code: public final void setDividerColor(@ColorInt final int color) {
          this.seekBarColor = color;
  
          try {
              Field divider = getClass().getSuperclass().getDeclaredField("mSelectionDivider");
              divider.setAccessible(true);
              divider.set(this, new ColorDrawable(color));
          } catch (NoSuchFieldException | IllegalArgumentException | IllegalAccessException e) {
              Log.w(TAG, "Failed to set divider color", e);
          }
      }
docs: Sets the color of the number picker's divider.
  
  @param color
  The color, which should be set, as an {@link Integer} value