title: Can't add to an ArrayList on Android Studio?
body: <p><a href="https://i.stack.imgur.com/GrjRM.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/GrjRM.png" alt="enter image description here"></a></p>
  
  <p>I'm not sure what's causing such warning. 
  Am I doing something wrong? </p>