After creating the user in signup screen, I want to pass the user object to a new screen. But the user object is always null in the new screen though user creation is successful. I know current user can be accessed with FirebaseAuth.instance.currentUser() . But why is the user object null when it is passed from signup screen to a new screen?
Future<FirebaseUser> signUpUserWithEmailPass(
String email, String pass) async {
try {
var authResult = await firebaseAuth.createUserWithEmailAndPassword(
email: email,
password: pass,
);
print("On Try");
return authResult.user;
} on PlatformException catch (error) {
throw Exception(errors.toString());
}
}
Navigation to a new screen :
void navigateToHomePage(BuildContext context, FirebaseUser user) {
Navigator.push(context, MaterialPageRoute(builder: (context) {
return HomePage(user);
}));
}
Update : Solved
I am using BLoC pattern & I forgot to set user object in the state class's constructor. That's actually creating the problem!
It's null because it's asynchronous, the method signUpUserWithEmailPass returns a Future, then when you call it you can pass the result to the navigateToHomeScreen:
signUpUserWithEmailPass.then((result) => {
print(result);
navigateToHomePage(context,result);
});
This may be due to Asynchronous function. The user object could've been passed before you got the result.
So Kindly wait for signUpUserWithEmailPass() function complete first and then assign it to user object like this:
user = await signUpUserWithEmailPass("email", "password");
navigateToHomePage(context, user);
for this you have to make the parent function async.
Otherwise do this:
signUpUserWithEmailPass.then((user) {
navigateToHomePage(context, user);
});
Hope it helps
Related
I am using a Model class to authenticate user before registering or logging.the problem is that i don't know a way to print error message to the user in snackbar,because no widget is defined in this class.
How can i display error message to user from Model Class?
Model class:
class FireAuth {
static Future<User> registerUsingEmailPassword({
String name,
String email,
String password,
}) async {
FirebaseAuth auth = FirebaseAuth.instance;
User user;
try {
UserCredential userCredential = await auth.createUserWithEmailAndPassword(
email: email,
password: password,
);
user = userCredential.user;
await user.updateDisplayName(name);
await user.reload();
user = auth.currentUser;
//check if email is registered before
//add user data to firestore
CollectionReference users = FirebaseFirestore.instance.collection('users');
users.doc(user.uid).set({
'uid':user.uid,
'img_url':'0',
'name': name,
'phone': '',
'email': email,
'job_title':'',
'university':'',
'procedures':'',
'expert_in':'',
})
.then((value) => print("User Added"))
.catchError(
(error) => print("Failed to add user: $error"));
} on FirebaseAuthException catch (e) {
if (e.code == 'weak-password') {
print('The password provided is too weak.');
} else if (e.code == 'email-already-in-use') {
print('The account already exists for that email.');
}
} catch (e) {
print(e);
}
return user;
}
}
I need 'The account already exists for that email.' error message to display to user,not only printing it in log.
Excellent question, and I'll try to answer in the general so as to benefit your overall pattern in handling this very important case.
Depending on BuildContext is a common inconvenience in flutter. And it often comes up, but for good reason. You can think of it like this: You need the context because you need to specify where in the tree that UI is going to show. Knowing how to handle these cases makes the difference between beginner and more advanced flutter developers.
So one way is to pass the BuildContext around, but I wouldn't recommended it.
Lets say I have a function foo that returns some Future Rather than change the signature of the function to accept context, you can simply await the function and use the context in the callback already in your UI. For example,
instead of
Future foo(BuildContext context) {
try {
// await some async process
// Use context to show success.
} catch (e) {
// Use context to show failure.
}
}
You can do this
GestureDetector(
onTap: () async {
try {
await foo();
// Use context to show success.
} catch (e) {
// Use context to show failure.
}
},
child: // some child
),
The point is in the second example the context is already there in the widget. The signuture of foo is simpler. It requires some restructuring. Here I'm assuming that the series of events is traced back to a GestureDetector but it could be anything else.
I am trying to create a signup page which should give an error message if user with particular email id already exist. But it's not working.
signUp() {
if (formkey.currentState!.validate()) {
Map<String, String> userDataMap = {
"name": usernameC.text,
"email": emailC.text
};
setState(() {
isLoading = true;
});
authMethods.signUp(emailC.text, passwordC.text).then((value) {
databaseMethods.uploadUserData(userDataMap);
Navigator.pushReplacement(
context, MaterialPageRoute(builder: (context) => ChatRoom()));
});
}
}
It calls the signUp() function from auth.dart given below
UserData? _userFromFirebase(User? user) {
return user != null ? UserData(userid: user.uid) : null;
}
Future signUp(String email, String pass) async {
try {
UserCredential result = await _auth.createUserWithEmailAndPassword(
email: email, password: pass);
User? user = result.user;
return _userFromFirebase(user);
} catch (e) {
print(e}
}
Every time I signup with same email it doesn't give any error.
If you sign up with the same email you should get this message:
[firebase_auth/email-already-in-use] The email address is already in use by another account.
I use print(e.hashCode) and then use this hash code to show an error message.
Ok I tried this method and it worked out. Just added null check for the "value" attribute in.
authMethods.signUp(emailC.text, passwordC.text).then((value)
It was returning null without any other message. That's why I was unable to see the error.
