title: How to change 2nd pickerview component based on 1st component selection in a pickerview?
body: <p>I am working on an unit converter app. Once I input numbers to UITextLabel, pickerview will open automatically and upon choosing an option such as Feet, Yards, etc, the result will be displayed. 
  Now, I am looking to extend this functionality for different metrics such as weight, temperature,distance,etc. So this time, I need to </p>
  
  <ul>
  <li>Enter number (Working)</li>
  <li>Open metrics component - Ex: Distance (working)</li>
  <li>Open unit component - Ex: Feet (Stuck)</li>
  <li>Display Result</li>
  </ul>
  
  <p>Please assist how to open a unit pickerview upon choosing an option from metrics pickerview. I found a solution using UITableView <a href="https://stackoverflow.com/questions/16648459/uipickerview-depending-on-uitableview/25312581#25312581">UIPickerView depending on UITableView</a> but I am trying to implement pickerview instead of UITableView. </p>
  
  <p>Any help is much appreciated!</p>