title: React-Native: Find the height of the Header bar
body: <p>Is there a way to programmatically find the height of the Header bar (the one that shows 'Hitchhiking Map' on the following screenshot? I.e. the height from the top of the screen to the bottom of the Header bar.</p>
  
  <p>A cross-platform solution would be ideal.</p>
  
  <p>Edit: I'm using <a href="https://reactnavigation.org/" rel="nofollow noreferrer">React Navigation</a> which renders the header bar.</p>
  
  <p><a href="https://reactnavigation.org/" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/vdd6w.png" alt="enter image description here"></a></p>