默认WordPress仅在首页显示置顶文章，那么要在分类档案页面显示该分类置顶文章，如何实现呢？可以尝试使用下面的代码。
将代码添加到当前主题函数模板 functions.php 中：
class StickyInCategory {
/**
* A reference to an instance of this class.
*/
private static $instance;
/**
* The array of categories that will have sticky posts moved to the top.
*/
protected $categories;
/**
* Returns an instance of this class.
*/
public static function get_instance() {
if ( null == self::$instance ) {
self::$instance = new StickyInCategory();
}
return self::$instance;
}
/**
* Initializes the plugin by setting filters and administration functions.
*/
private function __construct() {
$this->categories = array();
// Filter retrieved posts
add_filter( 'the_posts', array( $this, 'prepend_sticky_posts' ), 10, 2 );
// Set the 'sticky' class
add_filter( 'post_class', array( $this, 'set_sticky_post_class' ), 10, 3 );
}
/**
* Move sticky posts to the top of the archive listing.
*/
public function prepend_sticky_posts( $posts, $query ) {
if ( !is_admin() && is_main_query() ) {
// Hook to initialise the categories if none specified.
if ( empty( $this->categories ) ) {
$this->categories = apply_filters( 'sia_sticky_categories', $this->categories );
}
// Only continue if we are viewing a category archive.
if ( array_key_exists( 'category_name', $query->query_vars ) ) {
$category_matched = false;
if ( empty( $this->categories ) ) {
// If no categories were supplied by the apply_filters() then operate on all categories.
$category_matched = true;
}
else {
// Check whether the current category is in the list.
$category_matched = in_array( $query->query_vars['category_name'], $this->categories );
}
if ( $category_matched ) {
// Copied from the bottom of WP_Query::get_posts() in wp-includes/class-wp-query.php
$sticky_posts = get_option( 'sticky_posts' );
$num_posts = count( $posts );
$sticky_offset = 0;
// Loop over posts and relocate stickies to the front.
for ( $i = 0; $i < $num_posts; $i++ ) {
if ( in_array( $posts[ $i ]->ID, $sticky_posts ) ) {
$sticky_post = $posts[ $i ];
// Remove sticky from current position
array_splice( $posts, $i, 1 );
// Move to front, after other stickies
array_splice( $posts, $sticky_offset, 0, array( $sticky_post ) );
// Increment the sticky offset. The next sticky will be placed at this offset.
$sticky_offset++;
// Remove post from sticky posts array
$offset = array_search( $sticky_post->ID, $sticky_posts );
unset( $sticky_posts[ $offset ] );
}
}
}
}
}
return $posts;
}
/**
* Set the 'sticky' post class. get_post_class() only does it on the home page.
*/
public function set_sticky_post_class( $classes, $class, $post_ID ) {
// TODO: Consider whether to reference $this->categories.
if ( is_archive() && is_sticky( $post_ID ) ) {
$classes[] = 'sticky';
}
return $classes;
}
}
add_action( 'after_setup_theme', array( 'StickyInCategory', 'get_instance' ) );