bool _shouldUpdatePosition(Scrollable oldWidget)
{
ScrollPhysics newPhysics = widget.physics;
ScrollPhysics oldPhysics = oldWidget.physics;
do
{
Type newPhysicsType = newPhysics != null?newPhysics.GetType() : null;
Type oldPhysicsType = oldPhysics != null?oldPhysics.GetType() : null;
if (newPhysicsType != oldPhysicsType)
{
return(true);
}
if (newPhysics != null)
{
newPhysics = newPhysics.parent;
}
if (oldPhysics != null)
{
oldPhysics = oldPhysics.parent;
}
} while (newPhysics != null || oldPhysics != null);
Type controllerType = widget.controller == null ? null : widget.controller.GetType();
Type oldControllerType = oldWidget.controller == null ? null : oldWidget.controller.GetType();
return(controllerType != oldControllerType);
}
protected float applyBoundaryConditions(float value)
{
float result = physics.applyBoundaryConditions(this, value);
D.assert(() => {
float delta = value - pixels;
if (result.abs() > delta.abs())
{
throw new UIWidgetsError(
$"{physics.GetType()}.applyBoundaryConditions returned invalid overscroll value.\n" +
$"The method was called to consider a change from {pixels} to {value}, which is a " +
$"delta of {delta:F1} units. However, it returned an overscroll of " +
$"${result:F1} units, which has a greater magnitude than the delta. " +
"The applyBoundaryConditions method is only supposed to reduce the possible range " +
"of movement, not increase it.\n" +
$"The scroll extents are {minScrollExtent} .. {maxScrollExtent}, and the " +
$"viewport dimension is {viewportDimension}.");
}
return(true);
});
return(result);
}