LauncherActivity.kt

rvApps.addOnScrollListener(object : RecyclerView.OnScrollListener() {
            override fun onScrolled(recyclerView: RecyclerView, dx: Int, dy: Int) { 
                recyclerView.forEachVisibleHolder { holder: AppViewHolder ->
                    holder.rotation
                        // Update the velocity.
                        // The velocity is calculated by the vertical scroll offset.
                        .setStartVelocity(holder.currentVelocity - dx * SCROLL_ROTATION_MAGNITUDE)
                        // Start the animation. This does nothing if the animation is already running.
                        .start()
                }
            }
        })