updateUserScrollDirection method Null safety

  1. @protected
  2. @visibleForTesting
void updateUserScrollDirection(
  1. ScrollDirection value
)

Set userScrollDirection to the given value.

If this changes the value, then a UserScrollNotification is dispatched.

Implementation

@protected
@visibleForTesting
void updateUserScrollDirection(ScrollDirection value) {
  assert(value != null);
  if (userScrollDirection == value) {
    return;
  }
  _userScrollDirection = value;
  didUpdateScrollDirection(value);
}