Add Filter to Filterbar Example

/**
 * Quick example of adding a custom filter
 * A simple copy and paste of the existing Category filter
 * Refer to the last line for how it adds itself to the interface
 * Find this new filter in: WP Admin > Events > Settings > Filterbar
 * Docs for TribeEventsFilter: http://docs.tri.be/Filter-Bar/class-TribeEventsFilter.html
 */
class TribeEventsFilter_Custom extends TribeEventsFilter {
    public $type = 'select';

    public function get_admin_form() {
        $title = $this->get_title_field();
        $type = $this->get_type_field();
        return $title.$type;
    }

    protected function get_type_field() {
        $name = $this->get_admin_field_name('type');
        $field = sprintf( __( 'Type: %s %s', 'tribe-events-filter-view' ),
            sprintf( '<label><input type="radio" name="%s" value="select" %s /> %s</label>',
                $name,
                checked( $this->type, 'select', false ),
                __( 'Dropdown', 'tribe-events-filter-view' )
            ),
            sprintf( '<label><input type="radio" name="%s" value="checkbox" %s /> %s</label>',
                $name,
                checked( $this->type, 'checkbox', false ),
                __( 'Checkboxes', 'tribe-events-filter-view' )
            )
        );
        return '<div class="tribe_events_active_filter_type_options">'.$field.'</div>';
    }

    protected function get_values() {
        $event_categories = array();
        $event_categories_term = get_terms( TribeEvents::TAXONOMY, array( 'orderby' => 'name', 'order' => 'DESC' ) );
        $event_categories_by_id = array();
        foreach( $event_categories_term as $term ) {
            $event_categories_by_id[$term->term_id] = $term;
        }
        $event_categories_by_id_reverse = array_reverse( $event_categories_by_id );
        $parents = array( '0' );
        while ( !empty( $parents ) ) {
            $parents_copy = $parents;
            foreach ( $event_categories_by_id_reverse as $term ) {
                if ( in_array( $term->parent, $parents_copy ) ) {
                    $parents[] = $term->term_id;
                    unset( $event_categories_by_id[$term->term_id] );
                    $event_categories_by_id = TribeEvents::array_insert_after_key( $term->parent, $event_categories_by_id, array( $term->term_id => $term ) );
                }
            }
            $parents = array_diff( $parents, $parents_copy );
        }
        $child_spacer = '&nbsp;&nbsp;';
        foreach( $event_categories_by_id as $cat ) {
            $child_depth = 0;
            $parent_id = $cat->parent;
            while ( $parent_id != 0 ) {
                $child_depth++;
                $parent_id = $event_categories_by_id[$parent_id]->parent;
            }
            $child_indent = str_repeat($child_spacer, $child_depth);
            $event_categories[] = array(
                'name' => $child_indent . $cat->name,
                'value' => $cat->term_id,
                'data' => array(
                    'slug' => $cat->slug,
                ),
            );
        }
        return $event_categories;
    }

    protected function setup_query_args() {
        $this->queryArgs = array( 'tax_query' => array( array(
            'taxonomy' => TribeEvents::TAXONOMY,
            'field' => 'id',
            'terms' => $this->currentValue,
            'include_children' => false,
        ) ) );
    }

}

// This adds our new filter to the Filterbar options
// Invokes TribeEventsFilter::__construct($name, $slug);
$taxonomy_example = new TribeEventsFilter_Custom('Taxonomy', 'taxonomy_filter');