initAnimation method

Implementation

@protected
initAnimation() {
  if (controller != null) {
    return;
  }
  animation = buildAnimation();

  controller = createAnimationController(animation);
  controller?.addStatusListener((status) {
    if (status == AnimationStatus.completed) {
      onOpened();
      hole = targetHole ?? AntdMaskHole.zero;
    }
  });
  if (buildAutoAnimation()) {
    openAnimation();
  }
}