code: public void showProgress() {
          mLeftAction.setVisibility(View.GONE);
          mSearchProgress.setAlpha(0.0f);
          mSearchProgress.setVisibility(View.VISIBLE);
          ObjectAnimator.ofFloat(mSearchProgress, "alpha", 0.0f, 1.0f).start();
      }
docs: Shows a circular progress on top of the
  menu action button.
  <p/>
  Call hidProgress()
  to change back to normal and make the menu
  action visible.