code: private void obtainShowHeader(@StyleRes final int themeResourceId) {
          TypedArray typedArray = getContext().getTheme().obtainStyledAttributes(themeResourceId,
                  new int[]{R.attr.materialDialogShowHeader});
          showHeader(typedArray.getBoolean(0, false));
      }
docs: Obtains, whether the dialog's header should be shown, or not, from a specific theme.
  
  @param themeResourceId
  The resource id of the theme, the visibility should be obtained from, as an {@link
  Integer} value