code: @Nullable
      private boolean[] getCheckedItems() {
          if (listView != null && adapter != null) {
              boolean[] result = new boolean[adapter.getItemCount()];
  
              for (int i = 0; i < result.length; i++) {
                  result[i] = adapter.isItemChecked(i);
              }
  
              return result;
          } else {
              return checkedItems;
          }
      }
docs: Returns an array, which identifies the currently checked list items.
  
  @return An array, which identifies the currently checked list items, as {@link Boolean} array