WordPress菜单使用默认的Bootstrap菜单样式

主题开发 waitig 1512℃ 百度已收录 0评论

最近在开发一款新主题,打算布局使用Bootstrap来做。

但是在具体开发的时候遇到了问题,就是WordPress的菜单函数 “wp_nav_menu”默认只能定义第一层菜单的样式,并不能很好的支持第二三级菜单的自定义。

在网上搜了下解决方案,发现可以自定义Walker_Nav_Menu类来到到修改第二三级菜单样式的目的。

在此记录下方法。

一、添加样式类

添加自定义的Walker_Nav_Menu 类到主题的function文件中,或者直接新建一个wp-bootstrap-navwalker.php 文件,放在主题目录中。

以下代码来自gitbub,大家也可以直接到github上下载最新版。

项目地址:https://github.com/wp-bootstrap/wp-bootstrap-navwalker

<?php
/**
 * Created by PhpStorm.
 * User: lius
 * Date: 2017/7/15
 * Time: 12:51
 * From: 等英博客出品 http://www.waitig.com
 */
/**
 * Class Name: WP_Bootstrap_Navwalker
 * Plugin Name: WP Bootstrap Navwalker
 * Plugin URI:  https://github.com/wp-bootstrap/wp-bootstrap-navwalker
 * Description: A custom WordPress nav walker class to implement the Bootstrap 3 navigation style in a custom theme using the WordPress built in menu manager.
 * Author: Edward McIntyre - @twittem, WP Bootstrap
 * Version: 2.0.5
 * Author URI: https://github.com/wp-bootstrap
 * GitHub Plugin URI: https://github.com/wp-bootstrap/wp-bootstrap-navwalker
 * GitHub Branch: master
 * License: GPL-3.0+
 * License URI: http://www.gnu.org/licenses/gpl-3.0.txt
 */
/* Check if Class Exists. */
if ( ! class_exists( 'WP_Bootstrap_Navwalker' ) ) {
    /**
     * WP_Bootstrap_Navwalker class.
     *
     * @extends Walker_Nav_Menu
     */
    class WP_Bootstrap_Navwalker extends Walker_Nav_Menu {
        /**
         * Start Level.
         *
         * @see Walker::start_lvl()
         * @since 3.0.0
         *
         * @access public
         * @param mixed $output Passed by reference. Used to append additional content.
         * @param int   $depth (default: 0) Depth of page. Used for padding.
         * @param array $args (default: array()) Arguments.
         * @return void
         */
        public function start_lvl( &$output, $depth = 0, $args = array() ) {
            $indent = str_repeat( "\t", $depth );
            $output .= "\n$indent<ul role=\"menu\" class=\" dropdown-menu\" >\n";
        }
        /**
         * Start El.
         *
         * @see Walker::start_el()
         * @since 3.0.0
         *
         * @access public
         * @param mixed $output Passed by reference. Used to append additional content.
         * @param mixed $item Menu item data object.
         * @param int   $depth (default: 0) Depth of menu item. Used for padding.
         * @param array $args (default: array()) Arguments.
         * @param int   $id (default: 0) Menu item ID.
         * @return void
         */
        public function start_el( &$output, $item, $depth = 0, $args = array(), $id = 0 ) {
            $indent = ( $depth ) ? str_repeat( "\t", $depth ) : '';
            /**
             * Dividers, Headers or Disabled
             * =============================
             * Determine whether the item is a Divider, Header, Disabled or regular
             * menu item. To prevent errors we use the strcasecmp() function to so a
             * comparison that is not case sensitive. The strcasecmp() function returns
             * a 0 if the strings are equal.
             */
            if ( 0 === strcasecmp( $item->attr_title, 'divider' ) && 1 === $depth ) {
                $output .= $indent . '<li role="presentation" class="divider">';
            } elseif ( 0 === strcasecmp( $item->title, 'divider' ) && 1 === $depth ) {
                $output .= $indent . '<li role="presentation" class="divider">';
            } elseif ( 0 === strcasecmp( $item->attr_title, 'dropdown-header' ) && 1 === $depth ) {
                $output .= $indent . '<li role="presentation" class="dropdown-header">' . esc_attr( $item->title );
            } elseif ( 0 === strcasecmp( $item->attr_title, 'disabled' ) ) {
                $output .= $indent . '<li role="presentation" class="disabled"><a href="#">' . esc_attr( $item->title ) . '</a>';
            } else {
                $value = '';
                $class_names = $value;
                $classes = empty( $item->classes ) ? array() : (array) $item->classes;
                $classes[] = 'menu-item-' . $item->ID;
                $class_names = join( ' ', apply_filters( 'nav_menu_css_class', array_filter( $classes ), $item, $args ) );
                if ( $args->has_children ) {
                    $class_names .= ' dropdown';
                }
                if ( in_array( 'current-menu-item', $classes, true ) ) {
                    $class_names .= ' active';
                }
                $class_names = $class_names ? ' class="' . esc_attr( $class_names ) . '"' : '';
                $id = apply_filters( 'nav_menu_item_id', 'menu-item-' . $item->ID, $item, $args );
                $id = $id ? ' id="' . esc_attr( $id ) . '"' : '';
                $output .= $indent . '<li itemscope="itemscope" itemtype="https://www.schema.org/SiteNavigationElement"' . $id . $value . $class_names . '>';
                $atts = array();
                if ( empty( $item->attr_title ) ) {
                    $atts['title']  = ! empty( $item->title )   ? strip_tags( $item->title ) : '';
                } else {
                    $atts['title'] = $item->attr_title;
                }
                $atts['target'] = ! empty( $item->target ) ? $item->target : '';
                $atts['rel']    = ! empty( $item->xfn )    ? $item->xfn    : '';
                // If item has_children add atts to a.
                if ( $args->has_children && 0 === $depth ) {
                    $atts['href']           = '#';
                    $atts['data-toggle']    = 'dropdown';
