code: public NavigationDrawerActivity setDrawerLayout(DrawerLayout drawer) {
          mDrawer = drawer;
          if (mDrawer.getFitsSystemWindows()) { // let it draw the status bar
              getWindow().setStatusBarColor(TRANSPARENT);
          }
          return this;
      }
docs: Connect the DrawerLayout to the ActionBar. Should be called in
  {@link #onCreate(Bundle) onCreate}. Must be called before
  {@link Activity#onPostCreate(Bundle) onPostCreate} executes.