title: ListView padding on scrolling
body: <p>I want to add padding at top of ListView and after scrolling ListView i want to set padding to 0.</p>
  
  <p>I've tried adding padding at top of ListView and Layout but both don't work.</p>
  
  <p>Here's what I exactly want:</p>
  
  <p><img src="https://i.stack.imgur.com/swKVd.png" alt="Before scrolling"></p>
  
  <p>(At top of ListView / Before scrolling)</p>
  
  <p><img src="https://i.stack.imgur.com/i9nPX.png" alt="After scrolling"></p>
  
  <p>(Scrolled down ListView / After scrolling)</p>