title: EXCEPTION CAUGHT BY WIDGETS LIBRARY in flutter
body: <p>When I run my code which is totally fine I get an error saying " EXCEPTION CAUGHT BY WIDGETS LIBRARY" and some parts of the app turns red I don't know why</p>
  
  <pre><code>[This is the code screenshot][1]
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/zX5Qn.jpg" rel="nofollow noreferrer">https://i.stack.imgur.com/zX5Qn.jpg</a></p>