title: how to detect tab focus change in @react-navigation/bottom-tabs?
body: <p>i am using <strong>@react-navigation/bottom-tabs</strong> in my react-native project..
  there are three tabs</p>
  <pre><code>| Home | Add | List |
  </code></pre>
  <p>all these screens are supposed to fetch data using 3 different APIs and show it when user visit those tabs.. but the problem is how do i detect when a tab got focus?</p>
  <p>i tried to use the <strong>useIsFocused()</strong>, but its not working...
  suppose i have an API call <strong>GetStudentsName()</strong> in <strong>Home-screen</strong> , and i want it to run whenever the user visits the <strong>HomeTab</strong>....but when i click on the <strong>Add tab</strong>, then also this <strong>GetStudentsName()</strong> Api is getting called!...</p>
  <p>how can i limit this api call only when the tab gets focus, <strong>and not when the tab loses focus</strong>?</p>
  <p>please provide a hook-based solution instead of class based</p>