添加数量和排序选项到WordPress标签云小工具

在上一篇文章《添加设置选项到WordPress原有的小工具中》中,我们介绍了如何添加自定义选项到原有小工具中。文本,倡萌将实例演示添加数量和排序选项到WordPress标签云小工具,所以,确保你先看下之前教程。

通过钩子全局修改标签云小工具的参数

其实,如果只是简单修改下标签云小工具的选项,我们可以直接通过widget_tag_cloud_args 过滤器钩子来操作,具体代码示例如下:

//custom widget tag cloud
add_filter( 'widget_tag_cloud_args', 'theme_tag_cloud_args' );
function theme_tag_cloud_args( $args ){
	$newargs = array(
		'smallest'    => 8,  //最小字号
		'largest'     => 22, //最大字号
		'unit'        => 'pt',   //字号单位,可以是pt、px、em或%
		'number'      => 45,     //显示个数
		'format'      => 'flat',//列表格式,可以是flat、list或array
		'separator'   => "\n",   //分隔每一项的分隔符
		'orderby'     => 'name',//排序字段,可以是name或count
		'order'       => 'ASC', //升序或降序,ASC或DESC
		'exclude'     => null,   //结果中排除某些标签
		'include'     => null,  //结果中只包含这些标签
		'link'        => 'view', //taxonomy链接,view或edit
		'taxonomy'    => 'post_tag', //调用哪些分类法作为标签云
	);
	$return = array_merge( $args, $newargs);
	return $return;
}

第 5-16 行的代码就是各个参数的设置,根据需要修改即可,将全部代码添加到主题的 functions.php 或插件中即可。

添加选项到WordPress标签云小工具

好了,现在开始我们文本的话题,添加数量和排序选项到WordPress标签云小工具。

WordPress自带的标签云小工具的设置选项是非常简单的:

我们先来看下标签云小工具的注册代码:

<?php
/**
 * Widget API: WP_Widget_Tag_Cloud class
 *
 * @package WordPress
 * @subpackage Widgets
 * @since 4.4.0
 */

/**
 * Core class used to implement a Tag cloud widget.
 *
 * @since 2.8.0
 *
 * @see WP_Widget
 */
class WP_Widget_Tag_Cloud extends WP_Widget {

	/**
	 * Sets up a new Tag Cloud widget instance.
	 *
	 * @since 2.8.0
	 */
	public function __construct() {
		$widget_ops = array(
			'description'                 => __( 'A cloud of your most used tags.' ),
			'customize_selective_refresh' => true,
		);
		parent::__construct( 'tag_cloud', __( 'Tag Cloud' ), $widget_ops );
	}

	/**
	 * Outputs the content for the current Tag Cloud widget instance.
	 *
	 * @since 2.8.0
	 *
	 * @param array $args     Display arguments including 'before_title', 'after_title',
	 *                        'before_widget', and 'after_widget'.
	 * @param array $instance Settings for the current Tag Cloud widget instance.
	 */
	public function widget( $args, $instance ) {
		$current_taxonomy = $this->_get_current_taxonomy( $instance );

		if ( ! empty( $instance['title'] ) ) {
			$title = $instance['title'];
		} else {
			if ( 'post_tag' === $current_taxonomy ) {
				$title = __( 'Tags' );
			} else {
				$tax   = get_taxonomy( $current_taxonomy );
				$title = $tax->labels->name;
			}
		}

		$show_count = ! empty( $instance['count'] );

