SWELL│目次下にウィジェットを追加するカスタマイズ

register_sidebars( 1,
  array(
    'name'=>'目次下',
    'id' => 'widget-below-toc',
    'description' => '目次下に表示されるウイジェット',
    'before_widget' => '<div id="%1$s" class="widget-below-toc %2$s">',
    'after_widget' => '</div>',
    'before_title' => '<div class="widget-below-toc-title">',
    'after_title' => '</div>',
  )
);

function motoki_widget_below_toc($the_content) {
  if ( is_single() || is_category() && is_active_sidebar( 'widget-below-toc' ) ) {
    ob_start();
    dynamic_sidebar( 'widget-below-toc' );
    $widget_content = ob_get_clean();

    $pos_start = mb_strpos( $the_content, '<h2' ); 
    if ($pos_start === false) {     
    } else {
      $html_before = mb_substr( $the_content, 0, $pos_start );
      $html_after = mb_substr( $the_content, $pos_start );
      $the_content = $html_before . $widget_content . $html_after;
    }
  }
  return $the_content;
}
add_filter( 'the_content','motoki_widget_below_toc', 999 );