build method

@override Widget build(BuildContext context, Animation<double> primaryAnimation, Animation<double> secondaryAnimation, Widget child,)

Implementation

@override
Widget build(BuildContext context, Animation<double> primaryAnimation,
    Animation<double> secondaryAnimation, Widget child) {
  var exitAnimation = secondaryAnimation as ProxyAnimation;

  if (!exitAnimation.isDismissed) {
    var animation = CurvedAnimation(parent: secondaryAnimation, curve: curve);

    return Container(
        color: backgroundColor,
        child: Transform(
          alignment: _exitPageAlignment,
          transform: (direction == AxisDirection.left ||
                  direction == AxisDirection.right)
              ? (Matrix4.identity()..scale(1.0 - animation.value, 1.0))
              : (Matrix4.identity()..scale(1.0, 1.0 - animation.value)),
          child: child,
        ));
  } else {
    var animation = CurvedAnimation(parent: primaryAnimation, curve: curve);

    return Transform(
      alignment: _enterPageAlignment,
      transform: (direction == AxisDirection.left ||
              direction == AxisDirection.right)
          ? (Matrix4.identity()..scale(animation.value, 1.0))
          : (Matrix4.identity()..scale(1.0, animation.value)),
      child: child,
    );
  }
}