		$tag_cloud = wp_tag_cloud(
			/**
			 * Filters the taxonomy used in the Tag Cloud widget.
			 *
			 * @since 2.8.0
			 * @since 3.0.0 Added taxonomy drop-down.
			 * @since 4.9.0 Added the `$instance` parameter.
			 *
			 * @see wp_tag_cloud()
			 *
			 * @param array $args     Args used for the tag cloud widget.
			 * @param array $instance Array of settings for the current widget.
			 */
			apply_filters(
				'widget_tag_cloud_args',
				array(
					'taxonomy'   => $current_taxonomy,
					'echo'       => false,
					'show_count' => $show_count,
				),
				$instance
			)
		);

		if ( empty( $tag_cloud ) ) {
			return;
		}

		/** This filter is documented in wp-includes/widgets/class-wp-widget-pages.php */
		$title = apply_filters( 'widget_title', $title, $instance, $this->id_base );

		echo $args['before_widget'];
		if ( $title ) {
			echo $args['before_title'] . $title . $args['after_title'];
		}

		echo '<div class="tagcloud">';

		echo $tag_cloud;

		echo "</div>\n";
		echo $args['after_widget'];
	}

	/**
	 * Handles updating settings for the current Tag Cloud widget instance.
	 *
	 * @since 2.8.0
	 *
	 * @param array $new_instance New settings for this instance as input by the user via
	 *                            WP_Widget::form().
	 * @param array $old_instance Old settings for this instance.
	 * @return array Settings to save or bool false to cancel saving.
	 */
	public function update( $new_instance, $old_instance ) {
		$instance             = array();
		$instance['title']    = sanitize_text_field( $new_instance['title'] );
		$instance['count']    = ! empty( $new_instance['count'] ) ? 1 : 0;
		$instance['taxonomy'] = stripslashes( $new_instance['taxonomy'] );
		return $instance;
	}

	/**
	 * Outputs the Tag Cloud widget settings form.
	 *
	 * @since 2.8.0
	 *
	 * @param array $instance Current settings.
	 */
	public function form( $instance ) {
		$title = ! empty( $instance['title'] ) ? $instance['title'] : '';
		$count = isset( $instance['count'] ) ? (bool) $instance['count'] : false;
		?>
		<p>
			<label for="<?php echo $this->get_field_id( 'title' ); ?>"><?php _e( 'Title:' ); ?></label>
			<input type="text" class="widefat" id="<?php echo $this->get_field_id( 'title' ); ?>" name="<?php echo $this->get_field_name( 'title' ); ?>" value="<?php echo esc_attr( $title ); ?>" />
		</p>
		<?php
		$taxonomies       = get_taxonomies( array( 'show_tagcloud' => true ), 'object' );
		$current_taxonomy = $this->_get_current_taxonomy( $instance );

		switch ( count( $taxonomies ) ) {

			// No tag cloud supporting taxonomies found, display error message.
			case 0:
				?>
				<input type="hidden" id="<?php echo $this->get_field_id( 'taxonomy' ); ?>" name="<?php echo $this->get_field_name( 'taxonomy' ); ?>" value="" />
				<p>
					<?php _e( 'The tag cloud will not be displayed since there are no taxonomies that support the tag cloud widget.' ); ?>
				</p>
				<?php
				break;

			// Just a single tag cloud supporting taxonomy found, no need to display a select.
			case 1:
				$keys     = array_keys( $taxonomies );
				$taxonomy = reset( $keys );
				?>
				<input type="hidden" id="<?php echo $this->get_field_id( 'taxonomy' ); ?>" name="<?php echo $this->get_field_name( 'taxonomy' ); ?>" value="<?php echo esc_attr( $taxonomy ); ?>" />
				<?php
				break;

