title: Android studio 1.0 do not display drawable-hdpi , drawable-xhdpi, drawable-mdpi,drawable-xxhdpi
body: <p>When I create a new project ,my Android studio 1.0 do not display drawable-hdpi , drawable-xhdpi, drawable-mdpi and drawable-xxhdpi .
  I don't konw the reason.
  This is my res directory structure
  |--res
    |--drawable
    |--layout
    |--menu
    |--values
  Someone help？</p>