code: public void setPageMargin(int marginPixels) {
          final int oldMargin = mPageMargin;
          mPageMargin = marginPixels;
  
          final int height = getHeight();
          recomputeScrollPosition(height, height, marginPixels, oldMargin);
  
          requestLayout();
      }
docs: Set the margin between pages.
  
  @param marginPixels Distance between adjacent pages in pixels
  @see #getPageMargin()
  @see #setPageMarginDrawable(Drawable)
  @see #setPageMarginDrawable(int)