createBallisticSimulation method Null safety

Simulation? createBallisticSimulation(
  1. ScrollMetrics position,
  2. double velocity

Returns a simulation for ballistic scrolling starting from the given position with the given velocity.

This is used by ScrollPositionWithSingleContext in the ScrollPositionWithSingleContext.goBallistic method. If the result is non-null, ScrollPositionWithSingleContext will begin a BallisticScrollActivity with the returned value. Otherwise, it will begin an idle activity instead.

The given position is only valid during this method call. Do not keep a reference to it to use later, as the values may update, may not update, or may update to reflect an entirely unrelated scrollable.


Simulation? createBallisticSimulation(ScrollMetrics position, double velocity) {
  if (parent == null)
    return null;
  return parent!.createBallisticSimulation(position, velocity);