bool _handleScrollNotification(ScrollNotification notification)
{
if (!widget.notificationPredicate(notification))
{
return(false);
}
if (notification is OverscrollNotification)
{
_GlowController controller = null;
OverscrollNotification _notification = notification as OverscrollNotification;
if (_notification.overscroll < 0.0f)
{
controller = _leadingController;
}
else if (_notification.overscroll > 0.0f)
{
controller = _trailingController;
}
else
{
D.assert(false, () => "over scroll cannot be 0.0f.");
}
bool isLeading = controller == _leadingController;
if (_lastNotificationType != typeof(OverscrollNotification))
{
OverscrollIndicatorNotification confirmationNotification =
new OverscrollIndicatorNotification(leading: isLeading);
confirmationNotification.dispatch(context);
_accepted[isLeading] = confirmationNotification._accepted;
}
D.assert(controller != null);
D.assert(_notification.metrics.axis() == widget.axis);
if (_accepted[isLeading])
{
if (_notification.velocity != 0.0f)
{
D.assert(_notification.dragDetails == null);
controller.absorbImpact(_notification.velocity.abs());
}
else
{
D.assert(_notification.overscroll != 0.0f);
if (_notification.dragDetails != null)
{
D.assert(_notification.dragDetails.globalPosition != null);
RenderBox renderer = (RenderBox)_notification.context.findRenderObject();
D.assert(renderer != null);
D.assert(renderer.hasSize);
Size size = renderer.size;
Offset position = renderer.globalToLocal(_notification.dragDetails.globalPosition);
switch (_notification.metrics.axis())
{
case Axis.horizontal:
controller.pull(_notification.overscroll.abs(), size.width,
position.dy.clamp(0.0f, size.height), size.height);
break;
case Axis.vertical:
controller.pull(_notification.overscroll.abs(), size.height,
position.dx.clamp(0.0f, size.width), size.width);
break;
}
}
}
}
}
else if (notification is ScrollEndNotification || notification is ScrollUpdateNotification)
{
if ((notification as ScrollEndNotification).dragDetails != null)
{
_leadingController.scrollEnd();
_trailingController.scrollEnd();
}
}
_lastNotificationType = notification.GetType();
return(false);
}
public static bool defaultScrollNotificationPredicate(ScrollNotification notification)
{
return(notification.depth == 0);
}