/**
  * return a random Transformer between [0, the length of enum -1)
  *
  * @return BaseTransformer
  */
 public BaseTransformer getShuffleTransformer() {
   BaseTransformer t = null;
   int transformerNumber = Transformer.values().length;
   int random = new Random().nextInt(transformerNumber - 1);
   Transformer ts = Transformer.values()[random];
   switch (ts) {
     case Default:
       t = new DefaultTransformer();
       break;
     case Accordion:
       t = new AccordionTransformer();
       break;
     case Background2Foreground:
       t = new BackgroundToForegroundTransformer();
       break;
     case CubeIn:
       t = new CubeInTransformer();
       break;
     case DepthPage:
       t = new DepthPageTransformer();
       break;
     case Fade:
       t = new FadeTransformer();
       break;
     case FlipHorizontal:
       t = new FlipHorizontalTransformer();
       break;
     case FlipPage:
       t = new FlipPageViewTransformer();
       break;
     case Foreground2Background:
       t = new ForegroundToBackgroundTransformer();
       break;
     case RotateDown:
       t = new RotateDownTransformer();
       break;
     case RotateUp:
       t = new RotateUpTransformer();
       break;
     case Stack:
       t = new StackTransformer();
       break;
     case Tablet:
       t = new TabletTransformer();
       break;
     case ZoomIn:
       t = new ZoomInTransformer();
       break;
     case ZoomOutSlide:
       t = new ZoomOutSlideTransformer();
       break;
     case ZoomOut:
       t = new ZoomOutTransformer();
       break;
   }
   return t;
 }
 /**
  * set preset PagerTransformer via the name of transforemer.
  *
  * @param transformerName the transformer name in string
  */
 public void setPresetTransformer(String transformerName) {
   for (Transformer t : Transformer.values()) {
     if (t.equals(transformerName)) {
       setPresetTransformer(t);
       return;
     }
   }
 }
 /**
  * set a preset viewpager transformer by id.
  *
  * @param transformerId the recongized transformer ID
  */
 public void setPresetTransformer(int transformerId) {
   for (Transformer t : Transformer.values()) {
     if (t.ordinal() == transformerId) {
       setPresetTransformer(t);
       break;
     }
   }
 }