如何在wordpress的自定义元数据库中添加文章类别

Question

我想在下拉选择框中加载我的帖子类别我如何做到这一点请帮助我我是编程新手：

这是我创建自定义元框的代码，现在在这里的类别描述中，我希望它加载下拉菜单中的所有帖子类别：代码的输出显示在所附的图像中。

//Start: Adding custom metaboxes
class leaderboarddetailMetabox {
private $screen = array(
'ld-leaderboard',
);
private $meta_fields = array(
array(
'label' => 'Number of Students',
'id' => 'numberofstudent_81418',
'type' => 'number',
),
array(
'label' => 'Select Point Type',
'id' => 'selectpointtype_39141',
'type' => 'select',
'options' => array(
'Select',
'Int',
'Float',
'String',
),
),
array(
'label' => 'Category',
'id' => 'category_59112',
'type' => 'select',
'options' => array(
'Select',
'Course',
'Lesson',
'Topic',
'Quiz',
'Category',
),
),
array(
'label' => 'Time',
'id' => 'time_93126',
'type' => 'date',
),
array(
'label' => 'Shortcode',
'id' => 'shortcode_85946',
'type' => 'text',
'readonly' => true,
),
);
public function __construct() {
add_action( 'add_meta_boxes', array( $this, 'add_meta_boxes' ) );
add_action( 'save_post', array( $this, 'save_fields' ) );
}
// show meta boxes on admin page
public function add_meta_boxes() {
foreach ( $this->screen as $single_screen ) {
add_meta_box(
'leaderboarddetail',
__( 'leader board detail', 'textdomain' ),
array( $this, 'meta_box_callback' ),
$single_screen,
'advanced',
'default'
);
}
}
public function meta_box_callback( $post ) {
wp_nonce_field( 'leaderboarddetail_data', 'leaderboarddetail_nonce' );
$this->field_generator( $post );
}
public function field_generator( $post ) {
$output = '';
foreach ( $this->meta_fields as $meta_field ) {
$label = '<label for="' . $meta_field['id'] . '">' . $meta_field['label'] . '</label>';
$meta_value = get_post_meta( $post->ID, $meta_field['id'], true );
if ( empty( $meta_value ) ) {
$meta_value = $meta_field['default']; }
switch ( $meta_field['type'] ) {
case 'select':
$input = sprintf(
'<select id="%s" name="%s">',
$meta_field['id'],
$meta_field['id']
);
foreach ( $meta_field['options'] as $key => $value ) {
$meta_field_value = !is_numeric( $key ) ? $key : $value;
$input .= sprintf(
'<option %s value="%s">%s</option>',
$meta_value === $meta_field_value ? 'selected' : '',
$meta_field_value,
$value
);
}
$input .= '</select>';
break;
default:
$input = sprintf(
'<input %s id="%s" name="%s" type="%s" value="%s" %s >',
$meta_field['type'] !== 'color' ? 'style="width: 100%"' : '',
$meta_field['id'],
$meta_field['id'],
$meta_field['type'],
$meta_value,
$meta_field['readonly'] ? "readonly" : ""
);
}
$output .= $this->format_rows( $label, $input );
}
echo '<table class="form-table"><tbody>' . $output . '</tbody></table>';
}
public function format_rows( $label, $input ) {
return '<tr><th>'.$label.'</th><td>'.$input.'</td></tr>';
}
// save custom field data to databse and in the field 
public function save_fields( $post_id ) {
if ( ! isset( $_POST['leaderboarddetail_nonce'] ) )
return $post_id;
$nonce = $_POST['leaderboarddetail_nonce'];
if ( !wp_verify_nonce( $nonce, 'leaderboarddetail_data' ) )
return $post_id;
if ( defined( 'DOING_AUTOSAVE' ) && DOING_AUTOSAVE )
return $post_id;
foreach ( $this->meta_fields as $meta_field ) {
if ( isset( $_POST[ $meta_field['id'] ] ) ) {
switch ( $meta_field['type'] ) {
case 'email':
$_POST[ $meta_field['id'] ] = sanitize_email( $_POST[ $meta_field['id'] ] );
break;
case 'text':
$_POST[ $meta_field['id'] ] = sanitize_text_field( $_POST[ $meta_field['id'] ] );
break;
}
update_post_meta( $post_id, $meta_field['id'], $_POST[ $meta_field['id'] ] );
} else if ( $meta_field['type'] === 'checkbox' ) {
update_post_meta( $post_id, $meta_field['id'], '0' );
}
// generate shortcode and save
if( $meta_field['id'] == 'shortcode_85946' ) {
// update meta
update_post_meta( $post_id, $meta_field['id'], "[custom-shortcode id=" . $post_id . "]");
}
}
}
}
if (class_exists('leaderboarddetailMetabox')) {
new leaderboarddetailMetabox;
};
?>

Answer 1

要获得类别，可以使用get_terms()或get_categories()

如果您使用的是默认的帖子类别，而不是自定义分类法，那么您的功能应该类似于：

$categories = get_categories( array(
'orderby'    => 'name',
'order'      => 'ASC',
'hide_empty' => false
) );
$categoryNames = array();
if (is_array($categories)) {
foreach ($categories as $category) {
array_push($categoryNames, $category->name);
}
}

这将更改您的$meta_fields变量如下：

private $meta_fields = array(
array(
'label' => 'Number of Students',
'id' => 'numberofstudent_81418',
'type' => 'number',
),
array(
'label' => 'Select Point Type',
'id' => 'selectpointtype_39141',
'type' => 'select',
'options' => array(
'Select',
'Int',
'Float',
'String',
),
),
array(
'label' => 'Category',
'id' => 'category_59112',
'type' => 'select',
'options' => $categoryNames
),
array(
'label' => 'Time',
'id' => 'time_93126',
'type' => 'date',
),
array(
'label' => 'Shortcode',
'id' => 'shortcode_85946',
'type' => 'text',
'readonly' => true,
),
);