@Override
        public void onViewDragStateChanged(int state) {
            if (state == ViewDragHelper.STATE_DRAGGING) {
                setStateInternal(STATE_DRAGGING);
            }
        }
Gets the current state of the bottom sheet.

@return One of {@link #STATE_EXPANDED}, {@link #STATE_COLLAPSED}, {@link #STATE_DRAGGING},
{@link #STATE_SETTLING}, and {@link #STATE_HIDDEN}.
vpbs/src/main/java/biz/laenger/android/vpbs/ViewPagerBottomSheetBehavior.java