ChangeNotifierProvider can't seem to get List<String> - flutter

Question

I am using ChangeNotifierProvider to get a list of strings that i have read from Cloudfirestore. I know that the is okay because i print the legnth of my list to confirm. But somewhere in between the change notifier provider and my UI, I seem to get things lost. Someone help me understand this concept.
Here, i am setting the retrieved list:
class RestorationNetworkService {
static Future<List<String?>> getRepairProducts(RestorationNotifier restNot,) async {
final firebaseref = FirebaseFirestore.instance;
List<String?> repairproducts = [];
final data = await firebaseref.collection("restoration_products").get();
final datasetMap = data.docs.single.data();
repairproducts= (datasetMap['product'] as List).map((e) => e as String).toList();
print(repairproducts.length);
restNot.restoreProductList = repairproducts;
return repairproducts;
}
}
Here is my changeNotifier class:
import 'package:flutter/cupertino.dart';
class RestorationNotifier with ChangeNotifier {
List<String?> _repairproducts = [];
set restoreProductList(List<String?> repairproductlist) {
_repairproducts= repairproductlist;
notifyListeners();
}
List<String?> get repairProductList => _repairproducts;
}
Here i am trying to update my UI with the list:
#override
void initState() {
//lets load our future right here
RestorationNetworkService.getRepairProducts(rest);
super.initState();
}
#override
Widget build(BuildContext context) {
List<String?> restProdList = Provider.of<RestorationNotifier>(context, listen: false).repairProductList;
return Scaffold(
appBar: AppBar(
title: Text('Restore Furniture')
),
body: Center(
child: SafeArea(
child: SingleChildScrollView(
child: Column(
children: [
Wrap(
children: repairChips(restProdList),
),
],
),
)),
),
);
}
List<Widget> repairChips(List<String?> restoreProdList) {
List<Widget> chips = [];
int selectedIndex = 0;
for (int i = 0; i < restoreProdList.length; i++) {
Widget item = PhysicalModel(
clipBehavior: Clip.hardEdge,
color: Colors.transparent,
shadowColor: Colors.grey.withOpacity(0.3),
elevation: 10,
child: Padding(
padding: EdgeInsets.only(left: 10, right: 5),
child: ChoiceChip(
selected: selectedIndex == i,
selectedColor: Color(0xFFF7B239),
label: Text(restoreProdList[i] ?? ''),
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(2)),
backgroundColor: Colors.white,
onSelected: (bool value) {
setState(() {
selectedIndex = i;
});
},
)));
chips.add(item);
}
return chips;
}
}
I can't really seem to trace where exactly i am going wrong?

Answer 1

The list you get from Cloudfirestore not set to the state yet.
for current state in your app, the List<String?> = [ ];
you can modify your init function like below:
#override
void initState() {
// Fetch the data
fetchData();
super.initState();
}
Future<void> fetchData() async {
final state = context.read<RestorationNotifier>(); // initialize state provider
final result = await RestorationNetworkService.getRepairProducts(rest);
state.restoreProductList(result); // you miss this step. that assign the data to state
}
// this is my style using provider.
#override
Widget build(BuildContext context) {
final appState = context.watch<RestorationNetworkService>(); // we watching any change
return Scaffold(
appBar: AppBar(
title: Text('Restore Furniture')
),
body: Center(
child: SafeArea(
child: SingleChildScrollView(
child: Column(
children: [
// then you can access the object here.
Text('${appState.repairProductList.length}'), //
],
),
)),
),
);
}