Unhandled Exception in _PlutoLazyPaginationState.setPage

[s-yanev]

Describe the bug
An unhandled exception occurs when navigating to another page while PlutoLazyPagination widget is still processing an async request :

Unhandled Exception: 'package:flutter/src/widgets/scroll_controller.dart': Failed assertion: line 170 pos 12: '_positions.isNotEmpty': ScrollController not attached to any scroll views.
#0      _AssertionError._doThrowNew (dart:core-patch/errors_patch.dart:51:61)
#1      _AssertionError._throwNew (dart:core-patch/errors_patch.dart:40:5)
#2      ScrollController.jumpTo (package:flutter/src/widgets/scroll_controller.dart:170:12)
#3      _PlutoLazyPaginationState.setPage.<anonymous closure> (package:pluto_grid/src/plugin/pluto_lazy_pagination.dart:183:45)
<asynchronous suspension>

To Reproduce
Steps to reproduce the behavior:

1. Create a PlutoGrid with a PlutoLazyPagination widget in it.
2. Mock the fetch request to some long operation, for example:

await Future.delayed(const Duration(seconds: 5));

3. While the async operation is working try to navigate to some other screen.

Expected behavior
Check if the ScrollController is actually attached to a view before attempting to do the jumpTo() action.

Additional context
The place where the exception happens is in the pluto_lazy_pagination.dart file, at the setPage() function, line 183 :

void setPage(int page) async {
    if (_isFetching) return;

    _isFetching = true;

    stateManager.setShowLoading(true, level: PlutoGridLoadingLevel.rows);

    widget
        .fetch(
      PlutoLazyPaginationRequest(
        page: page,
        sortColumn: stateManager.getSortedColumn,
        filterRows: stateManager.filterRows,
      ),
    )
        .then((data) {
      stateManager.scroll.bodyRowsVertical!.jumpTo(0); // <-- Unhandled Exception here

      stateManager.refRows.clearFromOriginal();
      stateManager.insertRows(0, data.rows);

      setState(() {
        _page = page;

        _totalPage = data.totalPage;

        _isFetching = false;
      });

      stateManager.setShowLoading(false);
    });
  }

It seems that when the async operation is invoked, there is a possibility that when the then() callback is called the PlutoGrid to be already removed from the screen.

One possible solution for resolving the issue can be to just check if the widget is still mounted. Something like this:

if(mounted) {
            stateManager.scroll.bodyRowsVertical!.jumpTo(0);

            stateManager.refRows.clearFromOriginal();
            stateManager.insertRows(0, data.rows);

            setState(() {
              _page = page;

              _totalPage = data.totalPage;

              _isFetching = false;
            });

            stateManager.setShowLoading(false);
          }

[s-yanev]

Issue is fixed with PR - #830

[github-actions]

This issue is stale because it has been open for 30 days with no activity.

[github-actions]

This issue was closed because it has been inactive for 14 days since being marked as stale.