title: Flutter - How to display two connected lists in single page?
body: <p>I want to create a two list sections Upper list and lower list on the same page. Clicking on any one of the upper list item, displays a list associated with it on the lower list pane. How can I implement this?</p>
  
  <p>I have tried following methods but with no luck
  1. I tried making lists within a list, but was unable to pass the chosen list details to show it in the lower section.
  2. I also tried creating one upper list, assigned a number to it, and then, passed the number (via onTap) to a variable, which would then choose the second list depending upon this given number. I couldn't complete this either.</p>