title: Android Navigation with nested bottom navigation
body: <p>I'm new to Android Navigation Component and want to understand how can I use it in my relatively simple scenario where I want to have a single activity approach. I obviously want the system to handle the back stack, also for bottom navigation.</p>
  
  <p>What I need is 2 very simple cases:</p>
  
  <h3>1. Mixed destinations</h3>
  
  <p>Some of the destinations in my navigation graph have bottom navigation, and some not. Imagine that I have a login flow without a bottom navigation and then move to the "real app" where I have bottom navigation. Google says put bottom navigation, drawer, action bar outside of navigation graph, which means they are shown for all destinations.</p>
  
  <p>Is this supported by Navigation Component? Without dirty hacks of hiding/showing bottom nav.</p>
  
  <h3>2. Full screen popups</h3>
  
  <p>Another question - is multiple navhosts supported? Imagine I have a UI with bottom navigation and action bar, which are outside of the nav host area. But then I need to show a full screen popup, like a dialog or a resource selection screen, which will also go over the bottom nav and action bar.</p>
  
  <p>Can I do this as a destination in navigation graph?</p>
  
  <hr>
  
  <p>For both questions any conceptually supported solution is good for me, including switching graphs/hosts during navigation.</p>