private void toggleBottomSheet() {
        if (mBehavior == null) {
            return;
        }
        if (mBehavior.getState() == BottomSheetBehavior.STATE_HIDDEN) {
            mBehavior.setState(BottomSheetBehavior.STATE_COLLAPSED);
        } else {
            mBehavior.setState(BottomSheetBehavior.STATE_HIDDEN);
        }
    }
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