code: public T background(int id) {
          if (view != null) {
              if (id != 0) {
                  view.setBackgroundResource(id);
              } else {
                  if (Build.VERSION.SDK_INT<9) {
                      view.setBackgroundDrawable(null);
                  }
                  else
                      view.setBackground(null);
              }
          }
          return self();
      }
docs: Set view background.
  
  @param id the id
  @return self