private int getShouldDrawCount(){
        if(mPager.getAdapter() instanceof InfinitePagerAdapter){
            return ((InfinitePagerAdapter)mPager.getAdapter()).getRealCount();
        }else{
            return mPager.getAdapter().getCount();
        }
    }
since we used a adapter wrapper, so we can't getCount directly from wrapper.
@return
library/src/main/java/com/daimajia/slider/library/Indicators/PagerIndicator.java