How to animate the nested view on constraint layout?

Remember, ConstraintSet Animation works as any other animation with two stages - Animation Start and Animation End. So, First set the view constraint as Animation start which means hidden under bottom of the layout.

So, Change the initial constraints as:

<!-- Here app:layout_constraintTop_toBottomOf will position the view under the layout/screen -->
<androidx.constraintlayout.widget.ConstraintLayout
    android:id="@+id/error_layout"
    android:layout_width="0dp"
    android:layout_height="wrap_content"
    android:layout_marginStart="12dp"
    android:layout_marginEnd="12dp"
    android:layout_marginBottom="40dp"
    android:background="#fff"
    android:visibility="visible"
    app:layout_constraintTop_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent">

Then, create the constraints as

//rootLayout is the Id of the parent layout
val constraintSet = ConstraintSet()
constraintSet.clone(rootLayout)
constraintSet.clear(error_layout.id, ConstraintSet.TOP)
constraintSet.connect(error_layout.id, ConstraintSet.BOTTOM, ConstraintSet.PARENT_ID, ConstraintSet.BOTTOM)
val transition: Transition = ChangeBounds()
transition.interpolator = AnticipateOvershootInterpolator(1.0f)
transition.duration = 1200
TransitionManager.beginDelayedTransition(rootLayout, transition)
constraintSet.applyTo(rootLayout)

Then, if you want to hide it again. Just replace the TOP and BOTTOM as

constraintSet.clear(error_layout.id, ConstraintSet.BOTTOM)
constraintSet.connect(error_layout.id, ConstraintSet.TOP, ConstraintSet.PARENT_ID, ConstraintSet.BOTTOM)

GIF took more time than coding :p.

EDIT - To listen to animation updates, especially Animation end as requested, what you can do is you can set a listener on transition as

transition.addListener(object : Transition.TransitionListener {
    override fun onTransitionStart(transition: Transition) {
    }
    override fun onTransitionEnd(transition: Transition) {
    }
    override fun onTransitionCancel(transition: Transition) {
    }
    override fun onTransitionPause(transition: Transition) {
    }
    override fun onTransitionResume(transition: Transition) {
    }
})

Put it just before the beginDelayedTransition().