title: "error: cannot find symbol class IInAppBillingService"
body: <p>I have the same problem as this: 
  <a href="https://stackoverflow.com/questions/17836234/how-can-i-add-the-aidl-file-to-android-studio-from-the-in-app-billing-example">how can I add the aidl file to Android studio (from the in-app billing example)</a></p>
  
  <ol>
  <li>I have tried moving the file into different directories but it still says that it cannot resolve this.</li>
  <li>I also tried syncing with gradle and the error still persists.</li>
  <li>I've tried rebuilding the project as well :(</li>
  </ol>
  
  <p>I am currently using Android Studio.</p>
  
  <p>My current directory looks like this:</p>
  
  <p><a href="https://i.stack.imgur.com/gIVmC.png" rel="nofollow noreferrer">http://i.stack.imgur.com/gIVmC.png</a> </p>
  
  <p>Could anyone see if I did something wrong with the directory?
  Thanks!</p>