@Override
    protected boolean verifyDrawable(Drawable who) {
        return super.verifyDrawable(who) || who == mMarginDrawable;
    }
Set a drawable that will be used to fill the margin between pages.

@param resId Resource ID of a drawable to display between pages
dkplayer-sample/src/main/java/xyz/doikki/dkplayer/widget/VerticalViewPager.java