title: how to reload an opened tab bar in swift
body: <p>my application has three tabs. In tab 1 a view controller lets the user add the name of a contact to tab 2 (A button does this task). As soon as the button is pressed the name gets added to tab 2 and the button is disabled for future operations.</p>
  
  <p>But when the user deletes the name from tab 2 the button should be enabled again. I am able to do this if i reload the tab 1 through the navigation controller but if i switch to tab 1 from 2 the button is still disabled even after the user has deleted the name from tab 2.</p>
  
  <p>how to refresh tab 1 when the user has deleted the name in tab 2</p>