I am trying to do autologin with flutter and firebase and put it in an initState but it doesn't seem to be excuted because I tried to move it to Build Widget but nothing worked but when I put it inside LoginPageState It was excuted but with error :
Navigator operation requested with a context that does not include a Navigator.
My Code :
#override
void initState() {
super.initState();
final user = FirebaseAuth.instance.currentUser();
if (user == null) {
print('User Null');
} else {
Navigator.pushReplacementNamed(context, '/HomePage');
}
}
You need to wait for the FirebaseAuth.instance.currentUser() to finish. So use await as the following.
final user = await FirebaseAuth.instance.currentUser()
Related
I'm using Shared preferences to save the user's name and login state even after closing the app. the Shared Preference I used in main.dart is fine because I used it in the main function and made it async, but when I'm trying to use it in other classes, I see a dark red screen for less than a second before loading the page and it makes my app so ugly. what can I do to fix it?
Here's my code:
late bool _isEditingText;
TextEditingController _editingController = TextEditingController();
late String initialText ;
SharedPreferences? _prefs;
#override
void initState(){
super.initState();
initializePreference().whenComplete((){
setState(() {});
});
}
Future<void> initializePreference() async{
_prefs = await SharedPreferences.getInstance();
String? name = _prefs?.getString('name');
if (name == null) {
_isEditingText = true;
initialText = 'Enter ur name';
} else {
_isEditingText = false;
initialText = name;
}
}
Update:
sorry for not including my exact error... here it is :
LateInitializationError: Field '_isEditingText#37486951' has not been initialized.
I think you are performing setState before all widgets are get initialised. So for that you can update initState as below:
void initState(){
super.initState();
WidgetsBinding.instance!.addPostFrameCallback((_) async {
initializePreference().whenComplete((){
setState(() {});
});
});
}
If it's not causing issue, than you have to show loading indicator. Like initially when there is no data indicator will be there and once you get data from SharedPreference in setState - you have to remove indicator and load your data.
You can use CircularProgressIndicator for that.
initialise your boolean variable,
var isDataLoad = false;
once you get data in whenComplete(), set it as true and based on this variable you can declare your widgets.
isDataLoad ? Container( // Your widgets where you use "initialText" ) : CircularProgressIndicator();
I am trying to update the home of MaterialApp widget depending on whether the user has sign up or not.
Below is the code inside the state of ``MaterialApp```
String? _userUid;
#override
void initState() {
FirebaseAuth.instance.authStateChanges().listen((user) {
//print('changed');
print(user?.uid);
updateUser(user?.uid);
});
super.initState();
}
void updateUser(String? USER_UID) {
setState(() {
_userUid = USER_UID;
});
}
Below is the code for the home property
home: _userUid == null ? const Onbaording2() : const HomeScreen(),
Somewhere inside the widget tree
final user = await _firebaseAuth.createUserWithEmailAndPassword(
email: email!,
password: password!,
);
After running the code above, there is a user created in firebase but the screen does not change.
Also the signOut works perfectly by signing me out when I use firebaseAuth.instance.signOut();
even if you change your variable it will not be redirected to the home screen because materialapp is only called when you first load or restart the app so rather than adding this condtion in home page or other way can be
#override
void initState() {
FirebaseAuth.instance.authStateChanges().listen((user) {
//print('changed');
print(user?.uid);
if(user == null){ navigate to onboarding }
else{ navigate to home page }
});
super.initState();
}
You can see the strange behaviour in this video: https://streamable.com/r5ld2y
The InitValue is the correct one, but when I restart the App it first goes to zero, AFTER loading the Screen OR press a button, it loads the shared prefs...
This is my Cubit (Only with the LoadCounter Func):
class DrinkCubit extends Cubit<DrinkState> {
DrinkCubit() : super(DrinkState(drinkValue: 0));
Future<void> loadCounter() async {
final prefs = await SharedPreferences.getInstance();
state.drinkValue = (prefs.getInt('counter') ?? 0);
}
}
And this is my InitFunction in the main window!