			// More than one tag cloud supporting taxonomy found, display a select.
			default:
				?>
				<p>
					<label for="<?php echo $this->get_field_id( 'taxonomy' ); ?>"><?php _e( 'Taxonomy:' ); ?></label>
					<select class="widefat" id="<?php echo $this->get_field_id( 'taxonomy' ); ?>" name="<?php echo $this->get_field_name( 'taxonomy' ); ?>">
					<?php foreach ( $taxonomies as $taxonomy => $tax ) : ?>
						<option value="<?php echo esc_attr( $taxonomy ); ?>" <?php selected( $taxonomy, $current_taxonomy ); ?>>
							<?php echo esc_html( $tax->labels->name ); ?>
						</option>
					<?php endforeach; ?>
					</select>
				</p>
				<?php
		}

		if ( count( $taxonomies ) > 0 ) {
			?>
			<p>
				<input type="checkbox" class="checkbox" id="<?php echo $this->get_field_id( 'count' ); ?>" name="<?php echo $this->get_field_name( 'count' ); ?>" <?php checked( $count, true ); ?> />
				<label for="<?php echo $this->get_field_id( 'count' ); ?>"><?php _e( 'Show tag counts' ); ?></label>
			</p>
			<?php
		}
	}

	/**
	 * Retrieves the taxonomy for the current Tag cloud widget instance.
	 *
	 * @since 4.4.0
	 *
	 * @param array $instance Current settings.
	 * @return string Name of the current taxonomy if set, otherwise 'post_tag'.
	 */
	public function _get_current_taxonomy( $instance ) {
		if ( ! empty( $instance['taxonomy'] ) && taxonomy_exists( $instance['taxonomy'] ) ) {
			return $instance['taxonomy'];
		}

		return 'post_tag';
	}
}

以上代码位于 wp-includes/widgets/class-wp-widget-tag-cloud.php 文件中。我们将57-79行的代码抽出来看一下:

		$tag_cloud = wp_tag_cloud(
			/**
			 * Filters the taxonomy used in the Tag Cloud widget.
			 *
			 * @since 2.8.0
			 * @since 3.0.0 Added taxonomy drop-down.
			 * @since 4.9.0 Added the `$instance` parameter.
			 *
			 * @see wp_tag_cloud()
			 *
			 * @param array $args     Args used for the tag cloud widget.
			 * @param array $instance Array of settings for the current widget.
			 */
			apply_filters(
				'widget_tag_cloud_args',
				array(
					'taxonomy'   => $current_taxonomy,
					'echo'       => false,
					'show_count' => $show_count,
				),
				$instance
			)
		);

代码中有一个函数 wp_tag_cloud() 用于输出标签云的内容,它里面包含了几个参数,并且有一个 widget_tag_cloud_args 过滤器钩子,这就是上文【通过钩子全局修改标签云小工具的参数】所展示的钩子和所有可用参数。

添加设置选项到标签云小工具

/**
 * 添加新选项到标签云小工具
 * @param  [type] $widget   [description]
 * @param  [type] $return   [description]
 * @param  [type] $instance [description]
 * @return [type]           [description]
 */
function cmhello_tag_cloud_new_options( $widget, $return, $instance ) {
 
    // Are we dealing with a tag_cloud widget?
    if ( 'tag_cloud' == $widget->id_base ) {
 
