title: Get navigation/action bar height
body: <p>I have a Xamarin Forms project which uses a custom toolbar for Android.
  The toolbar is defined as Layout in axml and I set the minHeight for the Toolbar to the height of the standard action bar.</p>
  
  <p>For a specific page in my app I have a custom page renderer where I need the height of the top (navigation/action) bar.</p>
  
  <p>I've already tried to get the height with FindViewByID and get the height with TypedValue but that only gave me 0 back.</p>
  
  <p>What else can I try to get the height of the bar in my page renderer?</p>