@Override
        public int getViewVerticalDragRange(View child) {
            if (mHideable) {
                return mParentHeight - mMinOffset;
            } else {
                return mMaxOffset - mMinOffset;
            }
        }
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