Displaying a list of column headers from an arbitrary number of columns.

display-column-headers.php

    /*
     * Display column headers for the user-selected array of columns.
     * 
     * @var str $query:     The query array.
     */
    public function displayColumnHeaders( $query ) {
        $headers        = '';
        $sort           = $query['sort'];
        $direction      = $query['direction'];
        $arrow          = sprintf('fa fa-sort-%s', $direction);
        $this->Paginator->options([
            'defaultModel'  => 'Invoices'
        ]);
        foreach( $this->activeColumns as $key=>$meta ) :
            if(in_array($meta['sort_index'], $this->noSort)) :
                $content    = $meta['label'];
            elseif($sort==$meta['sort_index']) :
                $content    = $this->Paginator->sort(
                    $meta['sort_index'],
                    sprintf(
                        '<i class="%s sort-arrow">&nbsp;</i><span class="sort-text">%s</span>',
                        $arrow,
                        $meta['label']
                    ),
                    [
                        'escape'    => false,
                        'direction' => ($direction == 'ASC') ? 'DESC' : 'ASC'
                    ]
                );
            else :
                $content    = $this->Paginator->sort( $meta['sort_index'], $meta['label'] );
            endif;
            $headers    .= sprintf(
                '<th scope="col %s">%s</th>',
                $key,
                $content
            );
        endforeach;
        return $headers;
    }