When ScrollController added to short ListView IndicatorController doesn't recive ScrollNotification events from gesture detection about flutter-custom-refresh-indicator

[skaletaPL]

After diving deep to flutter gesture detection algorythms i found out that

• the DragGestureDetectionRecognizer (vertical or horizontal) is added to ScrollableState if and if it has canDrag property set to true.

• the ListView default physics is AlwaysScrollableScrollPhysics - obviously its property canDrag is always true.

• when ListView has controller property set to ScrollController, its physics changes to ClampingScrollPhysics

• ClampingScrollPhysics calculates canDrag property based on vieport size and ListView size. When there is not enough lists elements to overflow, canDrag is set to false and no gesture detection recognizer added to our ListView. ListView does not take part in drag gesture recognition and that is why CustomRefreshIndicator will never be notified.

So to work around the situation mentioned above, one can set physics of ListView to physics: AlwaysScrollableScrollPhysics(parent: ClampingScrollPhysics()),.