It doesn't work when use a center key in CustomScrollView - Used for bidirectional list

[MiniSuperDev]

Hi, I try to create a bidirectional lazy load list like the like flutter docs said
https://github.com/flutter/flutter/blob/5464c5bac742001448fe4fc0597be939379f88ea/packages/flutter/lib/src/widgets/scroll_view.dart#L502-L513

I create a gist where you can enable a disable the center key, and you can see that only highlight work, but the scrollTo not work when the center key is enable.

how can I keep the scroll to index behavior while have the center key? or maybe do you know other way to create a list that append items to the top of the list by preserving the scroll, the solution that I used is from flutter/flutter#21541 (comment)

thank you

[1203556555]

I also encountered this problem. Have you found any solutions? @MiniSuperDev

[yunhe-lin]

AutoScrollControllerMixin:

while (prevOffset != currentOffset &&
!(contains = isIndexStateInLayoutRange(index))) {
prevOffset = currentOffset;
final nearest = _getNearestIndex(index);
final moveTarget =
_forecastMoveUnit(index, nearest, usedSuggestedRowHeightIfAny)!;
if (moveTarget < 0) //can't forecast the move range
return null;
// assume suggestRowHeight will move to correct offset in just one time.
// if the rule doesn't work (in variable row height case), we will use backup solution (non-suggested way)
final suggestedDuration =
usedSuggestedRowHeightIfAny && suggestedRowHeight != null
? duration
: null;

remove
if (moveTarget < 0) //can't forecast the move range
return null;
is useful

[khomin]

AutoScrollControllerMixin:

while (prevOffset != currentOffset && !(contains = isIndexStateInLayoutRange(index))) { prevOffset = currentOffset; final nearest = _getNearestIndex(index); final moveTarget = _forecastMoveUnit(index, nearest, usedSuggestedRowHeightIfAny)!; if (moveTarget < 0) //can't forecast the move range return null; // assume suggestRowHeight will move to correct offset in just one time. // if the rule doesn't work (in variable row height case), we will use backup solution (non-suggested way) final suggestedDuration = usedSuggestedRowHeightIfAny && suggestedRowHeight != null ? duration : null;

remove if (moveTarget < 0) //can't forecast the move range return null; is useful

there is even no such code