Material Design checklist: hiding app bar on scroll?

Question

Per the new Android Material Design checklist:

http://android-developers.blogspot.com/2014/10/material-design-on-android-checklist.html

Where appr

Answer 1

Ref: https://material.io/develop/android/components/app-bars-bottom

hiding app bar on scroll:

Kotlin: programmatically

  bottomAppBar.hideOnScroll = true