code: public void setCurrentPosition(int position, boolean smooth) {
          if (getRealAdapter() == null)
              throw new IllegalStateException("You did not set a slider adapter");
          if(position >= getRealAdapter().getCount()){
              throw new IllegalStateException("Item position is not exist");
          }
          int p = mViewPager.getCurrentItem() % getRealAdapter().getCount();
          int n = (position - p) + mViewPager.getCurrentItem();
          mViewPager.setCurrentItem(n, smooth);
      }
docs: set current slider
  @param position