private boolean collapseBottomSheet() {
        if (mBehavior != null && mBehavior.getState() != BottomSheetBehavior.STATE_COLLAPSED) {
            mBehavior.setState(BottomSheetBehavior.STATE_COLLAPSED);
            return true;
        }
        return false;
    }
Default UI Activity for simplest usage, containing layout achieve {@link BottomSheetBehavior}.
Only support SINGLE_IMG and VIDEO Mode.

@author ChenSL
boxing-impl/src/main/java/com/bilibili/boxing_impl/ui/BoxingBottomSheetActivity.java