public final void onSaveMedias(Bundle outState, ArrayList<BaseMedia> selected) {
        if (selected != null && !selected.isEmpty()) {
            outState.putParcelableArrayList(Boxing.EXTRA_SELECTED_MEDIA, selected);
        }
    }
in {@link BoxingConfig.Mode#MULTI_IMG}, call this in {@link Fragment#onSaveInstanceState(Bundle)}.

@param outState Bundle in which to place your saved state.
@param selected the selected medias.
boxing/src/main/java/com/bilibili/boxing/AbsBoxingViewFragment.java