How do I do something when an animation finishes?

To your original question about the ObjectAnimator object you can set up an Animator.AnimatorListener object which defines several animation state callbacks. You want to override public void onAnimationEnd(Animator animation)

animation.addListener(new Animator.AnimatorListener() {
                @Override
                public void onAnimationStart(Animator animation) {

                }

                @Override
                public void onAnimationEnd(Animator animation) {
                    Toast.makeText(VideoEditorActivity.this, "animation ended", Toast.LENGTH_LONG).show();
                }

                @Override
                public void onAnimationCancel(Animator animation) {

                }

                @Override
                public void onAnimationRepeat(Animator animation) {

                }
            });

With androidx you can use doOnEnd method which invoked when the animation has ended

val anim = ObjectAnimator.ofFloat(eva_image, View.TRANSLATION_Y, 0f, 500f)
anim.setDuration(500)
anim.doOnEnd { Toast.makeText(this, "Anim End", Toast.LENGTH_SHORT).show() }
anim.start()

The more modern way of doing this is to use the ViewPropertyAnimator:

view.animate()
    .alpha(0f)
    .withEndAction(new Runnable() {
      @Override
      public void run() {
        // Do something.
      }
    })
    .start();

Or, if you're using RetroLambda:

view.animate()
    .alpha(0f)
    .withEndAction(() -> {
      // Do something.
    })
    .start();