在 Wordpress menu-walker 中使用中继器字段

Question

>我正在使用walker菜单功能为每个菜单项创建一个子菜单。我正在使用中继器字段来创建 info-div，对于当前页面上的每个the_sub_field('info_block_img_file')，我想在菜单中输出一个新li。但是我现在不知道如何在助行器中正确实现它。这是我尝试过的，显然没有用：

    var $tree_type = array( 'post_type', 'taxonomy', 'custom' );
    var $db_fields = array( 'parent' => 'menu_item_parent', 'id' => 'db_id' );
    function start_lvl( &$output, $depth = 0, $args = array() ) {
        $indent = str_repeat("t", $depth);
        $output .= "n$indent<ul class="sub-menu">n";
    }
    function end_lvl( &$output, $depth = 0, $args = array() ) {
        $indent = str_repeat("t", $depth);
        $output .= "$indent</ul>n";
    }
    function start_el( &$output, $item, $depth = 0, $args = array(), $id = 0 ) {
        $indent = ( $depth ) ? str_repeat( "t", $depth ) : '';
        $class_names = $value = '';
        $classes = empty( $item->classes ) ? array() : (array) $item->classes;
        $classes[] = 'menu-item-' . $item->ID;
        $class_names = join( ' ', apply_filters( 'nav_menu_css_class', array_filter( $classes ), $item, $args ) );
        $class_names = $class_names ? ' class="' . esc_attr( $class_names ) . '"' : '';
        $id = apply_filters( 'nav_menu_item_id', 'menu-item-'. $item->ID, $item, $args );
        $id = $id ? ' id="' . esc_attr( $id ) . '"' : '';
        $output .= $indent . '<li' . $id . $value . $class_names .'>';
        $atts = array();
        $atts['title']  = ! empty( $item->attr_title ) ? $item->attr_title : '';
        $atts['target'] = ! empty( $item->target )     ? $item->target     : '';
        $atts['rel']    = ! empty( $item->xfn )        ? $item->xfn        : '';
        $atts['href']   = ! empty( $item->url )        ? $item->url        : '';

        $atts = apply_filters( 'nav_menu_link_attributes', $atts, $item, $args );
        $attributes = '';
        foreach ( $atts as $attr => $value ) {
            if ( ! empty( $value ) ) {
                $value = ( 'href' === $attr ) ? esc_url( $value ) : esc_attr( $value );
                $attributes .= ' ' . $attr . '="' . $value . '"';
            }
        }
        $item_output = $args->before;
        $item_output .= '<a'. $attributes .'>';
        $item_output .= $args->link_before . apply_filters( 'the_title', $item->title, $item->ID ) . $args->link_after;
        $item_output .= $args->after;
        $item_output .= '</a>';

        $output .= apply_filters( 'walker_nav_menu_start_el', $item_output, $item, $depth, $args );
        //Here’s where I’m trying to put my submenu:
        $output .= '<ul id="about" class="dropDown">'. if(get_field('info_block')):
                while(has_sub_field('info_block')): .'
        <li><a href="#">'. get_sub_field('info_block_header') .'</a></li>'. endwhile; endif; .
        </ul>'; 
    }   function end_el( &$output, $item, $depth = 0, $args = array() ) {
        $output .= "</li>n";
    }
} // Walker_Nav_Menu
?>

Answer 1

class Custom_walker_class extends Walker {
  var $db_fields = array( 'parent' => 'menu_item_parent', 'id' => 'db_id' );
  function start_lvl( &$output, $depth = 0, $args = array() ) {
    $indent = str_repeat("t", $depth);
    $output .= "n$indent<ul>n";
  }
  function end_lvl( &$output, $depth = 0, $args = array() ) {
    $indent = str_repeat("t", $depth);
    $output .= "$indent</ul>n";
  }
  function start_el( &$output, $item, $depth = 0, $args = array(), $id = 0 ) {
    global $wp_query;
    $indent = ( $depth ) ? str_repeat( "t", $depth ) : '';
    $class_names = $value = '';
    $classes = empty( $item->classes ) ? array() : (array) $item->classes;
    /* Add active class */
    if(in_array('current-menu-item', $classes)) {
      $classes[] = 'active';
      unset($classes['current-menu-item']);
    }
    /* Check for children */
    $children = get_posts(array('post_type' => 'nav_menu_item', 'nopaging' => true, 'numberposts' => 1, 'meta_key' => '_menu_item_menu_item_parent', 'meta_value' => $item->ID));
    if (!empty($children)) {
      $classes[] = 'has-sub';
    }
    $class_names = join( ' ', apply_filters( 'nav_menu_css_class', array_filter( $classes ), $item, $args ) );
    $class_names = $class_names ? ' class="' . esc_attr( $class_names ) . '"' : '';
    $id = apply_filters( 'nav_menu_item_id', 'menu-item-'. $item->ID, $item, $args );
    $id = $id ? ' id="' . esc_attr( $id ) . '"' : '';
    $output .= $indent . '<li' . $id . $value . $class_names .'>';
    $attributes  = ! empty( $item->attr_title ) ? ' title="'  . esc_attr( $item->attr_title ) .'"' : '';
    $attributes .= ! empty( $item->target )     ? ' target="' . esc_attr( $item->target     ) .'"' : '';
    $attributes .= ! empty( $item->xfn )        ? ' rel="'    . esc_attr( $item->xfn        ) .'"' : '';
    $attributes .= ! empty( $item->url )        ? ' href="'   . esc_attr( $item->url        ) .'"' : '';
    $item_output = $args->before;
    $item_output .= '<a'. $attributes .'><span>';
    $item_output .= $args->link_before . apply_filters( 'the_title', $item->title, $item->ID ) . $args->link_after;
    $item_output .= '</span></a>';
    $item_output .= $args->after;
    // you need to call your custom out before applying filter
    $output .= '<ul id="about" class="dropDown">';
            if (get_field('info_block')):
                 while (has_sub_field('info_block')): ;
               $output .='<li><a href="#">' . get_sub_field('info_block_header') . '</a></li>';
                endwhile; 
            endif;
      $output .= '</ul>';
    $output .= apply_filters( 'walker_nav_menu_start_el', $item_output, $item, $depth, $args );
  }
  function end_el( &$output, $item, $depth = 0, $args = array() ) {
    $output .= "</li>n";
  }
}

1. 您在忘记使用'. endwhile; endif; .附近遇到语法错误连接变量后的单引号'。

2. 您需要在applying_filter函数之前调用自定义输出，因为这将在调用此函数后立即返回输出功能。