Walker_Nav_Menu_Checklist
云策文档标注
概述
Walker_Nav_Menu_Checklist 是 WordPress 中用于生成导航菜单输入项 HTML 列表的 Walker 类,继承自 Walker_Nav_Menu。它主要用于在后台菜单编辑界面创建复选框列表,方便用户选择菜单项。
关键要点
- 继承自 Walker_Nav_Menu,专门处理导航菜单的输入项列表生成。
- 包含核心方法:__construct 用于设置数据库字段,start_lvl 和 end_lvl 控制列表层级结构,start_el 生成每个菜单项的 HTML 输出。
- 在 start_el 方法中处理菜单项数据,包括对象 ID、标题、隐藏字段等,并支持动态占位符和状态添加。
- 自 WordPress 3.0.0 引入,5.9.0 更新参数命名以支持 PHP 8 命名参数。
代码示例
public function start_el( &$output, $data_object, $depth = 0, $args = null, $current_object_id = 0 ) {
global $_nav_menu_placeholder, $nav_menu_selected_id;
$menu_item = $data_object;
$_nav_menu_placeholder = ( 0 > $_nav_menu_placeholder ) ? (int) $_nav_menu_placeholder - 1 : -1;
$possible_object_id = isset( $menu_item->post_type ) && 'nav_menu_item' === $menu_item->post_type ? $menu_item->object_id : $_nav_menu_placeholder;
$possible_db_id = ( ! empty( $menu_item->ID ) ) && ( 0 < $menu_item->ID ) ? (int) $menu_item->ID : 0;
$indent = ( $depth ) ? str_repeat( "t", $depth ) : '';
$output .= $indent . '<li>';
$output .= '<label class="menu-item-title">';
$output .= '<input type="checkbox" class="menu-item-checkbox"';
if ( property_exists( $menu_item, 'front_or_home' ) && $menu_item->front_or_home ) {
$output .= ' add-to-top';
}
$output .= '" name="menu-item[' . $possible_object_id . '][menu-item-object-id]" value="' . esc_attr( $menu_item->object_id ) . '" /> ';
if ( ! empty( $menu_item->label ) ) {
$title = $menu_item->label;
} elseif ( isset( $menu_item->post_type ) ) {
$title = apply_filters( 'the_title', $menu_item->post_title, $menu_item->ID );
}
$output .= isset( $title ) ? esc_html( $title ) : esc_html( $menu_item->title );
if ( empty( $menu_item->label ) && isset( $menu_item->post_type ) && 'page' === $menu_item->post_type ) {
$output .= _post_states( $menu_item, false );
}
$output .= '</label>';
$output .= '<input type="hidden" class="menu-item-db-id" name="menu-item[' . $possible_object_id . '][menu-item-db-id]" value="' . $possible_db_id . '" />';
$output .= '<input type="hidden" class="menu-item-object" name="menu-item[' . $possible_object_id . '][menu-item-object]" value="' . esc_attr( $menu_item->object ) . '" />';
$output .= '<input type="hidden" class="menu-item-parent-id" name="menu-item[' . $possible_object_id . '][menu-item-parent-id]" value="' . esc_attr( $menu_item->menu_item_parent ) . '" />';
$output .= '<input type="hidden" class="menu-item-type" name="menu-item[' . $possible_object_id . '][menu-item-type]" value="' . esc_attr( $menu_item->type ) . '" />';
$output .= '<input type="hidden" class="menu-item-title" name="menu-item[' . $possible_object_id . '][menu-item-title]" value="' . esc_attr( $menu_item->title ) . '" />';
$output .= '<input type="hidden" class="menu-item-url" name="menu-item[' . $possible_object_id . '][menu-item-url]" value="' . esc_attr( $menu_item->url ) . '" />';
$output .= '<input type="hidden" class="menu-item-target" name="menu-item[' . $possible_object_id . '][menu-item-target]" value="' . esc_attr( $menu_item->target ) . '" />';
$output .= '<input type="hidden" class="menu-item-attr-title" name="menu-item[' . $possible_object_id . '][menu-item-attr-title]" value="' . esc_attr( $menu_item->attr_title ) . '" />';
$output .= '<input type="hidden" class="menu-item-classes" name="menu-item[' . $possible_object_id . '][menu-item-classes]" value="' . esc_attr( implode( ' ', $menu_item->classes ) ) . '" />';
$output .= '<input type="hidden" class="menu-item-xfn" name="menu-item[' . $possible_object_id . '][menu-item-xfn]" value="' . esc_attr( $menu_item->xfn ) . '" />';
}注意事项
- 该类主要用于 WordPress 后台的菜单管理界面,开发者可扩展或自定义以适配特定需求。
- 在 start_el 方法中,参数命名在 5.9.0 版本更新为 $data_object 和 $current_object_id,以兼容 PHP 8 命名参数,但内部仍使用 $menu_item 变量保持可读性。
- 使用全局变量 $_nav_menu_placeholder 和 $nav_menu_selected_id 处理动态菜单项和选中状态。
原文内容
Create HTML list of nav menu input items.
Methods
| Name | Description |
|---|---|
| Walker_Nav_Menu_Checklist::__construct | – |
| Walker_Nav_Menu_Checklist::end_lvl | Ends the list of after the elements are added. |
| Walker_Nav_Menu_Checklist::start_el | Start the element output. |
| Walker_Nav_Menu_Checklist::start_lvl | Starts the list before the elements are added. |
Source
class Walker_Nav_Menu_Checklist extends Walker_Nav_Menu {
/**
* @param array|false $fields Database fields to use.
