Revised

multiple-taxonomies-acf-field.php

<?php
add_action( 'init', function() {

	if ( class_exists( 'AcfFieldMultipleCategories' ) || ! class_exists( 'acf_field_taxonomy' ) ) {
		return;
	}

	/**
	 * Class for ACF field.
	 */
	class AcfFieldMultipleCategories extends acf_field_taxonomy {


		/**
		 * This function will setup the field type data.
		 *
		 *  @type    function
		 *  @date    5/03/2014
		 *  @since   5.0.0
		 */
		function initialize() {
			parent::initialize();

			// Vars.
			$this->name     = 'multiple_taxonomies';
			$this->label    =  __( 'Multiple Taxonomies' );
			$this->defaults = array(
				'taxonomies'    => array( 'category' ),
				'field_type'    => 'select',
				'multiple'      => 0,
				'allow_null'    => 0,
				'return_format' => 'id',
				'add_term'      => 0,
				'load_terms'    => 0,
				'save_terms'    => 0,
				'ui'            => 1,
				'ajax'          => 1,
				'ajax_action'   => 'acf/fields/multiple_taxonomies/query',
				'placeholder'   => 'Select Term',
			);

			// ajax
			add_action( 'wp_ajax_acf/fields/multiple_taxonomies/query',        array( $this, 'ajax_query' ) );
			add_action( 'wp_ajax_nopriv_acf/fields/multiple_taxonomies/query', array( $this, 'ajax_query' ) );

			// Extra.
			add_filter( 'acf/field_wrapper_attributes', array( $this, 'wrapper_attributes' ), 10, 2 );

		}

		public function wrapper_attributes( $wrapper, $field ) {
			if ( 'multiple_taxonomies' === $field['type'] ) {
				$wrapper['class']    .= ' acf-field-taxonomy';
				$wrapper['data-type'] = 'taxonomy';
			}
			return $wrapper;
		}

		/**
		 *  This function will return an array of data formatted for use in a select2 AJAX response.
		 *
		 *  @type    function
		 *  @date    15/10/2014
		 *  @since   5.0.9
		 *
		 *  @param   array $options Options.
		 *  @return  array $r Choices.
		 */
		function get_ajax_query( $options = array() ) {

			// Defaults.
			$options = acf_parse_args( $options, array(
				'post_id'   => 0,
				's'         => '',
				'field_key' => '',
				'paged'     => 0,
			) );

			// Load field.
			$field = acf_get_field( $options['field_key'] );

			if ( ! $field ) {
				return false;
			}

			// Vars.
			$results       = array();
			$args          = array();
			$limit         = 20;
			$offset        = 20 * ( $options['paged'] - 1 );

			// Hide Empty.
			$args['hide_empty'] = false;
			$args['number']     = $limit;
			$args['offset']     = $offset;

			// Pagination
			// Don't bother for hierarchial terms, we will need to load all terms anyway.
			if ( $options['s'] ) {
				$args['search'] = $options['s'];
			}

			// Get terms.
			$terms = get_terms( $field['taxonomies'], $args );

			/// append to r
			foreach( $terms as $term ) {

				// add to json
				$results[] = array(
					'id'	=> $term->term_id,
					'text'	=> $this->get_term_title( $term, $field, $options['post_id'] )
				);

			}

			// vars
			$response = array(
				'results'	=> $results,
				'limit'		=> $limit
			);

			// Return.
			return $response;

		}

		/**
		 *  This filter is appied to the $value after it is loaded from the db.
		 *
		 *  @type    filter
		 *  @since   3.6
		 *  @date    23/01/13
		 *
		 *  @param   string $value The value found in the database.
		 *  @param   int    $post_id The post ID from which the value was loaded from.
		 *  @param   array  $field The field array holding all the field options.
		 *
		 *  @return  $value - the value to be saved in te database
		 */
		function load_value( $value, $post_id, $field ) {
			// Return.
			return $value;
		}

		/**
		 *  Create the HTML interface for your field.
		 *
		 *  @type    action
		 *  @since   3.6
		 *  @date    23/01/13
		 *
		 *  @param   array $field An array holding all the field's data.
		 */
		function render_field( $field ) {

			// Force value to arra.
			$field['value']    = acf_get_array( $field['value'] );
			$field['multiple'] = 0;

			// Vars.
			$div = array(
				'class'           => 'acf-taxonomy-field acf-soh',
				'data-save'       => $field['save_terms'],
				'data-type'       => $field['field_type'],
				'data-taxonomies' => $field['taxonomies'],
				'data-ftype'      => 'select',
			);

			?>
			<div <?php acf_esc_attr_e( $div ); ?>>
				<?php $this->render_field_select( $field ); ?>
			</div>
			<?php
		}


		/**
		 *  Create the HTML interface for your field/
		 *
		 *  @type    action
		 *  @since   3.6
		 *  @date    23/01/13
		 *
		 *  @param   array $field An array holding all the field's data.
		 */
		function render_field_select( $field ) {

			// Change Field into a select.
			$field['type']    = 'select';
			$field['ui']      = 1;
			$field['ajax']    = 1;
			$field['choices'] = array();

			$choices = array();

			if ( count( $field['value'] ) >= 1 ) {
				$term                          = get_term_by_id( $field['value'][0] );
				$choices[ $field['value'][0] ] = $term->name;
			}

			$field['choices'] = $choices;

			acf_render_field( $field );

		}


		/**
		 *  Create extra options for your field. This is rendered when editing a field.
		 *  The value of $field['name'] can be used (like bellow) to save extra data to the $field
		 *
		 *  @type    action
		 *  @since   3.6
		 *  @date    23/01/13
		 *
		 *  @param   array $field An array holding all the field's data.
		 */
		function render_field_settings( $field ) {

			$taxes = acf_get_taxonomies();
			// Default value.
			acf_render_field_setting( $field, array(
				'label'        => __( 'Taxonomies' ),
				'instructions' => __( 'Select the taxonomies to be displayed' ),
				'type'         => 'select',
				'name'         => 'taxonomies',
				'multiple'     => 1,
				'ui'           => 1,
				'choices'      => array_combine( $taxes, $taxes ),
			) );

			// Allow null.
			acf_render_field_setting( $field, array(
				'label'        => __( 'Allow Null?', 'acf' ),
				'instructions' => '',
				'name'         => 'allow_null',
				'type'         => 'true_false',
				'ui'			=> 1,
				'conditions'	=> array(
					'field'		=> 'field_type',
					'operator'	=> '!=',
					'value'		=> 'checkbox'
				)
			) );

			// Save terms.
			acf_render_field_setting( $field, array(
				'label'        => __( 'Save Terms', 'acf' ),
				'instructions' => __( 'Connect selected terms to the post', 'acf' ),
				'type'         => 'radio',
				'name'         => 'save_terms',
				'type'         => 'true_false',
				'ui'           => 1,
			) );

			// Load terms.
			acf_render_field_setting( $field, array(
				'label'        => __( 'Load Terms', 'acf' ),
				'instructions' => __( 'Load value from posts terms', 'acf' ),
				'name'         => 'load_terms',
				'type'         => 'true_false',
				'ui'           => 1,
			) );

			// Return format.
			acf_render_field_setting( $field, array(
				'label'        => __( 'Return Value', 'acf' ),
				'instructions' => '',
				'type'         => 'radio',
				'name'         => 'return_format',
				'choices'      => array(
					'object' => __( 'Term Object', 'acf' ),
					'id'     => __( 'Term ID', 'acf' ),
				),
				'layout'       => 'horizontal',
			) );

		}
	}

	acf_register_field_type( 'AcfFieldMultipleCategories' );

} );