code: private void showUndoView(@NonNull final View view) {
          mCallback.getPrimaryView(view).setVisibility(View.GONE);
  
          View undoView = mCallback.getUndoView(view);
          undoView.setVisibility(View.VISIBLE);
          ObjectAnimator.ofFloat(undoView, ALPHA, 0f, 1f).start();
      }
docs: Sets the visibility of the primary {@link android.view.View} to {@link android.view.View#GONE}, and animates the undo {@code View} in to view.
  
  @param view the parent {@code View} which contains both primary and undo {@code View}s.