Flutter firebase logging in causes NoSuchMethodError - firebase

Question

I was following a tutorial to create an authentication system in flutter using firebase. Registration works as intended and the user is posted to my firebase database, however, when I try to login with the correct credentials, I get:
I/flutter (26424): user A a#a.com added
I/InputMethodManager(26424): showSoftInput
I/InputMethodManager(26424): mServedView =com.waifuhub.app;view =com.waifuhub.app;flags =0
I/HwSecImmHelper(26424): mSecurityInputMethodService is null
W/InputMethodManager(26424): startInputReason = 3
W/IInputConnectionWrapper(26424): getTextBeforeCursor on inactive InputConnection
W/IInputConnectionWrapper(26424): getSelectedText on inactive InputConnection
W/IInputConnectionWrapper(26424): getTextAfterCursor on inactive InputConnection
W/IInputConnectionWrapper(26424): requestCursorAnchorInfo on inactive InputConnection
I/InputMethodManager(26424): showSoftInput
I/InputMethodManager(26424): mServedView =com.waifuhub.app;view =com.waifuhub.app;flags =0
I/HwSecImmHelper(26424): mSecurityInputMethodService is null
W/InputMethodManager(26424): startInputReason = 3
V/AudioManager(26424): playSoundEffect effectType: 0
V/AudioManager(26424): querySoundEffectsEnabled...
I/HwSecImmHelper(26424): mSecurityInputMethodService is null
I/ViewRootImpl(26424): jank_removeInvalidNode all the node in jank list is out of time
I/flutter (26424): Sign In Error: NoSuchMethodError: The getter 'data' was called on null.
I/flutter (26424): Receiver: null
I/flutter (26424): Tried calling: data
Application finished.
Exited (sigterm)
The code responsible for signing in is as follows:
void _emailLogin(
{String email, String password, BuildContext context}) async {
if (_formKey.currentState.validate()) {
try {
SystemChannels.textInput.invokeMethod('TextInput.hide');
await _changeLoadingVisible();
//need await so it has chance to go through error if found.
await StateWidget.of(context).logInUser(email, password);
await Navigator.pushNamed(context, '/');
} catch (e) {
_changeLoadingVisible();
print("Sign In Error: $e");
String exception = Auth.getExceptionText(e);
Flushbar(
title: "Sign In Error",
message: exception,
duration: Duration(seconds: 5),
)..show(context);
}
} else {
setState(() => _autoValidate = true);
}
}
class StateWidget extends StatefulWidget {
final StateModel state;
final Widget child;
StateWidget({
#required this.child,
this.state,
});
// Returns data of the nearest widget _StateDataWidget
// in the widget tree.
static _StateWidgetState of(BuildContext context) {
return context.dependOnInheritedWidgetOfExactType<_StateDataWidget>().data;
}
#override
_StateWidgetState createState() => new _StateWidgetState();
}
class _StateWidgetState extends State<StateWidget> {
StateModel state;
//GoogleSignInAccount googleAccount;
//final GoogleSignIn googleSignIn = new GoogleSignIn();
#override
void initState() {
super.initState();
if (widget.state != null) {
state = widget.state;
} else {
state = new StateModel(isLoading: true);
initUser();
}
}
Future<Null> initUser() async {
//print('...initUser...');
FirebaseUser firebaseUserAuth = await Auth.getCurrentFirebaseUser();
User user = await Auth.getUserLocal();
Settings settings = await Auth.getSettingsLocal();
setState(() {
state.isLoading = false;
state.firebaseUserAuth = firebaseUserAuth;
state.user = user;
state.settings = settings;
});
}
Future<void> logOutUser() async {
await Auth.signOut();
FirebaseUser firebaseUserAuth = await Auth.getCurrentFirebaseUser();
setState(() {
state.user = null;
state.settings = null;
state.firebaseUserAuth = firebaseUserAuth;
});
}
Future<void> logInUser(email, password) async {
String userId = await Auth.signIn(email, password);
User user = await Auth.getUserFirestore(userId);
await Auth.storeUserLocal(user);
Settings settings = await Auth.getSettingsFirestore(userId);
await Auth.storeSettingsLocal(settings);
await initUser();
}
#override
Widget build(BuildContext context) {
return new _StateDataWidget(
data: this,
child: widget.child,
);
}
}
class _StateDataWidget extends InheritedWidget {
final _StateWidgetState data;
_StateDataWidget({
Key key,
#required Widget child,
#required this.data,
}) : super(key: key, child: child);
// Rebuild the widgets that inherit from this widget
// on every rebuild of _StateDataWidget:
#override
bool updateShouldNotify(_StateDataWidget old) => true;
}
static Future<String> signIn(String email, String password) async {
FirebaseUser user = (await FirebaseAuth.instance
.signInWithEmailAndPassword(email: email, password: password))
.user;
return user.uid;
}
class Validator {
static String validateEmail(String value) {
Pattern pattern = r'^[a-zA-Z0-9.]+#[a-zA-Z0-9]+\.[a-zA-Z]+';
RegExp regex = new RegExp(pattern);
if (!regex.hasMatch(value))
return 'Please enter a valid email address.';
else
return null;
}
static String validatePassword(String value) {
Pattern pattern = r'^.{6,}$';
RegExp regex = new RegExp(pattern);
if (!regex.hasMatch(value))
return 'Password must be at least 6 characters.';
else
return null;
}
static String validateName(String value) {
Pattern pattern = r"^[a-zA-Z]+(([',. -][a-zA-Z ])?[a-zA-Z]*)*$";
RegExp regex = new RegExp(pattern);
if (!regex.hasMatch(value))
return 'Please enter a name.';
else
return null;
}
static String validateNumber(String value) {
Pattern pattern = r'^\D?(\d{3})\D?\D?(\d{3})\D?(\d{4})$';
RegExp regex = new RegExp(pattern);
if (!regex.hasMatch(value))
return 'Please enter a number.';
else
return null;
}
}
And my dependencies in pubsec.yaml:
dependencies:
flutter:
sdk: flutter
flutter_launcher_icons: ^0.7.2
cupertino_icons: ^0.1.2
firebase_auth: ^0.15.5+3
cloud_firestore: ^0.13.4+2
flushbar: 1.9.1
shared_preferences: ^0.5.6+3
dev_dependencies:
flutter_test:
sdk: flutter
Upon further debugging, I think the error is due to the fact that null context is being passed to
_StateWidgetState, however, I am not sure if this is so, or how to solve this. Any help would be highly appreciated!

Answer 1

Not sure, but it seems you're missing calling
_formKey.currentState.save();
after calling _formKey.currentState.validate().
Otherwise this line is causing the error:
static _StateWidgetState of(BuildContext context) {
return (context.dependOnInheritedWidgetOfExactType() as _StateDataWidget)
.data;
}
This (context.dependOnInheritedWidgetOfExactType() as _StateDataWidget) is returning null
change it to:
return (context.inheritFromWidgetOfExactType(_StateDataWidget) as _StateDataWidget).data;
or
return context.dependOnInheritedWidgetOfExactType<_StateDataWidget>().data;