我正在尝试实现类别的Ajax导航，为此，我需要代码如下所示：

<ul>
  <li data-level="1">Parent Category</li>
  <li data-level="1">Parent Category
    <ul class="children">
       <li class="sub-category" data-level="2">Subcategory
       <ul class="children">
         <li class="sub-sub-category" data-level="3">Sub Subcategory</li>
       </ul>
       </li>
    </ul>
  </li>
</ul>

我已经定义了一个walker，它创建了一些类似的东西，还在子类ul周围添加了一个div，并在不包含任何子类的类别中添加了一个类。它在第一级子类别中运行良好，但我被困在那里，似乎无法正确创建下一级子类别。这是我的助行器：

class Navigation_Catwalker extends Walker_Category {

// Configure the start of each level
function start_lvl(&$output, $depth = 0, $args = array()) {
    $output .= "";
}

// Configure the end of each level
function end_lvl(&$output, $depth = 0, $args = array()) {
    $output .= "";
}

// Configure the start of each element
function start_el( &$output, $category, $depth = 0, $args = array(), $id = 0) {

    // Set the category name and slug as a variables for later use
    $cat_name = esc_attr( $category->name );
    $cat_name = apply_filters( \'list_cats\', $cat_name, $category );
    $cat_slug = esc_attr( $category->slug );
    $n_depth = $depth + 1;
    $termchildren = get_term_children( $category->term_id, $category->taxonomy );
    if(count($termchildren)===0){
        $class .=  \'i-dont-have-kids\';
    }
    // Configure the output for the top list element and its URL
    if ( $depth === 0 ) {
        $link = \'<a class="parent-category-dropdown" href="#"\' . \'>\' . $cat_name . \'</a>\';
        $indent = str_repeat("\\t", $depth);
        $output .= "\\t<li class=\'parent-category $class " . $cat_slug . "\' data-level=\'$n_depth\'>$link\\n$indent<div class=\'children\'><ul>\\n<li class=\'parent-name\' data-level=\'$n_depth\'>" . $cat_name . "</li>";
    }

    // Configure the output for lower level list elements and their URL\'s
    if ( $depth === 1 ) {
        $link = \'<a href="#"\' . \'>\' . $cat_name . \'</a>\';
        $output .= "\\t<li class=\'sub-category $class\' data-level=\'$n_depth\'>$link\\n";
    } 
    if( $depth > 1) {
      $link = \'<a href="#"\' . \'>\' . $cat_name . \'</a>\';
       $output .= "\\n<li class=\'sub-category $class\' data-level=\'$n_depth\'>$link\\n";
    }


}

// Configure the end of each element
function end_el(&$output, $page, $depth = 0, $args = array() ) {
    if ( $depth === 0 ) {
        $indent = str_repeat("\\t", $depth);
        $output .= "$indent</ul>\\n</div>\\n";
    }
    if ( $depth > 0 ) {
        $output .= "</li>";
    }

}

}

有人有什么想法吗？

class Navigation_Catwalker extends Walker_Category {

// Configure the start of each level
function start_lvl(&$output, $depth = 0, $args = array()) {
    $output .= "";
}

// Configure the end of each level
function end_lvl(&$output, $depth = 0, $args = array()) {
    $output .= "";
}

// Configure the start of each element
function start_el( &$output, $category, $depth = 0, $args = array(), $id = 0) {

    // Set the category name and slug as a variables for later use
    $cat_name = esc_attr( $category->name );
    $cat_name = apply_filters( \'list_cats\', $cat_name, $category );
    $cat_slug = esc_attr( $category->slug );
    $n_depth = $depth + 1;
    $termchildren = get_term_children( $category->term_id, $category->taxonomy );
    $class = \'\';
    if(count($termchildren)===0){
        $class .=  \'i-dont-have-kids\';
    }

    // Configure the output for the top list element and its URL
    if ( count($termchildren)>0) {
        $link = \'<a class="parent-category-dropdown" href="#"\' . \'>\' . $cat_name . \'</a>\';
        $indent = str_repeat("\\t", $depth);
        $output .= "\\t<li class=\'parent-category $class " . $cat_slug . "\' data-level=\'$n_depth\'>$link\\n$indent<div class=\'children\'><ul>\\n<li class=\'parent-name\'>" . $cat_name . "</li>";
    }

    // Configure the output for lower level list elements and their URL\'s
    if ( count($termchildren)===0) {
        $link = \'<a href="#">\' . $cat_name . \'</a>\';
        $output .= "\\t<li class=\'sub-category $class\' data-level=\'$n_depth\'>$link\\n";
    } 
    // if( $depth > 1) {
    //   $link = \'<a href="#">\' . $cat_name . \'</a>\';
    //    $output .= "\\n<li class=\'sub-category $class\' data-level=\'$n_depth\'>$link\\n";
    // }
}

// Configure the end of each element
function end_el(&$output, $category, $depth = 0,$args = array()) {
  $termchildren = get_term_children( $category->term_id, $category->taxonomy );
    if (count($termchildren)>0) {
        $indent = str_repeat("\\t", $depth);
        $output .= "$indent</ul>\\n</div>\\n";
    }
    if (count($termchildren)===0 ) {
        $output .= "</li>";
    }

}

}