If you’ve used taxonomy field type, you will see it has an option to display options in a checkbox / select tree. When users select a parent item, it will show children item. It’s quite a nice feature for users. But how to do that with normal checkbox list or select field types?
The answer is simple: it’s already built-in the Meta Box plugin. And here is the sample code:
add_filter( 'rwmb_meta_boxes', function ( $meta_boxes ) {
$meta_boxes[] = array(
'title' => 'Test',
'fields' => array(
array(
'type' => 'select_tree', // or checkbox_list
'id' => 'cb',
'name' => 'Hierarchical checkboxes',
'options' => array(
array( 'value' => 'value1', 'label' => 'label 1' ),
array( 'value' => 'value2', 'label' => 'label 2' ),
array( 'value' => 'sub1', 'label' => 'Sub 1', 'parent' => 'value1' ),
array( 'value' => 'sub2', 'label' => 'Sub 2', 'parent' => 'value1' ),
),
'flatten' => false,
),
),
);
return $meta_boxes;
} );
To enable select/checkbox tree, you need to:
- Set the option in format of
array( 'value' => 'Your value', 'label' => 'Your label' ), e.g. no more short type of'value' => 'Label'anymore. - For child items, please add
'parent' => 'parent_value' - Set
'flatten' => falsefor the field - Set the field type
checkbox_listif you want a checkbox tree orselect_treeif you want a select tree.