How to display the assigned card to only specific user in flutter - firebase

Question

I am creating a system that only certain user can see the list of the projects. The list of the projects will be shown in user application when the projects have been assigned to them thru administration by using user's email. I am using flutter and google firebase
I tried to use If else statement but I seem can't do it.
I have 2 model classes
User_model class
import 'package:firebase_auth/firebase_auth.dart';
class Users{
final String uid;
Users({this.uid});
}
class UserModel{
String uid;
String email;
String name;
String employeeID;
String phonenumber;
String position;
UserModel({this.uid, this.email, this.name, this.employeeID, this.phonenumber, this.position});
//receiving data from server
factory UserModel.fromMap(map){
return UserModel(
uid: map['uid'],
email: map['email'],
name: map['name'],
employeeID: map['employeeID'],
phonenumber: map['phonenumber'],
position: map['position'],
);
}
//sending data to our server
Map<String, dynamic> toMap(){
return{
'uid': uid,
'email': email,
'name' : name,
'employeeID' : employeeID,
'phonenumber' : phonenumber,
'position' : position,
};
}
}
class UserProject{
final String projectid;
final String address;
final String titleproject;
final List<String> assignedmember ;
UserProject({this.projectid, this.address, this.titleproject, this.assignedmember});
}
Project_model class
import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:firebase_auth/firebase_auth.dart';
import 'package:flutter/material.dart';
class Project{
final String address;
final String titleproject;
final List<dynamic> assignedmember;
Project({this.address, this.titleproject, this.assignedmember});
}
HomeScreen.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 'package:smartconstructionreport/data/project_model.dart';
import 'package:smartconstructionreport/data/user_model.dart';
import 'package:smartconstructionreport/screens/project_screen.dart';
import 'package:smartconstructionreport/theme.dart';
import 'package:smartconstructionreport/widget/ProjectCard.dart';
import 'package:smartconstructionreport/widget/menulist.dart';
import 'package:smartconstructionreport/service/database.dart';
import 'package:provider/provider.dart';
import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:smartconstructionreport/widget/projectlist.dart';
import 'FloorPlan.dart';
class HomeScreen extends StatefulWidget {
#override
State<HomeScreen> createState() => _HomeScreenState();
}
class _HomeScreenState extends State<HomeScreen> {
User user = FirebaseAuth.instance.currentUser;
UserModel loggedInUser = UserModel();
#override
void initState(){
super.initState();
FirebaseFirestore.instance
.collection("user")
.doc(user.uid)
.get()
.then((value){
this.loggedInUser = UserModel.fromMap(value.data());
setState(() {});
});
}
Widget build(BuildContext context) {
return StreamProvider<List<Project>>.value(
value: DatabaseService().projects,
child: Scaffold(
drawer: menulist(),
appBar: AppBar(
backgroundColor: kPrimaryColor,
centerTitle: true,
title: Image.asset('images/scdr logo.png',
fit: BoxFit.cover,),
),
body: SingleChildScrollView(
child: Padding(
padding: kDefaultPadding,
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
SizedBox(
height: 30,
),
Text(
"Hello ${loggedInUser.name},",
style: TextStyle(color: Colors.black,
fontSize: 25,
fontWeight: FontWeight.w700),
),
SizedBox(
height: 5,
),
Text(
'Have a great day ahead!',
style: TextStyle(color: Colors.black,
fontSize: 12,
),
),
SizedBox(
height: 5,
),
Text(
'Lets start working!',
style: TextStyle(color: Colors.black,
fontSize: 12,
),
),
SizedBox(
height: 30,
),
Text(
'Project Lists',
style: TextStyle(color: Colors.black,
fontSize: 25,
fontWeight: FontWeight.w700),
),
SizedBox(
height: 18,
),
ProjectList(),
],
),
),
),
),
);
}
}
ProjectList.dart
I tried to add If else statement to check if the project contains email assigned to the project. But it return null
import 'package:firebase_auth/firebase_auth.dart';
import 'package:flutter/material.dart';
import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:provider/provider.dart';
import 'package:smartconstructionreport/data/project_model.dart';
import 'package:smartconstructionreport/screens/project_screen.dart';
import 'ProjectCard.dart';
class ProjectList extends StatefulWidget {
#override
_ProjectListState createState() => _ProjectListState();
}
class _ProjectListState extends State<ProjectList> {
User user = FirebaseAuth.instance.currentUser;
Project projectmember = Project();
#override
Widget build(BuildContext context) {
final projects = Provider.of<List<Project>>(context) ?? [];
return ListView.builder(
shrinkWrap: true,
itemCount: projects.length,
itemBuilder: (context, index) {
if (projectmember.assignedmember.contains(user.email)) {
return ProjectCard(project: projects[index],
press: () {
Navigator.push(context, MaterialPageRoute(
builder: (context) => ProjectScreen(),
));
},
);
};
}
);
}
}
ProjectCard.dart
import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:smartconstructionreport/data/project_model.dart';
import 'package:smartconstructionreport/theme.dart';
class ProjectCard extends StatelessWidget {
final Function press;
final Project project;
ProjectCard({this.project, this.press});
#override
Widget build(BuildContext context) {
Size size = MediaQuery.of(context).size;
return GestureDetector(
onTap: press,
child: Card(
clipBehavior: Clip.antiAlias,
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(20.0)
),
elevation: 10,
margin: EdgeInsets.fromLTRB(5.0, 15.0, 5.0, 10.0),
child: Column(
children: [
Stack(
alignment: Alignment.center,
children: [
Padding(
padding: const EdgeInsets.all(2.0),
child: Text(
project.titleproject,
style: TextStyle(
fontSize: 17,
fontWeight: FontWeight.bold,
),
),
)
],
),
Divider(color: Colors.black),
Padding(
padding: EdgeInsets.fromLTRB(10.0, 5.0, 5.0, 0.0),
child: Text(
project.address,
style: TextStyle(fontSize: 14),),
),
Row(
children: [
Column(
children: [
TextButton.icon(
onPressed: (){},
icon: Icon(Icons.person,
color: kPrimaryColor,) ,
label: Text('Project Manager')),
],
),
SizedBox(width:50),
Column(
children: [
TextButton.icon(
onPressed: (){},
icon: Icon(Icons.location_pin,
color: kPrimaryColor,) ,
label: Text('MAP')),
],
)
],
),
],
),
),
);
}
}
Error
======== Exception caught by widgets library =======================================================
The method 'contains' was called on null.
Receiver: null
Tried calling: contains("rashid#fyp.com")
====================================================================================================