StretchingOverscrollIndicator constructor Null safety

const StretchingOverscrollIndicator(
  1. {Key? key,
  2. required AxisDirection axisDirection,
  3. ScrollNotificationPredicate notificationPredicate = defaultScrollNotificationPredicate,
  4. Clip clipBehavior = Clip.hardEdge,
  5. Widget? child}

Creates a visual indication that a scroll view has overscrolled by applying a stretch transformation to the content.

In order for this widget to display an overscroll indication, the child widget must contain a widget that generates a ScrollNotification, such as a ListView or a GridView.

The axisDirection and notificationPredicate arguments must not be null.


const StretchingOverscrollIndicator({
  required this.axisDirection,
  this.notificationPredicate = defaultScrollNotificationPredicate,
  this.clipBehavior = Clip.hardEdge,
}) : assert(axisDirection != null),
     assert(notificationPredicate != null),
     assert(clipBehavior != null);