前言

面包屑导航可以很有效的seo优化及用户体验，让用户在站内不再迷路，面包屑导航一般是：主页 - 分类 - 子分类 - 文章  可以使用模板函数实现，最好很少用插件，减少网站的请求次数及无用功能。

代码示例

function getcategory_with_child($category){
    $cats = array();
    foreach ($category as $cat){
        if ($cat->category_parent!=0){
            array_push($cats, $cat);
        }
    }
    return $cats;
}
    
function get_category_parents_exe( $id, $link = false, $nicename = false, $visited = array() ) {
    $chains = '';
    $term = get_queried_object();
    $parent = get_term( $id, $term->taxonomy );
    if ( is_wp_error( $parent ) ){
        return $parent;
    }
    if ( $nicename ){
        $name = $parent->slug;
    }
    else{
        $name = $parent->name;
    }
    if ( $parent->parent && ( $parent->parent != $parent->term_id ) && !in_array( $parent->parent, $visited ) ) {
        $visited[] = $parent->parent;
        $chains .= get_category_parents_exe( $parent->parent, $link, $nicename, $visited );
    }
    if ( $link ){
        $chains .= $name .'__/__'. get_category_link( $parent->term_id ).',';
    }
    else{
        $chains .= $name .'__/__,';
    }
    return $chains;
}
function wp_breadcrumbs(){
    
    global $post;
    
    $breadcrumbs = array();
    
    if ( !is_front_page() ) {
        $breadcrumbs[] = array(
            'title' => 'Home',
            'link' => home_url()
        );
        
        if ( is_home() ) {
            $breadcrumbs[] = array(
                'title' => __('Blog'),
                'link' => null
            );
        } 
        
        if ( is_archive() ) {
            
            $post_type = get_post_type();
            $post_type_object = get_post_type_object($post_type);
            $post_type_archive = get_post_type_archive_link($post_type);
            $breadcrumbs[] = array(
                'title' => $post_type_object->labels->name,
                'link' => $post_type_archive
            );
            
            if(is_category() || is_tax()){
                $term = get_queried_object();
                
                $get_term_parents = get_category_parents_exe($term->term_id, true);
                $get_term_parents = rtrim($get_term_parents, ',');
                $term_parents = explode(',', $get_term_parents);
                $terms_count = count($term_parents);
                foreach($term_parents as $key => $parents) {
                    $parents = explode('__/__', $parents);
                    if ($key < $terms_count-1){
                        $breadcrumbs[] = array(
                                'title' => $parents[0],
                                'link' =>  $parents[1]
                        );
                    } else {
                        $breadcrumbs[] = array(
                                'title' => $parents[0],
                                'link' => null
                        );
                    }
                }
                
            }
            if ( is_tag() ) {
                $breadcrumbs[] = array(
                    'title' => single_tag_title('', false),
                    'link' => null
                );
            }
            if ( is_author() ) {
                global $author;
                $userdata = get_userdata( $author );
                $breadcrumbs[] = array(
                    'title' => __('Author: ') . $userdata->display_name,
                    'link' => null
                );
            } 
            
            if( is_day() ) {
                $breadcrumbs[] = array(
                    'title' => get_the_time('Y'),
                    'link' => get_year_link( get_the_time('Y') )
                );
                $breadcrumbs[] = array(
                    'title' => get_the_time('M'),
                    'link' => get_month_link( get_the_time('Y'), get_the_time('m') )
                );
                $breadcrumbs[] = array(
                    'title' => get_the_time('jS') . ' ' . get_the_time('M'),
                    'link' => null
                );
            }
            
            if( is_month() ) {
                $breadcrumbs[] = array(
                    'title' => get_the_time('Y'),
                    'link' => get_year_link( get_the_time('Y') )
                );
                $breadcrumbs[] = array(
                    'title' => get_the_time('M'),
                    'link' => null
                );
            }
            
            if( is_year() ) {
                $breadcrumbs[] = array(
                    'title' => get_the_time('Y'),
                    'link' => null
                );
            }
        }
        
        if ( get_query_var('paged') ) {
            
            if ( ! is_archive() ) {
                $breadcrumbs[] = array(
                    'title' => get_post_type_object(get_post_type())->labels->singular_name,
                    'link' => get_post_type_archive_link(get_post_type_object(get_post_type())->query_var)
                );
            }
            