        ?>
            <p>
                <label for="<?php echo $widget->get_field_id('tags_number'); ?>"><?php _e( '显示数量:', 'textdomain' ); ?></label>
                <input type="text" class="widefat" id="<?php echo $widget->get_field_id('tags_number'); ?>" name="<?php echo $widget->get_field_name('tags_number'); ?>" value="<?php if (isset ( $instance['tags_number']) && $instance['tags_number']) echo esc_attr( $instance['tags_number'] ); ?>" />
            </p>
            <p>
                <label for="<?php echo $widget->get_field_id('orderbytag'); ?>"><?php _e('排序依据:', 'textdomain' ) ?></label>
                <select  class="widefat" id="<?php echo $widget->get_field_id('orderbytag'); ?>" name="<?php echo $widget->get_field_name('orderbytag'); ?>">
                    <option <?php if ( isset($instance['orderbytag']) && $instance['orderbytag'] == 'name') echo 'selected="SELECTED"'; else echo ''; ?>  value="name"><?php  echo __('名称','textdomain');?></option>
                    <option <?php if ( isset($instance['orderbytag']) && $instance['orderbytag'] == 'count') echo 'selected="SELECTED"'; else echo ''; ?> value="count"><?php echo __('数量','textdomain');?></option>
                </select>
            </p>
            <p>
                <label for="<?php echo $widget->get_field_id('ordertag'); ?>"><?php _e('排序方式:', 'textdomain' ) ?></label>
                <select  class="widefat" id="<?php echo $widget->get_field_id('ordertag'); ?>" name="<?php echo $widget->get_field_name('ordertag'); ?>">
                    <option <?php if ( isset($instance['ordertag']) && $instance['ordertag'] == 'ASC') echo 'selected="SELECTED"'; else echo ''; ?>  value="ASC"><?php  echo __('升序','textdomain');?></option>
                    <option <?php if ( isset($instance['ordertag']) && $instance['ordertag'] == 'DESC') echo 'selected="SELECTED"'; else echo ''; ?> value="DESC"><?php echo __('降序','textdomain');?></option>
                    <option <?php if ( isset($instance['ordertag']) && $instance['ordertag'] == 'RAND') echo 'selected="SELECTED"'; else echo ''; ?> value="RAND"><?php echo __('随机','textdomain');?></option>
                </select>
            </p>
        <?php
    }
}
add_filter('in_widget_form', 'cmhello_tag_cloud_new_options', 10, 3 );

我们通过 in_widget_form 过滤钩子,并在第 11 行'tag_cloud' == $widget->id_base确保新选项只适用于标签云小工具,这样我们就可以在标签云小工具中看到新的选项了:

保存标签云新选项的值

/**
 * 更新标签云新字段的值
 */
function cmhello_tag_cloud_instance($instance, $new_instance, $old_instance) {
    $instance['tags_number'] = stripslashes($new_instance['tags_number']);
    $instance['ordertag'] = stripslashes($new_instance['ordertag']);
    $instance['orderbytag'] = stripslashes($new_instance['orderbytag']);
    return $instance;
}
add_filter('widget_update_callback', 'cmhello_tag_cloud_instance', 10, 3);

通过 widget_update_callback 钩子,让小工具保存的时候,可以更新我们新增的选项设置。

修改标签云的输出

我们的新选项已经添加并可以保存,下面我们就需要将我们的新选项的值应用到标签云的参数中:

/**
 * 通过钩子去修改标签云的参数
 * @param  [type] $args     [description]
 * @param  [type] $instance [description]
 * @return [type]           [description]
 */
function cmhello_tag_cloud_args( $args, $instance){
    if(isset($instance['tags_number'])){
        $args['number'] = $instance['tags_number']; //Limit number of tags
    }
    if(isset($instance['orderbytag'])){
        $args['orderby'] = $instance['orderbytag'];
    }
    if(isset($instance['ordertag'])){
        $args['order'] = $instance['ordertag'];
    }
    return $args;
}
add_filter('widget_tag_cloud_args', 'cmhello_tag_cloud_args', 10, 2);

前文我们已经提到了 widget_tag_cloud_args 钩子,所以我们可以将新的选项通过钩子应用到标签云函数 wp_tag_cloud() 中,达到我们的目的。

完整的示例代码

以下就是我们最终用到的所有代码:

/**
 * 添加新选项到标签云小工具
 * @param  [type] $widget   [description]
 * @param  [type] $return   [description]
 * @param  [type] $instance [description]
 * @return [type]           [description]
 */
function cmhello_tag_cloud_new_options( $widget, $return, $instance ) {
 
    // Are we dealing with a tag_cloud widget?
    if ( 'tag_cloud' == $widget->id_base ) {
 