*/
public function __construct( $fields = false ) {
if ( $fields ) {
$this->db_fields = $fields;
}
}
/**
* Starts the list before the elements are added.
*
* @see Walker_Nav_Menu::start_lvl()
*
* @since 3.0.0
*
* @param string $output Used to append additional content (passed by reference).
* @param int $depth Depth of page. Used for padding.
* @param stdClass $args Not used.
*/
public function start_lvl( &$output, $depth = 0, $args = null ) {
$indent = str_repeat( "t", $depth );
$output .= "n$indent<ul class='children'>n";
}
/**
* Ends the list of after the elements are added.
*
* @see Walker_Nav_Menu::end_lvl()
*
* @since 3.0.0
*
* @param string $output Used to append additional content (passed by reference).
* @param int $depth Depth of page. Used for padding.
* @param stdClass $args Not used.
*/
public function end_lvl( &$output, $depth = 0, $args = null ) {
$indent = str_repeat( "t", $depth );
$output .= "n$indent</ul>";
}
/**
* Start the element output.
*
* @see Walker_Nav_Menu::start_el()
*
* @since 3.0.0
* @since 5.9.0 Renamed `$item` to `$data_object` and `$id` to `$current_object_id`
* to match parent class for PHP 8 named parameter support.
*
* @global int $_nav_menu_placeholder
* @global int|string $nav_menu_selected_id
*
* @param string $output Used to append additional content (passed by reference).
* @param WP_Post $data_object Menu item data object.
* @param int $depth Depth of menu item. Used for padding.
* @param stdClass $args Not used.
* @param int $current_object_id Optional. ID of the current menu item. Default 0.
*/
public function start_el( &$output, $data_object, $depth = 0, $args = null, $current_object_id = 0 ) {
global $_nav_menu_placeholder, $nav_menu_selected_id;
// Restores the more descriptive, specific name for use within this method.
$menu_item = $data_object;
$_nav_menu_placeholder = ( 0 > $_nav_menu_placeholder ) ? (int) $_nav_menu_placeholder - 1 : -1;
$possible_object_id = isset( $menu_item->post_type ) && 'nav_menu_item' === $menu_item->post_type ? $menu_item->object_id : $_nav_menu_placeholder;
$possible_db_id = ( ! empty( $menu_item->ID ) ) && ( 0 < $possible_object_id ) ? (int) $menu_item->ID : 0;
$indent = ( $depth ) ? str_repeat( "t", $depth ) : '';
$output .= $indent . '<li>';
$output .= '<label class="menu-item-title">';
$output .= '<input type="checkbox"' . wp_nav_menu_disabled_check( $nav_menu_selected_id, false ) . ' class="menu-item-checkbox';
if ( ! empty( $menu_item->front_or_home ) ) {
$output .= ' add-to-top';
}
$output .= '" name="menu-item[' . $possible_object_id . '][menu-item-object-id]" value="' . esc_attr( $menu_item->object_id ) . '" /> ';
if ( ! empty( $menu_item->label ) ) {
$title = $menu_item->label;
} elseif ( isset( $menu_item->post_type ) ) {
/** This filter is documented in wp-includes/post-template.php */
$title = apply_filters( 'the_title', $menu_item->post_title, $menu_item->ID );
}
$output .= isset( $title ) ? esc_html( $title ) : esc_html( $menu_item->title );
if ( empty( $menu_item->label ) && isset( $menu_item->post_type ) && 'page' === $menu_item->post_type ) {
// Append post states.
$output .= _post_states( $menu_item, false );
}
$output .= '</label>';
// Menu item hidden fields.
$output .= '<input type="hidden" class="menu-item-db-id" name="menu-item[' . $possible_object_id . '][menu-item-db-id]" value="' . $possible_db_id . '" />';
$output .= '<input type="hidden" class="menu-item-object" name="menu-item[' . $possible_object_id . '][menu-item-object]" value="' . esc_attr( $menu_item->object ) . '" />';
$output .= '<input type="hidden" class="menu-item-parent-id" name="menu-item[' . $possible_object_id . '][menu-item-parent-id]" value="' . esc_attr( $menu_item->menu_item_parent ) . '" />';
$output .= '<input type="hidden" class="menu-item-type" name="menu-item[' . $possible_object_id . '][menu-item-type]" value="' . esc_attr( $menu_item->type ) . '" />';
$output .= '<input type="hidden" class="menu-item-title" name="menu-item[' . $possible_object_id . '][menu-item-title]" value="' . esc_attr( $menu_item->title ) . '" />';
$output .= '<input type="hidden" class="menu-item-url" name="menu-item[' . $possible_object_id . '][menu-item-url]" value="' . esc_url( $menu_item->url ) . '" />';
$output .= '<input type="hidden" class="menu-item-target" name="menu-item[' . $possible_object_id . '][menu-item-target]" value="' . esc_attr( $menu_item->target ) . '" />';
$output .= '<input type="hidden" class="menu-item-attr-title" name="menu-item[' . $possible_object_id . '][menu-item-attr-title]" value="' . esc_attr( $menu_item->attr_title ) . '" />';
$output .= '<input type="hidden" class="menu-item-classes" name="menu-item[' . $possible_object_id . '][menu-item-classes]" value="' . esc_attr( implode( ' ', $menu_item->classes ) ) . '" />';
$output .= '<input type="hidden" class="menu-item-xfn" name="menu-item[' . $possible_object_id . '][menu-item-xfn]" value="' . esc_attr( $menu_item->xfn ) . '" />';
}
}
Changelog
| Version | Description |
|---|---|
| 3.0.0 | Introduced. |