ViewHideAndShow.kt

@RequiresApi(Build.VERSION_CODES.LOLLIPOP)
fun View.hide() {
    // get the center for the clipping circle
    val cx = this.width / 2
    val cy = this.height / 2

    // get the initial radius for the clipping circle
    val initialRadius = hypot(cx.toDouble(), cy.toDouble()).toFloat()
    // create the animation (the final radius is zero)
    val anim = ViewAnimationUtils.createCircularReveal(this, cx, cy, initialRadius, 0f)
    // make the view invisible when the animation is done
    anim.addListener(object : AnimatorListenerAdapter() {
        override fun onAnimationEnd(animation: Animator) {
            super.onAnimationEnd(animation)
            this@hide.visibility = View.INVISIBLE
        }
    })
    // start the animation
    anim.start()
}

@RequiresApi(Build.VERSION_CODES.LOLLIPOP)
fun View.show() {
    // get the center for the clipping circle
    val cx = this.width / 2
    val cy = this.height / 2
    // get the final radius for the clipping circle
    val finalRadius = hypot(cx.toDouble(), cy.toDouble()).toFloat()
    // create the animator for this view (the start radius is zero)
    val anim = ViewAnimationUtils.createCircularReveal(this, cx, cy, 0f, finalRadius)
    // make the view visible and start the animation
    this.visibility = View.VISIBLE
    anim.start()
}