        ?>
            <p>
                <label for="<?php echo $widget->get_field_id('tags_number'); ?>"><?php _e( '显示数量:', 'textdomain' ); ?></label>
                <input type="text" class="widefat" id="<?php echo $widget->get_field_id('tags_number'); ?>" name="<?php echo $widget->get_field_name('tags_number'); ?>" value="<?php if (isset ( $instance['tags_number']) && $instance['tags_number']) echo esc_attr( $instance['tags_number'] ); ?>" />
            </p>
            <p>
                <label for="<?php echo $widget->get_field_id('orderbytag'); ?>"><?php _e('排序依据:', 'textdomain' ) ?></label>
                <select  class="widefat" id="<?php echo $widget->get_field_id('orderbytag'); ?>" name="<?php echo $widget->get_field_name('orderbytag'); ?>">
                    <option <?php if ( isset($instance['orderbytag']) && $instance['orderbytag'] == 'name') echo 'selected="SELECTED"'; else echo ''; ?>  value="name"><?php  echo __('名称','textdomain');?></option>
                    <option <?php if ( isset($instance['orderbytag']) && $instance['orderbytag'] == 'count') echo 'selected="SELECTED"'; else echo ''; ?> value="count"><?php echo __('数量','textdomain');?></option>
                </select>
            </p>
            <p>
                <label for="<?php echo $widget->get_field_id('ordertag'); ?>"><?php _e('排序方式:', 'textdomain' ) ?></label>
                <select  class="widefat" id="<?php echo $widget->get_field_id('ordertag'); ?>" name="<?php echo $widget->get_field_name('ordertag'); ?>">
                    <option <?php if ( isset($instance['ordertag']) && $instance['ordertag'] == 'ASC') echo 'selected="SELECTED"'; else echo ''; ?>  value="ASC"><?php  echo __('升序','textdomain');?></option>
                    <option <?php if ( isset($instance['ordertag']) && $instance['ordertag'] == 'DESC') echo 'selected="SELECTED"'; else echo ''; ?> value="DESC"><?php echo __('降序','textdomain');?></option>
                    <option <?php if ( isset($instance['ordertag']) && $instance['ordertag'] == 'RAND') echo 'selected="SELECTED"'; else echo ''; ?> value="RAND"><?php echo __('随机','textdomain');?></option>
                </select>
            </p>
        <?php
    }
}
add_filter('in_widget_form', 'cmhello_tag_cloud_new_options', 10, 3 );

/**
 * 更新标签云新字段的值
 */
function cmhello_tag_cloud_instance($instance, $new_instance, $old_instance) {
    $instance['tags_number'] = stripslashes($new_instance['tags_number']);
    $instance['ordertag'] = stripslashes($new_instance['ordertag']);
    $instance['orderbytag'] = stripslashes($new_instance['orderbytag']);
    return $instance;
}
add_filter('widget_update_callback', 'cmhello_tag_cloud_instance', 10, 3);

/**
 * 通过钩子去修改标签云的参数
 * @param  [type] $args     [description]
 * @param  [type] $instance [description]
 * @return [type]           [description]
 */
function cmhello_tag_cloud_args( $args, $instance){
    if(isset($instance['tags_number'])){
        $args['number'] = $instance['tags_number']; //Limit number of tags
    }
    if(isset($instance['orderbytag'])){
        $args['orderby'] = $instance['orderbytag'];
    }
    if(isset($instance['ordertag'])){
        $args['order'] = $instance['ordertag'];
    }
    return $args;
}
add_filter('widget_tag_cloud_args', 'cmhello_tag_cloud_args', 10, 2);

总结

本文提到的两种修改标签云参数的方式:

  1. 通过钩子直接修改参数:直接方便,但是不灵活,比如不同地方无法输出不同数量的标签云,也无法修改排序等
  2. 添加新选项:开发有点难(但我们已提供代码),非常灵活,每个标签云小工具都可以单独设置选项

熟悉开发的朋友可能会说,我们可以直接注销掉原有的标签云小工具,重新注册自己的,的确,这也是一种实现方式。

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倡萌

一个文科IT宅男,喜欢折腾WordPress和被它折腾 ^_^

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