Refresh calls ignored when other refresh in progress

[prokyhb]

Hello,

I need to be able to refresh page (after filtering) quite frequently (using barcode scanner), but once one "refresh" is in progress and I execute another one, the 2nd gets ignored.

I've tried several approaches like using buffer listener (triggering another refresh after complete status, but refresh is not triggered in listener at all) and another techniques, but with no luck.

Is there any option how to cancel current refresh operation and trigger new one?

Thank you.

[Bertus-W]

was looking for this as well. I saw a thing on the paging controller called controller.value.status which is of the type PagingStatus but that status never seems to change either.

[ShankarKakumani]

I also have this issue now. Not sure how to solve it.
had to move away from library because of this issue.

[r-i-c-o]

I have found a pretty minimalistic way to fix this issue. The root of this problem is that PagingController can't tell the difference between subsequent refreshed states, because they are all equal to each other and are filtered out by ValueNotifier superclass. So we can simply assign some tag (int in my case) in PagingState subclass to guarantee distinction between states after refresh(). Now we can use VersionedPagingController everywhere without additional refactor.

///Implementation of [PagingController] that supports distinction between refreshes
class VersionedPagingController<PageKeyType, ItemType> extends PagingController<PageKeyType, ItemType> {
  VersionedPagingController({required PageKeyType firstPageKey})
      : super.fromValue(
          VersionedPagingState<PageKeyType, ItemType>(version: 0, nextPageKey: firstPageKey),
          firstPageKey: firstPageKey,
        );

  int _currentStateVersion = 0;

  int get currentStateVersion => _currentStateVersion;

  @override
  set value(PagingState<PageKeyType, ItemType> newValue) {
    final versionedState = VersionedPagingState(
      version: _currentStateVersion,
      nextPageKey: newValue.nextPageKey,
      itemList: newValue.itemList,
      error: newValue.error,
    );
    super.value = versionedState;
  }


  @override
  void refresh() {
    _currentStateVersion += 1;
    super.refresh();
  }
}

class VersionedPagingState<PageKeyType, ItemType> extends PagingState<PageKeyType, ItemType> {
  const VersionedPagingState({
    super.nextPageKey,
    super.itemList,
    super.error,
    required this.version,
  });

  final int version;

  @override
  String toString() => 'VersionedPagingState (itemList: $itemList, error: $error, nextPageKey: $nextPageKey, version: $version)';

  @override
  bool operator ==(Object other) {
    if (identical(this, other)) {
      return true;
    }
    return other is VersionedPagingState &&
        other.itemList == itemList &&
        other.error == error &&
        other.nextPageKey == nextPageKey &&
        other.version == version;
  }

  @override
  int get hashCode => Object.hash(
        itemList.hashCode,
        error.hashCode,
        nextPageKey.hashCode,
        version.hashCode,
      );
}