code: private void setAnimationProgress(float progress) {
          if (isAlphaUsedForScale()) {
              setColorViewAlpha((int) (progress * MAX_ALPHA));
          } else {
              ViewCompat.setScaleX(mCircleView, progress);
              ViewCompat.setScaleY(mCircleView, progress);
          }
      }
docs: Pre API 11, this does an alpha animation.
  
  @param progress