Collapsible toolbar programatically in android

Sometimes may need the toolbar collapsible in the initial stage or in a certain condition. In that time we implement the functionality programmatically. Here is the following code or function we can call in a particular condition.

fun setCollapsibleToolbar() {
        val params = appBar.layoutParams as CoordinatorLayout.LayoutParams
        val behavior = params.behavior as AppBarLayout.Behavior?
        if (behavior != null) {
            val valueAnimator: ValueAnimator = ValueAnimator.ofInt()
            valueAnimator.interpolator = DecelerateInterpolator()
            valueAnimator.addUpdateListener { animation ->
                behavior.topAndBottomOffset = (animation.animatedValue as Int)!!
                appBar.requestLayout()
            }
            valueAnimator.setIntValues(0, -900)
            valueAnimator.duration = 400
            valueAnimator.start()
        }
    }