title: How to make a custom progress bar in swift, iOS?
body: <p>I want to fill black color to <code>UIView</code>, based on percentage (10%, 30% 50%...)?
  <a href="https://i.stack.imgur.com/ge3We.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/ge3We.png" alt="enter image description here"></a></p>
  
  <p>What is the right way to do this? </p>