Range Error (Index) Flutter GETX : invalid value - flutter

Question

Here I have an error when I fetch data, I take a reference from youtube then I apply and use data from local but when I run it I get an error as I described. here is my source code
Controller.dart
class ProdukKonvensionalController extends GetxController {
var konvenList = <ProdukKonvenModel>[].obs;
var isLoading = true.obs;
#override
void onInit() {
super.onInit();
fetchKonven();
}
Future<void> fetchKonven() async {
final response =
await http.get(Uri.parse('http://192.168.100.207:8080/konven'));
if (response.statusCode == 200) {
ProdukKonvenModel _produkkonvenModel =
ProdukKonvenModel.fromJson(jsonDecode(response.body));
konvenList.add(ProdukKonvenModel(
kategoriNama: _produkkonvenModel.kategoriNama,
kategoriId: _produkkonvenModel.kategoriId,
kontenId: _produkkonvenModel.kontenId,
kontenMenu: _produkkonvenModel.kontenMenu,
kontenParent: _produkkonvenModel.kontenParent,
kontenUrl: _produkkonvenModel.kontenUrl,
));
isLoading.value = true;
} else {
Get.snackbar("Error Loading Data",
'Server Responded: ${response.statusCode}:${response.reasonPhrase.toString()}');
}
}
}
PageView.dart
class ProdukKonvensionalPage extends StatelessWidget {
const ProdukKonvensionalPage({Key? key}) : super(key: key);
#override
Widget build(BuildContext context) {
final _controller = Get.find<ProdukKonvensionalController>();
return Scaffold(
body: SingleChildScrollView(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: [
Text('${_controller.konvenList[0].kategoriNama}'),
],
)),
);
}
}
and the following shows an error

Answer 1

try this
var konvenList = <ProdukKonvenModel>[].obs;
var isLoading = true.obs;
#override
void onInit() {
super.onInit();
fetchKonven();
}
Future<void> fetchKonven() async {
final response = await http.get(Uri.parse('http://192.168.100.207:8080/konven'));
if (response.statusCode == 200) {
ProdukKonvenModel _produkkonvenModel =
ProdukKonvenModel.fromJson(jsonDecode(response.body));
_produkkonvenModel.forEach((element) => konvenList.add(element));
isLoading.value = true;
} else {
Get.snackbar("Error Loading Data",
'Server Responded:
${response.statusCode}:${response.reasonPhrase.toString()}');
}
}
}