How to do yoyo animation in flutter?

You can listen to the status of an animation using addStatusListener. And on animation end reverse it.

final AnimationController c;
...
c.addStatusListener((status) {
  if (status == AnimationStatus.completed) {
    c.reverse();
  }
  else if (status == AnimationStatus.dismissed) {
    c.forward();
  }
});

The repeat method supports the reverse optional named argument, so you can write

animationController.repeat(reverse: true);

This is the modern, simple solution.