Firebase List view is not displayed in real-time while adding data - firebase

Question

I am storing Contact information on Firebase real-time DB after picking a contact from the phone.
When I add the data which is displayed using ListView and DataSnapshot the data is not refreshed in real-time until I restart the Activity. The ListView loads and displays all the data without any problem. How do I resolve this issue?
My screen looks like this:
Code for Screen:
import 'package:epicare/CaregiverClass.dart';
import 'package:epicare/Homepage.dart';
import 'package:firebase_auth/firebase_auth.dart';
import 'package:firebase_database/firebase_database.dart';
import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:flutter_switch/flutter_switch.dart';
import 'package:permission_handler/permission_handler.dart';
import 'package:contact_picker/contact_picker.dart';
//Check contacts permission
Future<PermissionStatus> _getPermission() async {
final PermissionStatus permission = await Permission.contacts.status;
if (permission != PermissionStatus.granted &&
permission != PermissionStatus.denied) {
final Map<Permission, PermissionStatus> permissionStatus =
await [Permission.contacts].request();
return permissionStatus[Permission.contacts] ??
PermissionStatus.undetermined;
} else {
return permission;
}
}
class CaregiverScreen extends StatefulWidget {
#override
_CaregiverScreenState createState() => _CaregiverScreenState();
}
class _CaregiverScreenState extends State<CaregiverScreen> {
//Firebase
FirebaseAuth firebaseAuth = FirebaseAuth.instance;
final ref = FirebaseDatabase.instance.reference();
User cuser = FirebaseAuth.instance.currentUser;
final fb = FirebaseDatabase.instance.reference().child("User_data");
List <CaregiverList> list = List();
// Adding data into Firebase
void addData(String name, String number) {
print("Saving data to firebase");
ref.child('User_data').child(cuser.uid).child("caregivers").push().set({'Caregiver_Name': name, 'Caregiver_Number': number});
}
// Get location
Position _currentPosition;
String _currentAddress;
final Geolocator geolocator = Geolocator()..forceAndroidLocationManager;
#override
void initState() {
// Firebase
fb.child(cuser.uid).child("caregivers").once().then((DataSnapshot snapshot)
{
var data = snapshot.value;
list.clear();
data.forEach((key,value){
print(value['Caregiver_Name']);
CaregiverList contact_list = new CaregiverList(
name: value['Caregiver_Name'],
phone_number: value['Caregiver_Number'],
isActive: true,
key: key,
);
list.add(contact_list);
});
setState(() {
});
}
);
super.initState();
}
final ContactPicker _contactPicker = new ContactPicker();
final GlobalKey<ScaffoldState> _scaffoldKey = new GlobalKey<ScaffoldState>();
#override
Widget build(BuildContext context) {
//Size size = MediaQuery.of(context).size;
return Scaffold(
key: _scaffoldKey,
backgroundColor: Colors.white,
appBar: AppBar(
backgroundColor: const Color(0xffE5E0A1),
elevation: 0,
centerTitle: true,
title: Text(
"Add Caregiver",
style: TextStyle(
fontSize: 15.0,
color: Colors.black,
fontFamily: 'Montserrat',
fontWeight: FontWeight.normal,
),
),
leading: IconButton(
icon: Icon(
Icons.arrow_back,
color: Colors.black,
),
onPressed: () {
Navigator.push(
context,
MaterialPageRoute(
builder: (context) {
return Homepage();
},
),
);
},
),
),
body: SingleChildScrollView(
child: Container(
padding: EdgeInsets.symmetric(horizontal: 10, vertical: 40),
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
Row(
children: [
MaterialButton(
onPressed: () async {
final PermissionStatus permissionStatus =
await _getPermission();
if (permissionStatus == PermissionStatus.granted) {
//We can now access our contacts here
Contact contact = await _contactPicker.selectContact();
print("Contact name: ${contact.fullName}");
print("Contact number: ${contact.phoneNumber}");
List<String> num =
contact.phoneNumber.toString().split('(Work)');
print(num);
print(num[0]);
final pattern = RegExp('\\s+');
num[0].replaceAll(pattern, '');
num[0].replaceAll(new RegExp('-'),'');
addData(contact.fullName.toString(),num[0]);
} else {
//If permissions have been denied show standard cupertino alert dialog
showDialog(
context: context,
builder: (BuildContext context) =>
CupertinoAlertDialog(
title: Text('Permissions error'),
content: Text('Please enable contacts access '
'permission in system settings'),
actions: <Widget>[
CupertinoDialogAction(
child: Text('OK'),
onPressed: () =>
Navigator.of(context).pop(),
)
],
));
}
},
color: const Color(0xffd4d411),
textColor: Colors.white,
child: Icon(
Icons.add,
size: 32,
),
padding: EdgeInsets.all(3),
shape: CircleBorder(),
),
Text(
'Add a Caregiver',
style: TextStyle(
fontFamily: 'Montserrat',
fontSize: 13,
color: const Color(0xff000000),
height: 1.5384615384615385,
fontWeight: FontWeight.w600),
textHeightBehavior:
TextHeightBehavior(applyHeightToFirstAscent: false),
textAlign: TextAlign.left,
)
],
),
list.length == 0 ? Center(child: Text("Please add Caregivers"))
: ListView.separated(
physics: NeverScrollableScrollPhysics(),
shrinkWrap: true,
primary: false,
itemBuilder: (context, index) {
return _caregiverWidget(list[index].name,list[index].phone_number,list[index].isActive,list[index].key
);
},
separatorBuilder: (_, __) => Container(),
itemCount: list.length),
// _contact == null ? Container() : CaregiversList(_contact.fullName),
],
),
),
),
);
}
Widget _caregiverWidget( String name, String phone_number, bool isActive, String key
) {
print(name);
var c = name.split(' ');
print(c[0]);
var caregiver = c[0];
var output = getInitials(string: caregiver, limitTo: 1);
print(output);
return GestureDetector(
onLongPress: (){},
onTap: (){},
child: Card(
elevation: 0,
child: Container(
padding: EdgeInsets.symmetric(vertical: 10, horizontal: 27),
child: Row(
//crossAxisAlignment: CrossAxisAlignment.center,
//mainAxisAlignment: MainAxisAlignment.spaceBetween,
children: <Widget>[
CircleAvatar(
radius: 24,
backgroundColor: const Color(0xffd4d411),
child: CircleAvatar(
radius: 22,
backgroundColor: Colors.white,
child: Text(
output,
style: TextStyle(
fontFamily: 'Segoe UI',
fontSize: 20,
color: const Color(0xff000000),
),
),
),
),
SizedBox(width: 19),
Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
Text(
caregiver,
style: TextStyle(
fontFamily: 'Montserrat',
fontSize: 13,
color: const Color(0xff000000),
height: 1.5384615384615385,
fontWeight: FontWeight.w600),
textHeightBehavior:
TextHeightBehavior(applyHeightToFirstAscent: false),
textAlign: TextAlign.left,
),
isActive
? Text(
"Activated",
style: TextStyle(
fontFamily: 'Montserrat',
fontSize: 10,
color: const Color(0x80232425),
fontWeight: FontWeight.w500),
textAlign: TextAlign.left,
)
: Text(
"Disabled",
style: TextStyle(
fontFamily: 'Montserrat',
fontSize: 10,
color: const Color(0x80232425),
fontWeight: FontWeight.w500),
textAlign: TextAlign.left,
),
],
),
SizedBox(width: 143),
FlutterSwitch(
width: 40.0,
height: 20.0,
value: isActive,
toggleSize: 15,
borderRadius: 40.0,
padding: 2.0,
showOnOff: false,
activeColor: const Color(0xffd4d411),
activeToggleColor: Colors.white,
inactiveColor: const Color(0xffDDDBAF),
inactiveToggleColor: Colors.white,
onToggle: (value) {
print(value);
setState(() {
isActive = value;
// _careList.removeAt(index);
// _careList.insert(index, _caregiver);
});
},
),
],
),
),
),
);
}
String getInitials({String string, int limitTo}) {
var buffer = StringBuffer();
var split = string.split(' ');
for (var i = 0; i < (limitTo ?? split.length); i++) {
buffer.write(split[i][0]);
}
return buffer.toString();
}
}

