Get values of other custom fields in field layout override

Question

1. I am using a repeatable custom field for articles in Joomla! 3.9.16 with an alternative layout (override) of com_fields/layouts/field/render.php and an override of plugins/fields/repeatable/tmpl/repeatable.php to show the fields content in columns "After Display". This is working fine.

2. The number of columns should depend on the value of a radio-field of the same field-group without "Automatic Display". I can not get this running.

The problem is that I do not get the value of this radio field into the field-layout. I think this is because I do not get the item-id of the current article via $this->item or $displayData['item']. It is no problem to get the 'number-of-columns' value in other overrides like the fields-layout com_fields/layouts/fields/render.php or the often used blog_item.php etc., but I want to do this just in the alternative layout if possible.

The following render.php is a simpler version of my code without stuff like links or images and without all the different versions I tried to get the field-value of 'number-of-columns' to $numberOfColumns. Just kept the variable where it should be echoed.

I was looking into almost every question about "custom fields" on stackexchange and other sites. Did try the helpers and different answers to fetch the item-id and field-values but without any luck.

render.php

<?php
defined('_JEXEC') or die;

if (!key_exists('field', $displayData))
{
    return;
}

$field = $displayData['field'];
$value = $field->value;


if ($value == '')
{
    return;
}

?>

<div class="cols-<?php echo $numberOfColumns; ?>">    
    <?php   
        $obj = json_decode($value, true);
        foreach ($obj as $value) : 

            $headline = $value['Headline'];
            $text= $value['Text'];
    ?>     
        <div class="item">
            <h3><?php echo $headline; ?></h3>
            <div class="content-wrapper">
                <p><?php echo $text; ?></p>
            </div>
        </div>
        <?php endforeach; ?>
</div>

repeatable.php

defined('_JEXEC') or die;

$fieldValue = $field->value;

if ($fieldValue === '')
{
    return;
}

// Get the values
$fieldValues = json_decode($fieldValue, true);

if (empty($fieldValues))
{
    return;
}

echo $fieldValue;

Answer 1

Create an override of com_fields/layouts/fields/render.php. Find this line:

$content = FieldsHelper::render($context, 'field.' . $layout, array('field' => $field));

Change it to also pass the item to field layout:

$content = FieldsHelper::render($context, 'field.' . $layout, array('field' => $field, 'item' => $item));

The item with its fields is now accessible in com_fields/layouts/field/render.php.

Answer 2

Here's a backstop solution, for using if no-one comes up with a better idea.

The basic approach is to use a plugin which is triggered by onContentPrepare. In this plugin it gets and processes the custom fields to find the number-of-columns field. It finds the value of this field and stores it in a PHP global variable, which then can be accessed in the render function.

I developed the plugin in a folder plg_content_setcolumns, and here are the files:

setcolumns.xml

<?xml version="1.0" encoding="utf-8"?>
<extension version="3.8" type="plugin" group="content" method="upgrade">
    <name>Set number of columns</name>
    <description>Plugin to set number of columns from a custom field</description>
    <files>
        <filename plugin="setcolumns">setcolumns.php</filename>
    </files>
</extension>

setcolumns.php

<?php
defined( '_JEXEC' ) or die;

class plgContentSetColumns extends JPlugin
{
     public function onContentPrepare($context, $item, $params, $offset)
     {
         if ($context == "com_content.article") 
        {
            JLoader::register('FieldsHelper', JPATH_ADMINISTRATOR . '/components/com_fields/helpers/fields.php');
            $fields = FieldsHelper::getFields('com_content.article', $item);
            global $ncols;
            $ncols = false;
            foreach ($fields as $field)
            {
                if ($field->name == 'number-of-columns')
                {
                    $ncols = $field->value;
                    break;
                }
            }
        }
        return true;
    }
}

You can then access $GLOBALS['ncols'] in your render code.

You may have to change some variables to suit your own field names.