setPixels method

  1. @override
double setPixels (double newPixels)
override

Update the scroll position (pixels) to a given pixel value.

This should only be called by the current ScrollActivity, either during the transient callback phase or in response to user input.

Returns the overscroll, if any. If the return value is 0.0, that means that pixels now returns the given value. If the return value is positive, then pixels is less than the requested value by the given amount (overscroll past the max extent), and if it is negative, it is greater than the requested value by the given amount (underscroll past the min extent).

The amount of overscroll is computed by applyBoundaryConditions.

The amount of the change that is applied is reported using didUpdateScrollPositionBy. If there is any overscroll, it is reported using didOverscrollBy.

Implementation 

@override
double setPixels(double newPixels) {
  assert(activity.isScrolling);
  return super.setPixels(newPixels);
}