})
class info {
static String firstName;
}
但是它来得太晚了，因此该应用仅显示“欢迎回来” As you can see here，而不是“欢迎回来，康纳” As seen here
当我在控制台中查看时，该函数确实运行，但程序未等待它，并继续导致null。
谢谢
根据请求的用户界面代码进行编辑：
class Home extends StatelessWidget {
final DatabaseReference = FirebaseDatabase.instance;
final FirebaseAuth auth = FirebaseAuth.instance;
static String firstName;
static String lastName;
static String email;
static String companyName;
static bool isNewAccount = false;
static String name = "Welcome back";
Home();
@override
Widget build(BuildContext context) {
final User user = auth.currentUser;
final uid = user.uid;
final ref = DatabaseReference.reference();
if (isNewAccount == true) {
userSetup(firstName, lastName, email, companyName);
isNewAccount = false;
}
getName(); //does get the name from the database but name will error out as it doesn't get the name fast enough (or that's what I think)
name= "Welcome back, "+info.firstName;
return WillPopScope(
onWillPop: () async => false,
child: MaterialApp(
debugShowCheckedModeBanner: false,
home: Scaffold(
backgroundColor: Colors.cyan,
body: SingleChildScrollView(
child: Container(
margin:
EdgeInsets.only(top: MediaQuery.of(context).size.height / 16),
child: Column(
children: [
Container(
margin: EdgeInsets.only(bottom: 10),
child: Text(
name,
textAlign: TextAlign.center,
style: new TextStyle(
color: Colors.white,
fontSize: MediaQuery.of(context).size.width / 16,
),
),
),
Container(
width: 260,
height: 125,
child: RaisedButton(
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(20.0),
),
child: Text(
"CHECK-IN",
style: new TextStyle(
color: Colors.white,
fontSize: 40.0,
),
),
color: Colors.grey[850],
onPressed: () {
Navigator.push(context,
MaterialPageRoute(builder: (context) => Checkin()));
},
),
),
Container(
width: 260,
height: 140,
padding: EdgeInsets.only(top: 20),
child: RaisedButton(
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(20.0),
),
child: Text(
"CHECK-OUT",
style: new TextStyle(
color: Colors.white,
fontSize: 38.0,
),
),
color: Colors.grey[850],
onPressed: () {
Navigator.push(
context,
MaterialPageRoute(
builder: (context) => Checkout()));
},
),
),
Container(
margin: EdgeInsets.only(top: 55),
child: Row(
mainAxisAlignment: MainAxisAlignment.center,
children: [
Container(
padding: EdgeInsets.only(right: 20),
child: Text(
"Sign out: ",
style: new TextStyle(
fontSize: 15.0,
fontWeight: FontWeight.bold,
),
),
),
Container(
child: RaisedButton(
child: Text(
"SIGN OUT",
style: new TextStyle(
fontSize: 14.0,
color: Colors.white,
),
),
color: Colors.grey[700],
onPressed: () {
context.read<AuthenticationService>().signOut();
//return MyApp();
},
),
)
],
),
),
Container(
margin: EdgeInsets.only(top: 10),
child: Row(
mainAxisAlignment: MainAxisAlignment.center,
children: [
Container(
padding: EdgeInsets.only(right: 20),
child: Text(
"View Stats: ",
style: new TextStyle(
fontSize: 15.0,
fontWeight: FontWeight.bold,
),
),
),
Container(
child: RaisedButton(
child: Text(
"STATS",
style: new TextStyle(
fontSize: 14.0,
color: Colors.white,
),
),
color: Colors.grey[700],
onPressed: () {
Navigator.push(
context,
MaterialPageRoute(
builder: (context) => Stats()));
},
),
),
],
),
),
Container(
margin: EdgeInsets.only(top: 10),
child: Row(
mainAxisAlignment: MainAxisAlignment.center,
children: [
Container(
padding: EdgeInsets.only(right: 20),
child: Text(
"View Profile: ",
style: new TextStyle(
fontSize: 15.0,
fontWeight: FontWeight.bold,
),
),
),
Container(
child: RaisedButton(
child: Text(
"PROFILE",
style: new TextStyle(
fontSize: 14.0,
color: Colors.white,
),
),
color: Colors.grey[700],
onPressed: () {
/*Navigator.push(
context,
MaterialPageRoute(
builder: (context) => Stats()));*/
},
),
),
],
),
),
Container(
width: 240,
height: 55,
margin: EdgeInsets.only(
top: MediaQuery.of(context).size.height / 12),
child: RaisedButton(
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(20.0),
),
child: Text(
"EMERGENCY REPORT",
style: new TextStyle(
color: Colors.white,
fontSize: 20.0,
),
),
color: Colors.grey[700],
onPressed: () {
Navigator.push(context,
MaterialPageRoute(builder: (context) => EmergencyReport()));
},
),
),
],
),
),
),
),
),
);
}
static getAccountDetails(
String firstName1, String lastName1, String email1, String companyName1) {
firstName = firstName1;
lastName = lastName1;
email = email1;
companyName = companyName1;
isNewAccount = true;
}
static getFirstName(String nameFirst) {
name = "Welcome back, "+nameFirst;
}
}
答案 0 :(得分：0)
您需要将StatelessWidget转换为StatefullWidget。 之后，您必须在initState方法中编写此代码
void initState() {
super.initState();
getName().then((){
setState(() {
name= "Welcome back, "+info.firstName;
});
});
}
答案 1 :(得分：0)
FutureBuilder<DocumentSnapshot>(
future: firestoreInstance.collection("Users").doc(uid).get(),
builder: (_,snap){
return snap.hasData ? Text(snap.data.data()["firstName"]):CircularProgressIndicator();
},)