title: Add label to UITextField
body: <p>In question <a href="https://stackoverflow.com/questions/663830">663830</a>, Isaac asks about adding a button to a text field. Can someone show code to add a label to the .rightView property?</p>
  
  <p>Or, is there some better way to include 'permanent' text in a text field?</p>
  
  <p>This is for a calculator that would include units in the field (mg, kg, etc.) without having to maintain a label outside of the text field. Sort of like permanent placeholder text?</p>
  
  <p>Thanks,
  Chris</p>