title: cannot resolve R into variable after Android studio update
body: <p>I have just updated my android studio and now all my resources are errors!</p>
  
  <ul>
  <li>I have debugged and debugged but no avail.</li>
  <li>All my xmls files are okay, </li>
  <li>all strings start with lower case.</li>
  <li>I have also restarted the program</li>
  </ul>