#override
void initState() {
super.initState();
Future.delayed(Duration.zero,()
{
BlocProvider.of<DrinkCubit>(context).loadCounter();
});
}
So how do I fix this, that the correct value is directly after starting the app showed
Try this:
getData(){
BlocProvider.of<DrinkCubit>(context).loadCounter();
}
#override
void initState() {
SchedulerBinding.instance.addPostFrameCallback((_) {
getData();
});
super.initState();
}
SchedulerBinding.instance.addPostFrameCallback ensures that code inside run before UI code.
And if it allows me to give you a hint, is better remove SharedPreferences of your Bloc and put in another class.
This is my controller.dart file which checks if users is verified or not and then return the page according to the conditions.
My question is that why the build widget is executing first before initState() ? I tried to debug this code using breakpoints and noticed that build() widget is running first and then the initState()Why this is happening and how could I fix it ?
This is my code :
class _ControllerState extends State<Controller> {
late bool auth;
#override
Widget build(BuildContext context) {
return (auth==false) ? Onbording() : IndexPage();
}
#override
void initState() {
super.initState();
WidgetsBinding.instance!.addPostFrameCallback((_) async {
await this.checked_if_logged();
});
}
Future<void> checked_if_logged() async {
SharedPreferences prefs = await SharedPreferences.getInstance();
if(prefs.getBool('verified')==true){
setState(() {
auth = true;
});
}else{
setState(() {
auth = false;
});
}
}
}
This is a snapshot of my debug code where the blue line is showing that it runs first before init and because the bool auth is a late type so it throws lateInitializationErrror and after that initState() is called which initializes the auth variable which rebuild the widget and removes the error
Update:
I noticed that when I replace the WidgetsBinding.instance!.addPostFrameCallback((_) with just check_if_logged(), the initState() is calling first but before completion of check_if_logged() the build widget executes first which again throws lateInitializationError
I don't know where you got addPostFrameCallback from or what you want to achieve, but this is not the way.
Your problem is, that checked_if_logged is async and there is no way to await an async method in initState. That is by design and there is no way around that.
The proper way to handle this is to use a FutureBuilder widget.
See What is a Future and how do I use it?
I'm building a Flutter app, and have a page with a table that is populated with data. I load the data like so:
class _AccountMenuState extends State<AccountMenu> { {
List<Account> accounts;
Future<List<Account>> getAccounts() async {
final response = await http.get('http://localhost:5000/accounts/' + globals.userId);
return jsonDecode(response);
}
setAccounts() async {
accounts = await getAccounts();
}
#override
void initState() {
setAccounts();
super.initState();
}
}
This works as expected when hot reloading the page, but when I route to this page via MaterialPageRoute,
like so: Navigator.push(context, MaterialPageRoute(builder: (context) => AccountMenu()));
then the data is not there.
What am I missing? I thought initState() gets called whenever a page loads?
You cannot do setState inside initState directly but you can wrap the initialization inside a PostFrameCallback to make sure that the initState lifecycle of the Widget is done.
class _AccountMenuState extends State<AccountMenu> { {
List<Account> accounts;
Future<List<Account>> getAccounts() async {
final response = await http.get('http://localhost:5000/accounts/' + globals.userId);
return jsonDecode(response);
}
setAccounts() async {
accounts = await getAccounts();
setState(() {})
}
#override
void initState() {
WidgetsBinding.instance.addPostFrameCallback((_) => setAccounts());
super.initState();
}
}
initState() will not wait for setAccounts() to finish execution. In the method setAccounts() call setState after loading data.
setAccounts() async {
accounts = await getAccounts();
setState((){});
}
initState does not await. It only loads functions before the widget builder but it does not await.
you need to await loading widgets with data until accounts.length is not empty.
Show loading widget while data still loads or use FutureBuilder
List<Account> accounts;
#override
void initState() {
setAccounts();
super.initState();
}
#override
Widget build(BuildContext context) {
accounts.length > 0 ? SHOW_DATA_HERE : LOADING_WIDGET_HERE
}