public void addOnPageChangeListener(ViewPagerEx.OnPageChangeListener onPageChangeListener){
        if(onPageChangeListener != null){
            mViewPager.addOnPageChangeListener(onPageChangeListener);
        }
    }
{@link com.daimajia.slider.library.Indicators.PagerIndicator} shape, rect or oval.
library/src/main/java/com/daimajia/slider/library/SliderLayout.java