I have a widget that uses a Future - async that returns a UserData variable, but for some reason, I'm getting a Future variable instead.
a line of code from a widget Build:
dynamic user = Auth.signIn(_email, _password);
Auth Class:
Future<UserData> signIn(String email, String password) async {
try{
UserCredential userCredential = await _auth.signInWithEmailAndPassword(
email: email,
password: password
);
print('signed in!');
return _createUserFromFirebase(userCredential.user.uid, null);
} on FirebaseAuthException catch (e) {
if (e.code == 'user-not-found') {
print('No user found for that email.');
} else if (e.code == 'wrong-password') {
print('Wrong password provided for that user.');
}
return null;
}
}
You could try something like
return Future.value(_createUserFromFirebase(userCredential.user.uid, null);
instead of
return _createUserFromFirebase(userCredential.user.uid, null);
Async cannot be used without it being in a function with await. You can't randomly retrieve an asynchronous variable randomly in the script without loading it asynchronously, because the future might not have the data ready to be used.
If you need the future variable's future value to be in a widget try using the FutureBuilder widget. This will make it so that the user data is loaded asynchronously and a place holder of your choice can be shown before it loads. This would allow you to use the UserData type in your widget.
Or you can get the user by having the button have an async variable that sets a variable in the widget from null to the UserData after signing in.
I've added a new future method inside the widget class that saves the user in a variable:
Future<void> getUserData(String email, String password) async{
_user = await _auth.signIn(email, password);
print('user: $_user');
}
I am learning Firebase with Flutter.
Currently making an anonymous login option, here is the class I created:
class AuthService {
final FirebaseAuth _auth = FirebaseAuth.instance;
// sign in anonymously
Future signInAnonymous() async {
try{
// signs in as anon user
AuthResult signInResult = await _auth.signInAnonymously();
// retruns currently signed in user, else null
FirebaseUser userFromResult = signInResult.user;
return userFromResult; // HERE: if I add .uid, the id object is displayed
}catch(e){
print(e.toString());
return null;
}
}
}
In my login page after creating an instance and using the method, when I print the result I get FirebaseUser(Instance of 'PlatformUser') insted of the user information, here is the code:
onPressed: () async {
dynamic result = await _auth.signInAnonymous();
if(result == null){print('Error signing in.');}
else{
print('Signed in successfully');
print(result);
}
How can I access the user data?
UPDATE: If I change return userFromResult; to return userFromResult.uid; the id string is returned.
I still wonder, however, how to print the full object.
Your Result inside of the onpressed is a dynamic type cast, but it is a FirebaseUser inside.
// onPressed Callback
dynamic result = await _auth.signInAnonymous();
You can change your SignIn method with the right return type and use instead of dynamic the FirebaseUser.
Future<FirebaseUser> signInAnonymous() async {
// [...]
return userFromResult; // HERE: if I add .uid, the id object is displayed
}
onPressed: () async {
FirebaseUser result = await _auth.signInAnonymous();
print(result.uid); // should contain the id
// [...]
The difference is that in version 0.13.x the user data is available, but in the version used in this example the bersion used is 0.16.x.
I'd like to block out people who didn't verify their email so i figured out this code for sign up:
// sign up
Future signUp(String email, String password) async {
try {
await _auth.createUserWithEmailAndPassword(
email: email, password: password);
} catch (e) {
print('An error has occured by creating a new user');
print(
e.toString(),
);
}
try {
final FirebaseUser _user = await _auth.currentUser();
await _user.sendEmailVerification();
} catch (error) {
print("An error occured while trying to send email verification");
print(error.toString());
}
try {
await _auth.signOut();
} catch (err) {
print(err);
}
}
and this for sign in:
//Sign In with Email and Pass
Future signInWithEmailAndPassword(String email, String password) async {
FirebaseUser _user = await FirebaseAuth.instance.currentUser();
if (_user != null && _user.isEmailVerified == true) {
try {
await _auth.signInWithEmailAndPassword(
email: email, password: password);
return _user;
} catch (e) {
return null;
}
} else {
return null;
}
}
_auth is just an instance of FirebaseAuth.
The problem is that i can login even if i didnt verify the email.
Firebase Auth doesn't stop accounts from signing in if the user hasn't verified their email address yet. You can check that property _user.isEmailVerified to find out the state of that validation after the user signs in, and you can determine from there what the user should see.
isEmailVerified can be a little bit of trouble to get working correctly.
Make sure you are calling
await FirebaseAuth.instance.currentUser()..reload();
before your are calling isEmailVerified also in my own experience and I don't know if this is just something I was doing wrong but this did not work from my Auth class this did not start working until I put the code directly in initState() of my widget that checks whether the user is verified. Like I said that part might have been something I did wrong. Like stated this will not listen for change you must check yourself either periodically or at a point that you know email is verified.
Future(() async {
_timer = Timer.periodic(Duration(seconds: 10), (timer) async {
await FirebaseAuth.instance.currentUser()
..reload();
var user = await FirebaseAuth.instance.currentUser();
if (user.isEmailVerified) {
timer.cancel();
Navigator.of(context).popAndPushNamed(HearingsScreen.routeName);
}
});
});
So it checks every 10 seconds to see if the user has verified their email not the most elegant solution. The page I have this on just displays a message 'Please verify your email' so its not like this is interrupting other code. If your app is performing other tasks this might not be an option for you. If you want to play around with isEmailVerified go ahead but i spent a week of headaches until i settled on this.