title: UIPickerView animated on bottom for both retina 3.5 and 4
body: <p>Have an UIScrollView (mainScrollView) that is 838 pt height, so it's bigger than both retina 3.5 and retina 4 displays height, and the user can so scroll it down to see all content.</p>
  
  <p>Want to display an animated UIPickerView from the bottom, and it should stay always on the bottom of the screen, independent of screen height (retina 3.5 or 4) or mainScrollView (838 pt) height.</p>
  
  <p>Is there a way to get the "window" or "screen" height and add UIPickerView considering the measures for the different screens? What should be the correct approach to accomplish this?</p>
  
  <p><img src="https://i.stack.imgur.com/nkzDw.jpg" alt="enter image description here"></p>