为了分配current-cat 我们将扩展当前帖子的所有类别wp_list_categories 通过专用Walker.

假设当前设置如下所示：

$args = array(
    \'hierarchical\' => 0,
    \'title_li\' => \'\',
    \'show_option_none\' => \'\',
);
wp_list_categories($args);

现在我们添加walker（我们将在下一步中设置），以及一个新的参数highlight 这将提供当前帖子的类别ID数组，并由我们的walker处理。当然，我们还必须填充数组本身。

这导致以下情况：

$highlight = array();
$categories = get_the_category();
foreach ($categories as $category)
    $highlight[] = $category->cat_ID;

$args = array(
    \'hierarchical\' => 0,
    \'title_li\' => \'\',
    \'show_option_none\' => \'\',
    \'highlight\' => $highlight,
    \'walker\' => new TFCategoryWalker(),
);
wp_list_categories($args);

最后一步是步行者本身。基本上，我们采用默认值Walker_Category 类并添加缺少的内容。因此，我们只需定制start_el 作用直接在$class 变量已实例化，我们添加了以下内容：

if (! $highlight) $highlight = array();
elseif (! is_array($highlight)) $highlight = array($highlight);
if (in_array($category->term_id, $highlight)) $class .= \' current-cat\';

就这样。

总之，这是新的walker课程，我们把它放在functions.php 文件：

class TFCategoryWalker extends Walker_Category {

    function start_el( &$output, $category, $depth = 0, $args = array(), $id = 0 ) {
            extract($args);
            $cat_name = esc_attr( $category->name );
            $cat_name = apply_filters( \'list_cats\', $cat_name, $category );
            $link = \'<a href="\' . esc_url( get_term_link($category) ) . \'" \';
            if ( $use_desc_for_title == 0 || empty($category->description) )
                    $link .= \'title="\' . esc_attr( sprintf(__( \'View all posts filed under %s\' ), $cat_name) ) . \'"\';
            else
                    $link .= \'title="\' . esc_attr( strip_tags( apply_filters( \'category_description\', $category->description, $category ) ) ) . \'"\';
            $link .= \'>\';
            $link .= $cat_name . \'</a>\';
            if ( !empty($feed_image) || !empty($feed) ) {
                    $link .= \' \';
                    if ( empty($feed_image) )
                            $link .= \'(\';
                    $link .= \'<a href="\' . esc_url( get_term_feed_link( $category->term_id, $category->taxonomy, $feed_type ) ) . \'"\';
                    if ( empty($feed) ) {
                            $alt = \' alt="\' . sprintf(__( \'Feed for all posts filed under %s\' ), $cat_name ) . \'"\';
                    } else {
                            $title = \' title="\' . $feed . \'"\';
                            $alt = \' alt="\' . $feed . \'"\';
                            $name = $feed;
                            $link .= $title;
                    }
                    $link .= \'>\';
                    if ( empty($feed_image) )
                            $link .= $name;
                    else
                            $link .= "<img src=\'$feed_image\'$alt$title" . \' />\';
                    $link .= \'</a>\';
                    if ( empty($feed_image) )
                            $link .= \')\';
            }
            if ( !empty($show_count) )
                    $link .= \' (\' . intval($category->count) . \')\';
            if ( \'list\' == $args[\'style\'] ) {
                    $output .= "\\t<li";
                    $class = \'cat-item cat-item-\' . $category->term_id;

                    // START customization
                    if (! $highlight) $highlight = array();
                    elseif (! is_array($highlight)) $highlight = array($highlight);
                    if (in_array($category->term_id, $highlight)) $class .= \' current-cat\';
                    // END customization

                    if ( !empty($current_category) ) {
                            $_current_category = get_term( $current_category, $category->taxonomy );
                            if ( $category->term_id == $current_category )
                                    $class .=  \' current-cat\';
                            elseif ( $category->term_id == $_current_category->parent )
                                    $class .=  \' current-cat-parent\';
                    }
                    $output .=  \' class="\' . $class . \'"\';
                    $output .= ">$link\\n";
            } else {
                    $output .= "\\t$link<br />\\n";
            }
    } // function start_el

} // class TFCategoryWalker

References:

• get_the_category 功能代码页Walker 分类法典页Walker_Category 课程来源