code: public void unfold(View coverView, View detailsView) {
          if (this.coverView == coverView && this.detailsView == detailsView) {
              scrollToPosition(1); // Starting unfold animation
              return;
          }
  
          if ((this.coverView != null && this.coverView != coverView)
                  || (this.detailsView != null && this.detailsView != detailsView)) {
              // Cover or details view is differ - closing details and schedule reopening
              scheduledCoverView = coverView;
              scheduledDetailsView = detailsView;
              foldBack();
              return;
          }
  
          // Enabling children clipping, it will be needed if cover view is bigger then half
          // of details view, see CoverHolderLayout#onMeasyre() method.
          ViewGroup parent = (ViewGroup) getParent();
          // In old versions we can't know if children clipping is enabled, we'll assume it's enabled
          origClipChildren = true;
          if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR2) {
              origClipChildren = parent.getClipChildren();
          }
          parent.setClipChildren(false);
  
          // Initializing foldable views
          setCoverViewInternal(coverView);
          setDetailsViewInternal(detailsView);
          setAdapter(adapter);
  
          setState(STATE_UNFOLDING);
          scrollToPosition(1); // starting unfold animation
      }
docs: Starting unfold animation for given views.