WordPress 添加可重复使用的自定义metabox 字段

所谓 WordPress metabox，就是类似文章编辑框下面 WP 自带的自定义字段的设置面板，通过 add_meta_box() 可以添加自定义面板，方便地输入相关信息，并在前端调用实现一些功能。

基本的面板添加代码网上很多，本文分享两个可重复使用的自定义 metabox 字段面板。

代码一

预设两个字段，可重复添加，并以组数存储在数据库 wp_postmeta 表中
WordPress 添加可重复使用的自定义metabox 字段

add_action('admin_init', 'add_meta_boxes', 1);
function add_meta_boxes() {
add_meta_box( 'repeatable-fields', 'Audio Playlist', 'repeatable_meta_box_display', 'post', 'normal', 'high');
}
function repeatable_meta_box_display() {
global $post;
$repeatable_fields = get_post_meta($post->ID, 'repeatable_fields', true);
wp_nonce_field( 'repeatable_meta_box_nonce', 'repeatable_meta_box_nonce' );
?>
<script type="text/javascript">
jQuery(document).ready(function($) {
$('.metabox_submit').click(function(e) {
e.preventDefault();
$('#publish').click();
});
$('#add-row').on('click', function() {
var row = $('.empty-row.screen-reader-text').clone(true);
row.removeClass('empty-row screen-reader-text');
row.insertBefore('#repeatable-fieldset-one tbody>tr:last');
return false;
});
$('.remove-row').on('click', function() {
$(this).parents('tr').remove();
return false;
});
$('#repeatable-fieldset-one tbody').sortable({
opacity: 0.6,
revert: true,
cursor: 'move',
handle: '.sort'
});
});
</script>
<table id="repeatable-fieldset-one" width="100%">
<thead>
<tr>
<th width="2%"></th>
<th width="30%">Name</th>
<th width="60%">URL</th>
<th width="2%"></th>
</tr>
</thead>
<tbody>
<?php
if ( $repeatable_fields ) :
foreach ( $repeatable_fields as $field ) {
?>
<tr>
<td><a class="button remove-row" href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >-</a></td>
<td><input type="text" class="widefat" name="name[]" value="<?php if($field['name'] != '') echo esc_attr( $field['name'] ); ?>" /></td>
<td><input type="text" class="widefat" name="url[]" value="<?php if ($field['url'] != '') echo esc_attr( $field['url'] ); else echo 'http://'; ?>" /></td>
<td><a class="sort">|||</a></td>
</tr>
<?php
}
else :
// show a blank one
?>
<tr>
<td><a class="button remove-row" href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >-</a></td>
<td><input type="text" class="widefat" name="name[]" /></td>
<td><input type="text" class="widefat" name="url[]" value="http://" /></td>
<td><a class="sort">|||</a></td>
</tr>
<?php endif; ?>
<tr class="empty-row screen-reader-text">
<td><a class="button remove-row" href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >-</a></td>
<td><input type="text" class="widefat" name="name[]" /></td>
<td><input type="text" class="widefat" name="url[]" value="http://" /></td>
<td><a class="sort">|||</a></td>
</tr>
</tbody>
</table>
<p><a id="add-row" class="button" href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >Add another</a>
<input type="submit" class="metabox_submit" value="Save" />
</p>
<?php
}
add_action('save_post', 'repeatable_meta_box_save');
function repeatable_meta_box_save($post_id) {
if ( ! isset( $_POST['repeatable_meta_box_nonce'] ) ||
! wp_verify_nonce( $_POST['repeatable_meta_box_nonce'], 'repeatable_meta_box_nonce' ) )
return;
if (defined('DOING_AUTOSAVE') && DOING_AUTOSAVE)
return;
if (!current_user_can('edit_post', $post_id))
return;
$old = get_post_meta($post_id, 'repeatable_fields', true);
$new = array();
$names = $_POST['name'];
$urls = $_POST['url'];
$count = count( $names );
for ( $i = 0; $i < $count; $i++ ) {
if ( $names[$i] != '' ) :
$new[$i]['name'] = stripslashes( strip_tags( $names[$i] ) );
if ( $urls[$i] == 'http://' )
$new[$i]['url'] = '';
else
$new[$i]['url'] = stripslashes( $urls[$i] ); // and however you want to sanitize
endif;
}
if ( !empty( $new ) && $new != $old )
update_post_meta( $post_id, 'repeatable_fields', $new );
elseif ( empty($new) && $old )
delete_post_meta( $post_id, 'repeatable_fields', $old );
}

前端调用

<?php $repeatable_fields = get_post_meta( $post->ID, 'repeatable_fields', true ); if ( $repeatable_fields ) : ?>
<div class="list">
<?php foreach ( $repeatable_fields as $field ) { ?>
<div class="row">
<?php if( $field['name'] != '' ) echo '<span class="field">'. esc_attr( $field['name'] ) . '</span>'; ?>
<?php if( $field['url'] != '' ) echo '<span class="field">'. esc_attr( $field['url'] ) . '</span>'; ?>
</div>
<?php } ?>
</div>
<?php endif; ?>

