code: public boolean undoPendingDismiss() {
          boolean existPendingDismisses = existPendingDismisses();
          if (existPendingDismisses) {
              mPendingDismiss.rowContainer.undoContainer.setVisibility(View.GONE);
              mPendingDismiss.rowContainer.dataContainer
                      .animate()
                      .translationX(0)
                      .alpha(1)
                      .setDuration(mAnimationTime)
                      .setListener(null);
              mPendingDismiss = null;
          }
          return existPendingDismisses;
      }
docs: If a view was dismissed and the undo container is showing it will undo and make the data
  container reappear.
  @return whether there were any pending rows to be dismissed.