ResultSummary.php

<?php

namespace Drupal\gojara_activity_results\Plugin\views\field;

use Drupal\Component\Serialization\Json;
use Drupal\Core\Link;
use Drupal\Core\Url;
use Drupal\views\Plugin\views\field\FieldPluginBase;
use Drupal\views\ResultRow;

/**
 * Provides Result Summary field handler.
 *
 * @ViewsField("activity_result_summary")
 */
class ResultSummary extends FieldPluginBase {


  /**
   * {@inheritdoc}
   */
  public function query() {
  }

  /**
   * {@inheritdoc}
   */
  public function render(ResultRow $values) {
    /** @var \Drupal\gojara_activity_results\ActivityResultInterface $result */
    $result = $values->_entity;

    $data = json_decode($result->get('field_data')->value);

    $result_summary = 'Verb: ' . $data->verb->display->{"en-US"} . '<br />';
    if (isset($data->result)) {
      if (isset($data->result->completion)) {
        $result_summary .= 'Result completion: ' . ($data->result->completion ? 'true' : 'false') . '<br />';
      }

      if (isset($data->result->success)) {
        $result_summary .= 'Result success: ' . ($data->result->success ? 'true' : 'false') . '<br />';
      }
    }
    else {
      $result_summary .= 'Result: - <br />';
    }

    $output['summary'] = [
      '#markup' => $result_summary,
    ];

    $link_url = Url::fromRoute('gojara_activity_results.result_json', [
      'activity_result' => $result->id(),
    ]);
    $link_url->setOptions([
      'attributes' => [
        'class' => [
          'use-ajax',
        ],
        'data-dialog-type' => 'modal',
      ]
    ]);

    $output['json_link'] = Link::fromTextAndUrl(t('Raw JSON'), $link_url)->toRenderable();
    $output['#attached'] = ['library' => ['core/drupal.dialog.ajax']];

    return $output;
  }

}