CODEWITHSUNDEEP
flutterdartflutter-cubit
Firdous nath
Firdous nath

Reputation: 1587

Fatal Exception: Bad state: Too many elements

I am getting above error while using addListener on Scroll Controller. Class is initialised once but the method is called multiple times and where the error is occurred.

I have declared controller globally like

ScrollController rwScrollController = ScrollController();

using inside the method like

fetchRewardLadder(
        String code, {
        bool fromFab = false,
      }) async {
        rwScrollController = ScrollController(); //----> initialised
        
    
        GccApiResponse response = await _repository.fetchRewardLadder(
          Variables$Query$fetchRewardLadder(
            code: code,
          ),
        );
        switch (response.status) {
          case Status.ERROR:
            showExceptionSnackbar(message: response.message);
            break;
          default:
            try {
              Query$fetchRewardLadder$fetchRewardLadder reward =
                  Query$fetchRewardLadder$fetchRewardLadder.fromJson(
                response.data["fetchRewardLadder"],
              );
              safeEmit(
                state.copyWith(
                  rewardLadder: reward,
                  isLoading: false,
                ),
              );
              

              rwScrollController.addListener(
                () {
                  //--------- getting error here ----------------
                  if (rwScrollController.position.pixels >
                          (0.95 * rwScrollController.position.maxScrollExtent) &&
                      !state.isLoading &&
                      state.leaderboard == null) {
                    fetchLeaderBoard(code);
                  }
                },
              );
            } catch (e) {
              showExceptionSnackbar(
                message: "Formatting failed" + e.toString(),
              );
            }
        }
      }

full crash logs :

Fatal Exception: io.flutter.plugins.firebase.crashlytics.FlutterError: Bad state: Too many elements. Error thrown Instance of 'ErrorDescription'. at _GrowableList.single(dart:core) at ScrollController.position(scroll_controller.dart:109) at RewardLadderCubit.fetchRewardLadder.(reward_ladder_cubit.dart:136) at ChangeNotifier.notifyListeners(change_notifier.dart:381) at ChangeNotifier.notifyListeners(change_notifier.dart:381) at ScrollPosition.notifyListeners(scroll_position.dart:984) at ScrollPosition.setPixels(scroll_position.dart:281) at ScrollPositionWithSingleContext.setPixels(scroll_position_with_single_context.dart:78) at ScrollPositionWithSingleContext.applyUserOffset(scroll_position_with_single_context.dart:122) at ScrollDragController.update(scroll_activity.dart:387) at ScrollableState._handleDragUpdate(scrollable.dart:719) at DragGestureRecognizer._checkUpdate.(monodrag.dart:483) at GestureRecognizer.invokeCallback(recognizer.dart:253) at DragGestureRecognizer._checkUpdate(monodrag.dart:483) at DragGestureRecognizer.handleEvent(monodrag.dart:330) at PointerRouter._dispatch(pointer_router.dart:98) at PointerRouter._dispatchEventToRoutes.(pointer_router.dart:143) at _LinkedHashMapMixin.forEach(dart:collection) at PointerRouter._dispatchEventToRoutes(pointer_router.dart:141) at PointerRouter.route(pointer_router.dart:127) at GestureBinding.handleEvent(binding.dart:460) at GestureBinding.dispatchEvent(binding.dart:440) at RendererBinding.dispatchEvent(binding.dart:336) at GestureBinding._handlePointerEventImmediately(binding.dart:395) at GestureBinding.handlePointerEvent(binding.dart:357) at GestureBinding._flushPointerEventQueue(binding.dart:314) at GestureBinding._handlePointerDataPacket(binding.dart:295)

Upvotes: -1

Views: 1178

Answers (1)

Firdous nath
Firdous nath

Reputation: 1587

Problem was that whenever I was declaring it globally flutter engine was not disposing the widget as cubit was in use so whenever it re-renders it reassign new scrollController to same listview thus causing error. So I created a new method and used it each time widget re-renders.

  ScrollController getRWController() {
    ScrollController rwScrollController = ScrollController();
    rwScrollController.addListener(
      () {
        if (rwScrollController.position.pixels >
                (0.95 * rwScrollController.position.maxScrollExtent) &&
            !state.isLoading &&
            state.leaderboard == null) {
          fetchLeaderBoard(this.code);
        }
      },
    );
    return rwScrollController;
  }

and used it in listview as

        ListView(
         controller: context.read<RewardLadderCubit>().getRWController(),
         children: [],
        ),

Upvotes: 0

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