title: How can I programmatically add an autolayout constraint to make a button 50 points above bottom of its superview?
body: <p>I'm struggling to figure out how to use VFL to accomplish this. I always want the button to be 50 points above the bottom of its superview. I don't want to specify the distance between the top of the bottom and the top of its superview because that will vary across devices. </p>
  
  <p>I was only able to find other similar questions using interface builder, but my project does not use interface builder or swift, but I would like to do this programmatically, in Objective-C. </p>
  
  <p>Thanks in advance. </p>