title: Android Issue: Project r.java disappears when I clean/rebuild
body: <p>Hi I'm having an issue with the r.java file.  It sometimes doesn't reference my xml files such as styles/strings etc  (No errors).  However I heard project clean/rebuild helps, I did it and it has deleted my r.java file. I've tried refreshing but to no avail. Is there a way of getting it back?  I've been working on it all day and I can't get my head around it. I've started new projects and this always happens.</p>
  
  <p>Please help. Thanks. </p>