build method
Override this method to build widgets that depend on the state of the listenable (e.g., the current value of the animation).
Implementation
@override
Widget build(BuildContext context) {
return Positioned(
top: offsetAnimation.value.dy,
left: isLTR ? offsetAnimation.value.dx : null,
right: isLTR ? null : offsetAnimation.value.dx,
width: size.width,
height: size.height,
child: child,
);
}