How to Refresh ListView.Builder when data changes in background? - flutter

Question

I have a ListView which gets data from API, the API call is first made from initState() and assigning to List<DataFromApi> dataFromApi = [];. After sometime am doing a background call again to the same API, Am getting the data and assigning to the same list dataFromApi in
setState(() {
dataFromApi = [];
for (DataFromApi td in resData.data) {
dataFromApi.add(td);
}
});
When logging it, the data changes, but UI not changing. How can I update the ListView?
class HomePage extends StatefulWidget {
#override
_HomePageState createState() => _HomePageState();
}
class _HomePageState extends State<HomePage> {
List<DataFromApi> dataFromApi = [];
#override
void initState() {
loadData();
super.initState();
fetchFirstData();
initTimedDataCall();
}
initTimedDataCall() {
Timer.periodic(Duration(minutes: 5), (timer) {
setState(() {
timedCall();
});
});
}
fetchFirstData() async {
final response = await http.get(
Utils.getDataUrl,
);
if (response.statusCode == 200) {
final resData = DataListFromJson(response.body);
if (resData.status == 1) {
print(response.body);
setState(() {
dataFromApi = [];
for (DataFromApi td in resData.data) {
dataFromApi.add(td);
}
});
}
///
///
/// DOING SOME MORE THINGS IN FIRST CALL
///
///
}
}
timedCall() async {
final response = await http.get(
Utils.getDataUrl,
);
if (response.statusCode == 200) {
final resData = DataListFromJson(response.body);
if (resData.status == 1) {
print(response.body);
setState(() {
dataFromApi = [];
for (DataFromApi td in resData.data) {
dataFromApi.add(td);
}
});
}
}
}
#override
Widget build(BuildContext context) {
return Scaffold(
body: ListView.builder(
itemCount: dataFromApi.length,
itemBuilder: (context, index) {
return Text('${dataFromApi[index].title}');
}
),
);
}
}

Answer 1

Try calling setState after computation is done
timedCall() async {
final response = await http.get(
Utils.getDataUrl,
);
if (response.statusCode == 200) {
final resData = DataListFromJson(response.body);
if (resData.status == 1) {
print(response.body);
dataFromApi = [];
for (DataFromApi td in resData.data) {
dataFromApi.add(td);
}
setState(() {
});
}
}
}
use similar for other methods. This is working at my end