Answer 1

The issue is that this part:
fb.child(cuser.uid).child("caregivers").once()..
is only getting the value once.
To se realtime updates you should either use a listener like here:
CollectionReference reference = Firestore.instance.collection('caregivers');
reference.snapshots().listen((querySnapshot) {
querySnapshot.documentChanges.forEach((change) {
// Do something with change
});
});
or a StreamBuilder like here:
StreamBuilder<QuerySnapshot>(
stream: Firestore.instance.collection('caregivers').snapshots(),
builder: (BuildContext context, AsyncSnapshot<QuerySnapshot> snapshot) {
if (!snapshot.hasData) return new Text('Loading...');
return new ListView(
children: snapshot.data.documents.map((DocumentSnapshot document) {
return new ListTile(
title: new Text(document['name']),
);
}).toList(),
);
},
);
for the RTDB the StreamBuilder would look like this:
StreamBuilder(
stream: _database.reference().child('caregivers').onValue,
builder: (context, event) {
if (event.hasData &&
!event.hasError &&
event.data.snapshot.value != null) {
DataSnapshot snapshot = event.data.snapshot;
}
})
the listener would be like:
_database.reference().child('caregivers').onValue.listen((event){
})
onValue will give you everytime the whole list so you need to empty it before you add again every item:
var data = event.snapshot.value;
list= List(); //Clear the list here
data.forEach((key, value) {
print(value['Caregiver_Name']);
CaregiverList contact_list = new CaregiverList(
name: value['Caregiver_Name'],
phone_number: value['Caregiver_Number'],
isActive: true,
key: key,
);
list.add(contact_list);
});