                    $atts['class']          = 'dropdown-toggle';
                    $atts['aria-haspopup']  = 'true';
                } else {
                    $atts['href'] = ! empty( $item->url ) ? $item->url : '';
                }
                $atts = apply_filters( 'nav_menu_link_attributes', $atts, $item, $args );
                $attributes = '';
                foreach ( $atts as $attr => $value ) {
                    if ( ! empty( $value ) ) {
                        $value = ( 'href' === $attr ) ? esc_url( $value ) : esc_attr( $value );
                        $attributes .= ' ' . $attr . '="' . $value . '"';
                    }
                }
                $item_output = $args->before;
                /*
                 * Glyphicons/Font-Awesome
                 * ===========
                 * Since the the menu item is NOT a Divider or Header we check the see
                 * if there is a value in the attr_title property. If the attr_title
                 * property is NOT null we apply it as the class name for the glyphicon.
                 */
                if ( ! empty( $item->attr_title ) ) {
                    $pos = strpos( esc_attr( $item->attr_title ), 'glyphicon' );
                    if ( false !== $pos ) {
                        $item_output .= '<a' . $attributes . '><span class="glyphicon ' . esc_attr( $item->attr_title ) . '" aria-hidden="true"></span>&nbsp;';
                    } else {
                        $item_output .= '<a' . $attributes . '><i class="fa ' . esc_attr( $item->attr_title ) . '" aria-hidden="true"></i>&nbsp;';
                    }
                } else {
                    $item_output .= '<a' . $attributes . '>';
                }
                $item_output .= $args->link_before . apply_filters( 'the_title', $item->title, $item->ID ) . $args->link_after;
                $item_output .= ( $args->has_children && 0 === $depth ) ? ' <span class="caret"></span></a>' : '</a>';
                $item_output .= $args->after;
                $output .= apply_filters( 'walker_nav_menu_start_el', $item_output, $item, $depth, $args );
            } // End if().
        }
        /**
         * Traverse elements to create list from elements.
         *
         * Display one element if the element doesn't have any children otherwise,
         * display the element and its children. Will only traverse up to the max
         * depth and no ignore elements under that depth.
         *
         * This method shouldn't be called directly, use the walk() method instead.
         *
         * @see Walker::start_el()
         * @since 2.5.0
         *
         * @access public
         * @param mixed $element Data object.
         * @param mixed $children_elements List of elements to continue traversing.
         * @param mixed $max_depth Max depth to traverse.
         * @param mixed $depth Depth of current element.
         * @param mixed $args Arguments.
         * @param mixed $output Passed by reference. Used to append additional content.
         * @return null Null on failure with no changes to parameters.
         */
        public function display_element( $element, &$children_elements, $max_depth, $depth, $args, &$output ) {
            if ( ! $element ) {
                return; }
            $id_field = $this->db_fields['id'];
            // Display this element.
            if ( is_object( $args[0] ) ) {
                $args[0]->has_children = ! empty( $children_elements[ $element->$id_field ] ); }
            parent::display_element( $element, $children_elements, $max_depth, $depth, $args, $output );
        }
        /**
         * Menu Fallback
         * =============
         * If this function is assigned to the wp_nav_menu's fallback_cb variable
         * and a menu has not been assigned to the theme location in the WordPress
         * menu manager the function with display nothing to a non-logged in user,
         * and will add a link to the WordPress menu manager if logged in as an admin.
         *
         * @param array $args passed from the wp_nav_menu function.
         */
        public static function fallback( $args ) {
            if ( current_user_can( 'edit_theme_options' ) ) {
                /* Get Arguments. */
                $container = $args['container'];
                $container_id = $args['container_id'];
                $container_class = $args['container_class'];
                $menu_class = $args['menu_class'];
                $menu_id = $args['menu_id'];
                if ( $container ) {
                    echo '<' . esc_attr( $container );
                    if ( $container_id ) {
                        echo ' id="' . esc_attr( $container_id ) . '"';
                    }
                    if ( $container_class ) {
                        echo ' class="' . sanitize_html_class( $container_class ) . '"'; }
                    echo '>';
                }
                echo '<ul';
                if ( $menu_id ) {
                    echo ' id="' . esc_attr( $menu_id ) . '"'; }
                if ( $menu_class ) {
                    echo ' class="' . esc_attr( $menu_class ) . '"'; }
                echo '>';
                echo '<li><a href="' . esc_url( admin_url( 'nav-menus.php' ) ) . '" title="">' . esc_attr( 'Add a menu', '' ) . '</a></li>';
                echo '</ul>';
                if ( $container ) {
                    echo '</' . esc_attr( $container ) . '>'; }
            }
        }
    }
} // End if().