代码二

在上面的基础上，附加了下拉选项字段。

function hhs_get_sample_options() {
$options = array (
'Option 1' => 'option1',
'Option 2' => 'option2',
'Option 3' => 'option3',
'Option 4' => 'option4',
);
return $options;
}
add_action('admin_init', 'hhs_add_meta_boxes', 1);
function hhs_add_meta_boxes() {
add_meta_box( 'repeatable-fields', 'Repeatable Fields', 'hhs_repeatable_meta_box_display', 'post', 'normal', 'default');
}
function hhs_repeatable_meta_box_display() {
global $post;
$repeatable_fields = get_post_meta($post->ID, 'repeatable_fields', true);
$options = hhs_get_sample_options();
wp_nonce_field( 'hhs_repeatable_meta_box_nonce', 'hhs_repeatable_meta_box_nonce' );
?>
<script type="text/javascript">
jQuery(document).ready(function( $ ){
$( '#add-row' ).on('click', function() {
var row = $( '.empty-row.screen-reader-text' ).clone(true);
row.removeClass( 'empty-row screen-reader-text' );
row.insertBefore( '#repeatable-fieldset-one tbody>tr:last' );
return false;
});
$( '.remove-row' ).on('click', function() {
$(this).parents('tr').remove();
return false;
});
});
</script>
<table id="repeatable-fieldset-one" width="100%">
<thead>
<tr>
<th width="40%">Name</th>
<th width="12%">Select</th>
<th width="40%">URL</th>
<th width="8%"></th>
</tr>
</thead>
<tbody>
<?php
if ( $repeatable_fields ) :
foreach ( $repeatable_fields as $field ) {
?>
<tr>
<td><input type="text" class="widefat" name="name[]" value="<?php if($field['name'] != '') echo esc_attr( $field['name'] ); ?>" /></td>
<td>
<select name="select[]">
<?php foreach ( $options as $label => $value ) : ?>
<option value="<?php echo $value; ?>"<?php selected( $field['select'], $value ); ?>><?php echo $label; ?></option>
<?php endforeach; ?>
</select>
</td>
<td><input type="text" class="widefat" name="url[]" value="<?php if ($field['url'] != '') echo esc_attr( $field['url'] ); else echo 'http://'; ?>" /></td>
<td><a class="button remove-row" href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >Remove</a></td>
</tr>
<?php
}
else :
// show a blank one
?>
<tr>
<td><input type="text" class="widefat" name="name[]" /></td>
<td>
<select name="select[]">
<?php foreach ( $options as $label => $value ) : ?>
<option value="<?php echo $value; ?>"><?php echo $label; ?></option>
<?php endforeach; ?>
</select>
</td>
<td><input type="text" class="widefat" name="url[]" value="http://" /></td>
<td><a class="button remove-row" href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >Remove</a></td>
</tr>
<?php endif; ?>
<tr class="empty-row screen-reader-text">
<td><input type="text" class="widefat" name="name[]" /></td>
<td>
<select name="select[]">
<?php foreach ( $options as $label => $value ) : ?>
<option value="<?php echo $value; ?>"><?php echo $label; ?></option>
<?php endforeach; ?>
</select>
</td>
<td><input type="text" class="widefat" name="url[]" value="http://" /></td>
<td><a class="button remove-row" href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >Remove</a></td>
</tr>
</tbody>
</table>
<p><a id="add-row" class="button" href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >Add another</a></p>
<?php
}
add_action('save_post', 'hhs_repeatable_meta_box_save');
function hhs_repeatable_meta_box_save($post_id) {
if ( ! isset( $_POST['hhs_repeatable_meta_box_nonce'] ) ||
! wp_verify_nonce( $_POST['hhs_repeatable_meta_box_nonce'], 'hhs_repeatable_meta_box_nonce' ) )
return;
if (defined('DOING_AUTOSAVE') && DOING_AUTOSAVE)
return;
if (!current_user_can('edit_post', $post_id))
return;
$old = get_post_meta($post_id, 'repeatable_fields', true);
$new = array();
$options = hhs_get_sample_options();
$names = $_POST['name'];
$selects = $_POST['select'];
$urls = $_POST['url'];
$count = count( $names );
for ( $i = 0; $i < $count; $i++ ) {
if ( $names[$i] != '' ) :
$new[$i]['name'] = stripslashes( strip_tags( $names[$i] ) );
if ( in_array( $selects[$i], $options ) )
$new[$i]['select'] = $selects[$i];
else
$new[$i]['select'] = '';
if ( $urls[$i] == 'http://' )
$new[$i]['url'] = '';
else
$new[$i]['url'] = stripslashes( $urls[$i] ); // and however you want to sanitize
endif;
}
if ( !empty( $new ) && $new != $old )
update_post_meta( $post_id, 'repeatable_fields', $new );
elseif ( empty($new) && $old )
delete_post_meta( $post_id, 'repeatable_fields', $old );
}

前端调用

<?php $repeatable_fields = get_post_meta( $post->ID, 'repeatable_fields', true ); if ( $repeatable_fields ) : ?>
<div class="list">
<?php foreach ( $repeatable_fields as $field ) { ?>
<div class="row">
<?php if( $field['name'] != '' ) echo '<span class="field">'. esc_attr( $field['name'] ) . '</span>'; ?>
<?php if( $field['select'] != '' ) echo '<span class="field">'. esc_attr( $field['select'] ) . '</span>'; ?>
<?php if( $field['url'] != '' ) echo '<span class="field">'. esc_attr( $field['url'] ) . '</span>'; ?>
</div>
<?php } ?>
</div>
<?php endif; ?>