HTTP GET Request with Provider doesnt work - flutter

Question

so I have a GET request that needs authorization headers, and I've tried using Postman manually where it works just fine, but not in my Dart code.
So I have this announcements.dart Provider class:
class Announcements with ChangeNotifier {
List _items = [];
String? token;
// late Future<Announcement> futureAnnouncement;
Announcements(this.token, this._items);
List get items {
return [..._items];
}
Future<void> fetchAnnouncements() async {
String url = "https://api-staging.xxx.us.org/1.0/announcements";
try {
final response = await http.get(
Uri.parse(url),
headers: {HttpHeaders.authorizationHeader: token!},
);
final extractedData = json.decode(response.body);
final List loadedProducts = [];
extractedData.forEach((prodId, data) {
loadedProducts.add(
Announcement(id: prodId, title: data['title'], body: data['body']));
});
print(response);
_items = loadedProducts;
print(_items);
notifyListeners();
} catch (e) {
throw (e);
}
and this is my main.dart function where the ChangeNotifier works:
class _MyAppState extends State<MyApp> {
#override
Widget build(BuildContext context) {
return MultiProvider(
providers: [
ChangeNotifierProvider.value(
value: Auth(),
),
ChangeNotifierProxyProvider<Auth, Announcements>(
create: (_) => Announcements(null, []),
update: (_, auth, previousProducts) => Announcements(
auth.token,
previousProducts == null ? [] : previousProducts.items,
),
),
],
child: Consumer<Auth>(
builder: (ctx, auth, _) => MaterialApp(
title: 'Xxx',
theme: ThemeData(),
home: NavigationScreen(),
),
),
);
}
}
This is how the announcement is called:
class AnnouncementScreen extends StatelessWidget {
#override
Widget build(BuildContext context) {
final announcementData = Provider.of<Announcements>(context);
return Scaffold(
backgroundColor: Color(0xff1e1e1e),
body: SafeArea(
child: Padding(
padding: const EdgeInsets.all(8.0),
child: Column(
children: [
SizedBox(
height: 90,
),
Text(
'Good Morning, John',
style: TextStyle(
fontSize: 32,
fontFamily: 'Casper',
color: Color.fromRGBO(247, 245, 232, 1),
),
),
SizedBox(
height: 10,
),
Expanded(
child: SizedBox(
height: 200.0,
child: FutureBuilder(
future: Provider.of<Announcements>(context)
.fetchAnnouncements(),
builder: (ctx, snapshot) => snapshot.connectionState ==
ConnectionState.waiting
? Center(child: CircularProgressIndicator())
: ListView.builder(
itemCount: announcementData.items.length,
itemBuilder: (context, index) {
return Column(
children: [
_tile(announcementData.items[index].title,
announcementData.items[index].body),
Divider(
thickness: 4,
indent: 0,
endIndent:
MediaQuery.of(context).size.width / 1.4,
color: Color.fromRGBO(198, 158, 96, 1),
),
],
);
}),
),
),
),
],
),
),
),
);
}
}
Thanks for helping, really appreciate it!

Answer 1

There are certain things you need to change, I don't know exactly what's the problem in this code.
I think the fetching is happening but the widget rebuilds so many times, which makes the future be fetched every time the rebuild happens, which again trigger the rebuild
Change the Widget to StatefulWidget
Extract the fields inside didChangeDependencies (since you need context)
class AnnouncementScreen extends StatefulWidget {
#override
_AnnouncementScreenState createState() => _AnnouncementScreenState();
}
class _AnnouncementScreenState extends State<AnnouncementScreen > {
late final announcementFuture;
late final Announcements announcement;
bool isInitialised = false;
#override
void didChangeDependencies() {
super.didChangeDependencies();
if(!isInitialised ){
announcement = Provider.of<Announcements>(context);
announcementFuture = announcement.fetchAnnouncements();
isInitialised = true;
}
}
#override
Widget build(BuildContext context) {
return ....(
FutureBuilder(
future:announcementFuture ,
builder: (ctx,snapshot){
//code
}
),
...
);
}
}

Answer 2

Have you checked if the auth token is loaded in your project?
It may be easier to debug this if you create a simple Dart command line app that makes the calls you need. Then you can do something like:
void main() async {
try {
final auth = Auth();
final token = auth.whateverMethodGetsToken();
// Note: Announcements class shouldn't really need ChangeNotifier
final announcements = Announcements(token, []);
final result = announcements.fetchAnnouncements();
print(result);
} catch (e) {
print(e);
}
}
This will tell you if the problem is in your networking code and make it easier to debug it.