set_screen_options

set_screen_options: 这是一个WordPress的函数，用于设置WordPress管理区中当前屏幕的屏幕选项。它通常用在主题的 functions.php 文件中，用于定制屏幕选项，比如每页显示的项目数量: 这个函数需要一个参数，是一个要设置的屏幕选项的数组。

在列出文章、页面、评论等时，保存行数的选项。

function set_screen_options() {
	if ( ! isset( $_POST['wp_screen_options'] ) || ! is_array( $_POST['wp_screen_options'] ) ) {
		return;
	}

	check_admin_referer( 'screen-options-nonce', 'screenoptionnonce' );

	$user = wp_get_current_user();

	if ( ! $user ) {
		return;
	}

	$option = $_POST['wp_screen_options']['option'];
	$value  = $_POST['wp_screen_options']['value'];

	if ( sanitize_key( $option ) !== $option ) {
		return;
	}

	$map_option = $option;
	$type       = str_replace( 'edit_', '', $map_option );
	$type       = str_replace( '_per_page', '', $type );

	if ( in_array( $type, get_taxonomies(), true ) ) {
		$map_option = 'edit_tags_per_page';
	} elseif ( in_array( $type, get_post_types(), true ) ) {
		$map_option = 'edit_per_page';
	} else {
		$option = str_replace( '-', '_', $option );
	}

	switch ( $map_option ) {
		case 'edit_per_page':
		case 'users_per_page':
		case 'edit_comments_per_page':
		case 'upload_per_page':
		case 'edit_tags_per_page':
		case 'plugins_per_page':
		case 'export_personal_data_requests_per_page':
		case 'remove_personal_data_requests_per_page':
			// Network admin.
		case 'sites_network_per_page':
		case 'users_network_per_page':
		case 'site_users_network_per_page':
		case 'plugins_network_per_page':
		case 'themes_network_per_page':
		case 'site_themes_network_per_page':
			$value = (int) $value;

			if ( $value < 1 || $value > 999 ) {
				return;
			}

			break;

		default:
			$screen_option = false;

			if ( '_page' === substr( $option, -5 ) || 'layout_columns' === $option ) {
				/**
				 * Filters a screen option value before it is set.
				 *
				 * The filter can also be used to modify non-standard [items]_per_page
				 * settings. See the parent function for a full list of standard options.
				 *
				 * Returning false from the filter will skip saving the current option.
				 *
				 * @since 2.8.0
				 * @since 5.4.2 Only applied to options ending with '_page',
				 *              or the 'layout_columns' option.
				 *
				 * @see set_screen_options()
				 *
				 * @param mixed  $screen_option The value to save instead of the option value.
				 *                              Default false (to skip saving the current option).
				 * @param string $option        The option name.
				 * @param int    $value         The option value.
				 */
				$screen_option = apply_filters( 'set-screen-option', $screen_option, $option, $value ); // phpcs:ignore WordPress.NamingConventions.ValidHookName.UseUnderscores
			}

			/**
			 * Filters a screen option value before it is set.
			 *
			 * The dynamic portion of the hook name, `$option`, refers to the option name.
			 *
			 * Returning false from the filter will skip saving the current option.
			 *
			 * @since 5.4.2
			 *
			 * @see set_screen_options()
			 *
			 * @param mixed   $screen_option The value to save instead of the option value.
			 *                               Default false (to skip saving the current option).
			 * @param string  $option        The option name.
			 * @param int     $value         The option value.
			 */
			$value = apply_filters( "set_screen_option_{$option}", $screen_option, $option, $value );

			if ( false === $value ) {
				return;
			}

			break;
	}

	update_user_meta( $user->ID, $option, $value );

	$url = remove_query_arg( array( 'pagenum', 'apage', 'paged' ), wp_get_referer() );

	if ( isset( $_POST['mode'] ) ) {
		$url = add_query_arg( array( 'mode' => $_POST['mode'] ), $url );
	}

	wp_safe_redirect( $url );
	exit;
}