code: private void applyFullPagerState(float position, boolean isLeaving) {
          views.fullBackground.setVisibility(position == 0f ? View.INVISIBLE : View.VISIBLE);
          views.fullBackground.setAlpha(position);
  
          views.pagerToolbar.setVisibility(position == 0f ? View.INVISIBLE : View.VISIBLE);
          views.pagerToolbar.setAlpha(isSystemUiShown() ? position : 0f);
  
          views.pagerTitle.setVisibility(position == 1f ? View.VISIBLE : View.INVISIBLE);
  
          if (isLeaving && position == 0f) {
              pagerAdapter.setActivated(false);
              showSystemUi(true);
          }
      }
docs: Applying pager image animation state: fading out toolbar, title and background.