            $breadcrumbs[] = array(
                'title' => __('Page ') . get_query_var('paged'),
                'link' => null
            );
        } 
        
         if ( is_search() ) {
             $breadcrumbs[] = array(
                'title' => __('Search results for ') . get_search_query(),
                'link' => null
            );
        } 
        
        if ( is_404() ) {
            $breadcrumbs[] = array(
                'title' => __('Error 404'),
                'link' => null
            );
        }
        
        if(is_singular()){
            
            if(is_single()){
                
                $post_type = get_post_type();
                $post_type_object = get_post_type_object($post_type);
                $post_type_archive = get_post_type_archive_link($post_type);
                $breadcrumbs[] = array(
                    'title' => $post_type_object->labels->name,
                    'link' => $post_type_archive
                );
                $term = get_the_category();
                if(!empty($term)) {
                    $term_wc = getcategory_with_child($term);
                    if(!empty($term_wc)){
                        $term = $term_wc;
                    } else {
                        $term = $term;
                    }
                    if(!empty($term)){
                        $term = $term[count($term)-1];
                        
                        $get_term_parents = get_category_parents_exe($term->term_id, true);
                        $get_term_parents = rtrim($get_term_parents, ',');
                        $term_parents = explode(',', $get_term_parents);
                        foreach($term_parents as $parents) {
                            $parents = explode('__/__', $parents);
                            $breadcrumbs[] = array(
                                'title' => $parents[0],
                                'link' => $parents[1]
                            );
                        }
                        
                        
                    }
                }
                
                $taxonomy = 'product_cat';
                $taxonomy_exists = taxonomy_exists($taxonomy);
                if(empty($term) && $taxonomy_exists) {
                    
                    $taxonomy_terms = get_the_terms( $post->ID, $taxonomy );
                    $base_tex = $taxonomy_terms[0];
                    if(count($taxonomy_terms) > 1){
                        $term = get_term( $taxonomy_terms[0]->parent, $taxonomy );
                        
                        $get_term_parents = get_category_parents_exe($term->term_id, true);
                        $get_term_parents = rtrim($get_term_parents, ',');
                        $term_parents = explode(',', $get_term_parents);
                        foreach($term_parents as $parents) {
                            $parents = explode('__/__', $parents);
                            $breadcrumbs[] = array(
                                'title' => $parents[0],
                                'link' => $parents[1]
                            );
                        }
                        
                    }
                    
                    $breadcrumbs[] = array(
                        'title' => $base_tex->name,
                        'link' => get_term_link( $base_tex->term_id )
                    );
                }
                $breadcrumbs[] = array(
                    'title' => get_the_title(),
                    'link' => null
                );
            }
            
            if(is_page()){
                
                  if( $post->post_parent ){
                    $anc = get_post_ancestors( $post->ID );
                    $anc = array_reverse($anc);
                    if ( !isset( $parents ) ) $parents = null;
                    foreach ( $anc as $ancestor ) {
                        $breadcrumbs[] = array(
                            'title' => get_the_title($ancestor),
                            'link' => get_permalink($ancestor)
                        );
                    }
                    $breadcrumbs[] = array(
                        'title' => get_the_title(),
                        'link' => null
                    );
                    
                } else {
                    $breadcrumbs[] = array(
                        'title' => get_the_title(),
                        'link' => null
                    );
                }
            }
        }
    }
    
    $output = '';
    $output .= '<ol class="breadcrumb" itemscope itemtype="http://schema.org/BreadcrumbList">';
    $breadcrumbs = array_combine(range(1, count($breadcrumbs)), $breadcrumbs);
    foreach ($breadcrumbs as $key => $breadcrumb) {
        $output .= '<li class="breadcrumb-item" itemprop="itemListElement" itemscope itemtype="http://schema.org/ListItem">'; 
        if(!empty($breadcrumb['link'])){ 
            $output .= '<a itemprop="item" href="'.$breadcrumb['link'].'">';
        }
        $output .= '<span itemprop="name">'.$breadcrumb['title'].'</span>'; 
        if(!empty($breadcrumb['link'])){
            $output .= '</a>';
        }
        $output .= '<meta itemprop="position" content="'.$key.'" />';
        $output .= '</li> ';
    }
    $output .= '</ol>';
    echo  $output;
}

调用示例

<?php if(function_exists('wp_breadcrumbs')){ wp_breadcrumbs(); } ?>

使用方法

代码示例放在主题文件的function.php下，调用示例放在头部文件的显示位置（自行定义）。