How to call a function ASA the app runs in flutter? - firebase

Question

I have an application that do login with the help of firestore database and I want to do autologin so I made a boolean and set it to false in the database and made the login function set it to true as he or she sign in, so I want to check if the person have already signed in or not as the app runs, any ideas :) ?
here my code:
void getUserData() async {
try {
var firebaseUser = await FirebaseAuth.instance.currentUser();
firestoreInstance
.collection("Students")
.document(usernameController.text)
.get()
.then((value) {
setState(() {
email = (value.data)['email'];
password = (value.data)['password'];
gender = (value.data)['gender'];
loggedin = (value.data)['token'];
});
});
} catch (e) {
print(e.toString);
}
}

Answer 1

You dont have to use a boolean to check if the user is logged in or not. Firebase authentication already offers that. You can check inside the initState:
#override
void initState() {
super.initState();
FirebaseAuth.instance.currentUser().then((res) {
print(res);
if (res != null) {
Navigator.pushReplacement(
context,
MaterialPageRoute(builder: (context) => Home(uid: res.uid)),
);
}
else
{
Navigator.push(
context,
MaterialPageRoute(builder: (context) => SignUp()),
);
}
});
}
Checks if there is a current user or not and navigates to the required page.
If you have different types of users, then you have to identify them in the database. So authenticate in firebase authentication, and use a userType field in the database:
void registerToFb() {
firebaseAuth
.createUserWithEmailAndPassword(
email: emailController.text, password: passwordController.text)
.then((result) {
firestoreInstance.collection("users").document(result.user.uid).setData({
"email": emailController.text,
"name": nameController.text,
"userType" : "Students"
}).then((res) {
Navigator.pushReplacement(
context,
MaterialPageRoute(builder: (context) => Home(uid: result.user.uid)),
);
});
}).catchError((err) {
showDialog(
context: context,
builder: (BuildContext context) {
return AlertDialog(
title: Text("Error"),
content: Text(err.message),
actions: [
FlatButton(
child: Text("Ok"),
onPressed: () {
Navigator.of(context).pop();
},
)
],
);
});
});
}