我认为整个问题是您试图使用默认的walker，但通过在walker字段中声明它，告诉wordpress您试图加载自定义walker，如果保留为空，则默认情况下会加载wp walker。
两个选项：
1/更改\'walker\' => new Walker_Nav_Menu() to \'walker\' => \'\' 默认情况下称为。
2/将声明编辑为新名称，如：new themeslug\\u Walker\\u Nav\\u Menu（），然后将以下内容添加到函数中。php：
class themeslug_walker_nav_menu extends Walker_Nav_Menu {
// add classes to ul sub-menus
function start_lvl( &$output, $depth ) {
// depth dependent classes
$indent = ( $depth > 0 ? str_repeat( "\\t", $depth ) : \'\' ); // code indent
$display_depth = ( $depth + 1); // because it counts the first submenu as 0
$classes = array(
\'sub-menu\',
( $display_depth % 2 ? \'menu-odd\' : \'menu-even\' ),
( $display_depth >=2 ? \'sub-sub-menu\' : \'\' ),
\'menu-depth-\' . $display_depth
);
$class_names = implode( \' \', $classes );
// build html
$output .= "\\n" . $indent . \'\' . "\\n";
}
// add main/sub classes to li\'s and links
function start_el( &$output, $item, $depth, $args ) {
global $wp_query;
$indent = ( $depth > 0 ? str_repeat( "\\t", $depth ) : \'\' ); // code indent
// depth dependent classes
$depth_classes = array(
( $depth == 0 ? \'main-menu-item\' : \'sub-menu-item\' ),
( $depth >=2 ? \'sub-sub-menu-item\' : \'\' ),
( $depth % 2 ? \'menu-item-odd\' : \'menu-item-even\' ),
\'menu-item-depth-\' . $depth
);
$depth_class_names = esc_attr( implode( \' \', $depth_classes ) );
// passed classes
$classes = empty( $item->classes ) ? array() : (array) $item->classes;
$class_names = esc_attr( implode( \' \', apply_filters( \'nav_menu_css_class\', array_filter( $classes ), $item ) ) );
// build html
$output .= $indent . \'ID . \'" class="\' . $depth_class_names . \' \' . $class_names . \'">\';
// link attributes
$attributes = ! empty( $item->attr_title ) ? \' title="\' . esc_attr( $item->attr_title ) .\'"\' : \'\';
$attributes .= ! empty( $item->target ) ? \' target="\' . esc_attr( $item->target ) .\'"\' : \'\';
$attributes .= ! empty( $item->xfn ) ? \' rel="\' . esc_attr( $item->xfn ) .\'"\' : \'\';
$attributes .= ! empty( $item->url ) ? \' href="\' . esc_attr( $item->url ) .\'"\' : \'\';
$attributes .= \' class="menu-link \' . ( $depth > 0 ? \'sub-menu-link\' : \'main-menu-link\' ) . \'"\';
$item_output = sprintf( \'%1$s%3$s%4$s%5$s%6$s\',
$args->before,
$attributes,
$args->link_before,
apply_filters( \'the_title\', $item->title, $item->ID ),
$args->link_after,
$args->after
);
// build html
$output .= apply_filters( \'walker_nav_menu_start_el\', $item_output, $item, $depth, $args );
}
}
参见法典，其解释相当清楚。
