How to pass data between classes? Flutter - firebase

Question

I have a class which I get email data from the user. It's basicly a textfield so I wont post the textfield code. After I get the email and password data, I check if these data is in my Firestore database. If it is, I want to pass this email data to my other class which I get the other informations about customer.
Here is the code of trying to check if user exists when I click the button.This is my LoginScreen() class' Material Button's onPressed action. I only get the email from the user here and want to pass this email data to my CustomerInfo class if the user already exists in my FirebaseAuth.Also the CustomerScreen class is for the show all customer information on the screen. I will add some code to push the customer information after I successfully get the data form database.
try {
final user = await _auth.signInWithEmailAndPassword(
email: email!, password: password!);
if (user != null) {
CustomerInfo(email: email);
Navigator.push(
context,
MaterialPageRoute(
builder: (context) => CustomerScreen()));
}
} catch (e) {
print(e);
}
Also I have another class which I'm trying to get customers data.
class CustomerInfo {
String? email;
String? name;
String? surname;
String? avatarLink;
int? balance;
CollectionReference customers =
FirebaseFirestore.instance.collection('customers');
CustomerInfo({this.email});
Future getCustomerData() async {
print("Email: $email");
await customers.where('email', isEqualTo: email).get().then((value) {
value.docs.forEach((result) {
name = result['name'];
surname = result['surname'];
balance = result['balance'];
avatarLink = result['image'];
});
});
}
}
Also CustomerInfo class:
import 'package:banking_app_firebase/constants.dart';
import 'package:banking_app_firebase/networking.dart';
import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:firebase_auth/firebase_auth.dart';
import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'login_screen.dart';
class CustomerScreen extends StatefulWidget {
const CustomerScreen({Key? key}) : super(key: key);
#override
_CustomerScreenState createState() => _CustomerScreenState();
}
class _CustomerScreenState extends State<CustomerScreen> {
String? name;
String? surname;
int? balance;
String? image;
void getData() async {
CustomerInfo customerInfo = CustomerInfo();
await customerInfo.getCustomerData();
name = customerInfo.name;
print("Name: $name");
}
#override
void initState() {
// TODO: implement initState
super.initState();
getData();
}
#override
Widget build(BuildContext context) {
return Scaffold(
backgroundColor: Colors.white,
appBar: AppBar(
backgroundColor: Colors.white,
iconTheme: IconThemeData(
color: Colors.black,
),
title: Text(
"Account Summary",
style: TextStyle(
fontSize: 20,
fontWeight: FontWeight.bold,
color: Colors.black,
),
),
actions: [
Container(
padding: EdgeInsets.only(right: 10),
child: Row(
children: [
Icon(
CupertinoIcons.bell,
color: Colors.black,
),
SizedBox(
width: 10,
),
CircleAvatar(
backgroundImage: NetworkImage(
"https://cdn.pixabay.com/photo/2016/03/23/04/01/woman-1274056_960_720.jpg"),
),
],
),
),
],
elevation: 0,
),
body: Container(
child: Column(
children: [
Align(
alignment: Alignment.topLeft,
child: Text(
"Deneme",
style: kInfoTextDecoration,
),
),
Align(
alignment: Alignment.topLeft,
child: Text(
"Deneme",
style: kInfoTextDecoration,
),
),
],
),
),
);
}
}
How can I pass the email data to my CustomerInfo class so I can use getCustomerData()? Using CustomerInfo(email:email) did not work.

Answer 1

I am sorry, I think I misunderstood your question.
Is this what you are trying to do? You are passing email correctly. You just need to call getCustomerData()
try {
final user = await _auth.signInWithEmailAndPassword(
email: email!, password: password!);
if (user != null) {
var customerInfo = CustomerInfo(email: email);
await customerInfo.getCustomerData();
Navigator.push(
context,
MaterialPageRoute(
builder: (context) => CustomerScreen(customerInfo: customerInfo)));
}
} catch (e) {
print(e);
}
Then in CustomerScreen it would look like this
class CustomerScreen extends StatefulWidget {
final CustomerInfo customerInfo;
const CustomerScreen({Key? key, this.customerInfo}) : super(key: key);
#override
_CustomerScreenState createState() => _CustomerScreenState();
}
class _CustomerScreenState extends State<CustomerScreen> {
String? name;
String? surname;
int? balance;
String? image;
void getData() {
name = widget.customerInfo.name;
surname = widget.customerInfo.surname;
balance = widget.customerInfo.balance;
image = widget.customerInfo.image;
}
But I would recommend you take a look into FutureBuilder.

Answer 2

this will not work as the email field is not static so you can't use CustomerInfo.getCustomerData(). You need to create an instance of custom user and then use the getCustomerData() method.
For example: var data = await CustomerInfo(email: email).getCustomerData();
or if you are going to use the CustomerInfo()` multiple times you can do the following:
final CustomerInfo info = CustomerInfo(email: email);
var data = info.getCustomerData();
or something similar to that.
If you are trying to display the info inside of the CustomScreen() I think it might be easier to just create a CustomerInfo() there and get whatever data you need.
All I can do is guess as you haven't provided a sample for CustomScreen() or what it is meant to do. If you are trying to the customer data in the CustomScreen() then it might be better to use a FutureBuilder() to show your user that the data is loading then display it once the future completes rather than just having an async callback before pushing the route making the user think that they didn't click the button.

Answer 3

It depends on your preferences. For example, usually, I create a global.dart and store temporary variables there. for example in your global.dart:
CustomerInfo selectedUser;
then you can set it wherever you want. for example:
import './global.dart' as global;
try {
final user = await _auth.signInWithEmailAndPassword(
email: email!, password: password!);
if (user != null) {
CustomerInfo(email: email);
global.selectedUser = CustomeInfo(SET PARAMETERS);
Navigator.push(
context,
MaterialPageRoute(
builder: (context) => CustomerScreen()));
}
} catch (e) {
print(e);
}
the you can use it by calling global.selectedUser wherever you want.
Other approach is using Provider but it is useful when you want to change the variable in many files.
Also, you can use firebase methods for getting active user and his/her info like getEmail() but I do not recommend it because of unnecessary API call.

Answer 4

Get the email info from _auth.
try {
final user = await _auth!.signInWithEmailAndPassword(
email: email!, password: password!);
if (user.user !=null) { // added user.user
CustomerInfo(email: user.user!.email); //added user.user!.email
Navigator.push(
context,
MaterialPageRoute(
builder: (context) => CustomerScreen()));
}
} catch (e) {
print(e);
}