RangeError index invalid value only valid value is empty 0 see also in Flutter - flutter

Question

I'm in a Flutter project using Getx. Every time I enter the screen that lists the records I get an error message as you can see below;
I don't know where I'm going wrong, but I'll leave the main parts of the code. I need to find where I'm going wrong.
Class Repository
Future<List<Post>> getAlbum({
bool isFavoritedPage = false,
bool isNewEdition = false,
}) async {
dio.options.headers['Cookie'] = 'ASP.NET_SessionId=${user.sessionID}';
final response = await dio.get(
isFavoritedPage ? AppConstants.apiFavoritedsPost : AppConstants.apiPosts,
queryParameters: {
'sessionId': user.sessionID,
'CodUserProfile': '${user.codUser!}',
'CodUserLogged': '${user.codUser!}',
'Page': '${page}',
'pagesize': '10',
'myPostOnly': isFavoritedPage ? 'true' : 'false',
},
);
final body = response.data['ListPosts'] as List;
return body.map((post) => Post.fromJson(post)).toList();
}
Class Controller
var lstPost = List<Post>.empty(growable: true).obs;
var page = 1;
var isDataProcessing = false.obs;
// For Pagination
ScrollController scrollController = ScrollController();
var isMoreDataAvailable = true.obs;
#override
void onInit() async {
super.onInit();
// Fetch Data
getPost(page);
//For Pagination
paginateTask();
}
void getPost(var page) {
try {
isMoreDataAvailable(false);
isDataProcessing(true);
getAlbum(page).then((resp) {
isDataProcessing(false);
lstPost.addAll(resp);
}, onError: (err) {
isDataProcessing(false);
showSnackBar("Error", err.toString(), Colors.red);
});
} catch (exception) {
isDataProcessing(false);
showSnackBar("Exception", exception.toString(), Colors.red);
}
}
showSnackBar(String title, String message, Color backgroundColor) {
Get.snackbar(title, message,
snackPosition: SnackPosition.BOTTOM,
backgroundColor: backgroundColor,
colorText: Colors.white);
}
void paginateTask() {
scrollController.addListener(() {
if (scrollController.position.pixels ==
scrollController.position.maxScrollExtent) {
print("reached end");
page++;
getMoreTask(page);
}
});
}
void getMoreTask(var page) {
try {
getAlbum(page).then((resp) {
if (resp.length > 0) {
isMoreDataAvailable(true);
} else {
isMoreDataAvailable(false);
showSnackBar("Message", "Não existem registro", Colors.lightBlueAccent);
}
lstPost.addAll(resp);
}, onError: (err) {
isMoreDataAvailable(false);
showSnackBar("Error", err.toString(), Colors.red);
});
} catch (exception) {
isMoreDataAvailable(false);
showSnackBar("Exception", exception.toString(), Colors.red);
}
}
#override
void onClose() {
searchDrawerEC.dispose();
super.onClose();
}
Future<List<Post>> getAlbum(pagina,[bool isFavoritedPage = false]) async {
final response =
await repository.getAlbum(isFavoritedPage: isFavoritedPage);
return response;
}
Class Page
Expanded(
child: ListView.builder(
itemBuilder: (BuildContext context, int index) {
if (index == controller.lstPost.length - 1 &&
controller.isMoreDataAvailable.value == true) {
return Center(child: CircularProgressIndicator());
}
return PostWidget(post: controller.lstPost[index]);
}
),
),
I'm basing myself on this github project.
https://github.com/RipplesCode/FlutterGetXTodoAppWithLaravel/tree/master/lib/app/modules/home

Answer 1

I don't use getx, but I see something odd in your Listview.builder. It feels as if you're abusing it a little, to also show the "no data" case, and there's also no count. I think it should have a count, so something like this:
if (lstPost.isEmpty) {
return Center(child: CircularProgressIndicator());
} else {
return ListView.builder(
itemCount: lstPost.length,
itemBuilder: (BuildContext context, int index) {
return PostWidget(...);
}
);
}