Flutter : Why is my builder not getting reloaded after web service call? - api

Question

I have written the web service call and is being called in the initState() method. A CircularProgressIndicator() is being called if there is no data available. But the progress indicator keeps on rotating even though the web service call is over!
After making a service call, why is my builder not getting reloaded?
I am new to flutter!! Am I going wrong anywhere?
class _DashboardState extends State<Dashboard> {
bool isLoading = false;
Future<List<OrganizationModel>> fetchOrganizationData() async {
isLoading = true;
var response = await http.get(organizationAPI);
if (response.statusCode == 200) {
final items = json.decode(response.body).cast<Map<String, dynamic>>();
orgModelList = items.map<OrganizationModel>((json) {
return OrganizationModel.fromJson(json);
}).toList();
isLoading = false;
return orgModelList;
} else {
isLoading = false;
throw Exception('Failed to load internet');
}
}
#override
void initState() {
this.fetchOrganizationData();
super.initState();
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text("Dashboard"),
),
body: Container(
decoration: BoxDecoration(
gradient: LinearGradient(
begin: Alignment.topCenter,
end: Alignment.bottomCenter,
colors: [Color(0xFF076A72), Color(0xFF64B672)])),
child: Column(
children: <Widget>[
Container(
color: Color(0xFF34A086),
height: 1,
),
isLoading ? loadProgressIndicator() : Expanded(
child: Padding(
padding: const EdgeInsets.only(left: 40, right: 40),
child: ListView(children: <Widget>[])
---my code goes here---

Answer 1

you must call setState(() => isLoading = false;) so Flutter can update the state of the view, and in doing so It will hide your CircularProgressIndicator.

Answer 2

Exception('Failed to load internet'); <-
not a good idea since you'r calling the fetchOrganizationData() without a try catch block
It would be better to try something like :
class _DashboardState extends State<Dashboard> {
bool isLoading = false;
bool isFailure = false;
List<OrganizationModel> orgModelList; // this was missing
//since your not using the return value ( it's saved in the state directly ) you could not set the return type
fetchOrganizationData() async {
isLoading = true;
isFailure = false;
var response = await http.get(organizationAPI);
if (response.statusCode == 200) {
final items = json.decode(response.body).cast<Map<String, dynamic>>();
orgModelList = items.map<OrganizationModel>((json) {
return OrganizationModel.fromJson(json);
}).toList();
isFailure = false;
// the return is not required
} else {
isFailure = true;
}
isLoading = false;
setState((){}); // by calling this after the whole state been set, you reduce some code lines
//setState is required to tell flutter to rebuild this widget
}
This way you have a isFailure flag saying if something went wrong while fetching.