接下来进行第二步

二、引入代码文件

如果你是新建文件的方式,则需要在function文件中引入那个文件,如果你是直接将代码写在function文件中,则不需要进行这步操作。

/**
 * Class BS_Walker_Nav_Menu
 * 使菜单使用Boostrap
 * From: 等英博客出品 http://www.waitig.com
 */
require_once 'wp-bootstrap-navwalker.php';

三、输出菜单样式

在输出菜单时使用自定的WP_Bootstrap_Navwalker样式类

官方推荐的样式:

<nav class="navbar navbar-default" role="navigation">
  <div class="container-fluid">
    <!-- Brand and toggle get grouped for better mobile display -->
    <div class="navbar-header">
      <button type="button" class="navbar-toggle" data-toggle="collapse" data-target="#bs-example-navbar-collapse-1">
        <span class="sr-only">Toggle navigation</span>
        <span class="icon-bar"></span>
        <span class="icon-bar"></span>
        <span class="icon-bar"></span>
      </button>
      <a class="navbar-brand" href="<?php echo home_url(); ?>">
                <?php bloginfo('name'); ?>
            </a>
    </div>

        <?php
            wp_nav_menu( array(
                'menu'              => 'primary',
                'theme_location'    => 'primary',
                'depth'             => 2,
                'container'         => 'div',
                'container_class'   => 'collapse navbar-collapse',
                'container_id'      => 'bs-example-navbar-collapse-1',
                'menu_class'        => 'nav navbar-nav',
                'fallback_cb'       => 'WP_Bootstrap_Navwalker::fallback',
                'walker'            => new WP_Bootstrap_Navwalker())
            );
        ?>
    </div>
</nav>

不出意外的话,这样WordPress的菜单就可以使用bootstrap默认的菜单样式了,如果你想自定义其样式的话,可以重写其中的样式。

如图所示:

image


本文由【waitig】发表在等英博客
本文固定链接:WordPress菜单使用默认的Bootstrap菜单样式
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