public void setSectionFooterSelected(int sectionIndex, boolean selected) {
        SectionSelectionState state = getSectionSelectionState(sectionIndex);

        if (state.section) {
            return;
        }

        if (state.footer != selected) {
            state.footer = selected;
            notifySectionFooterChanged(sectionIndex);
        }
    }
Select the footer of a section

@param sectionIndex index of section
@param selected     selection state
android/modules/module_common/src/main/java/github/tornaco/android/thanos/widget/section/SectioningAdapter.java