Provide views handler (filters) for the fields

Filters seem to be generally available through the field schema already!

For example after adding the availability field on a commerce product variation, you can add a filter for "orderable".

But the type is string, so maybe we need to alter the information to be boolean for views: https://git.drupalcode.org/project/drupal/-/blob/11.x/core/modules/views...

On the other hand, I wonder why views isn't able to detect that based on the Schema, so this may need further investigations before, so we don't hack something that just needs to be resolved in core.

Here's what ChatGPT says about using a checkbox for the "Orderable" option (unclear if this is correct!):

To display a custom field type as a boolean checkbox in a Drupal 10 Views filter, you can create a custom Views filter plugin. Here’s a step-by-step guide:

1. **Create the Custom Filter Plugin**:
- Define a new filter plugin by extending the `FilterPluginBase` class.
- Implement the `valueForm` method to define the checkbox options.
- Implement the `query` method to handle the filtering logic.

2. **Example Code**:
- Create a file named `BooleanFilter.php` in your custom module's `src/Plugin/views/filter` directory.

```php
namespace Drupal\your_module\Plugin\views\filter;

use Drupal\Core\Form\FormStateInterface;
use Drupal\views\Plugin\views\filter\FilterPluginBase;

/**
* Defines a filter for boolean fields.
*
* @ViewsFilter("boolean_filter")
*/
class BooleanFilter extends FilterPluginBase {

/**
* {@inheritdoc}
*/
protected function valueForm(&$form, FormStateInterface $form_state) {
$form['value'] = [
'#type' => 'checkbox',
'#title' => $this->t('Boolean Filter'),
'#default_value' => $this->value,
];
}

/**
* {@inheritdoc}
*/
public function query() {
$this->ensureMyTable();
$value = $this->value ? 1 : 0;
$this->query->addWhere($this->options['group'], "{$this->tableAlias}.{$this->realField}", $value);
}
}
```

3. **Register the Plugin**:
- Implement `hook_views_data()` in your module to register the custom filter.

```php
/**
* Implements hook_views_data().
*/
function your_module_views_data() {
$data = [];
$data['your_table']['boolean_filter'] = [
'title' => t('Boolean Filter'),
'filter' => [
'title' => t('Boolean Filter'),
'help' => t('Filter by boolean value.'),
'id' => 'boolean_filter',
],
];
return $data;
}
```

4. **Use the Filter in Views**:
- Add the custom filter to your view and expose it to users.

```php
$view = \Drupal\views\Views::getView('your_view');
$view->display_handler->setOption('filters', [
'boolean_filter' => [
'id' => 'boolean_filter',
'table' => 'your_table',
'field' => 'your_field',
'exposed' => TRUE,
],
]);
```

This setup will allow you to use a checkbox for your custom field type in the Views filter, providing a more user-friendly interface¹².

If you have any specific questions or run into issues, feel free to ask!

Quelle: Unterhaltung mit Copilot, 10.10.2024
(1) [SOLVED] Creating filter for 2 boolean fields | Drupal.org. https://www.drupal.org/forum/support/module-development-and-code-questio... → .
(2) Define a Custom Views Filter Plugin for Drupal 8, 9, and 10 - Drupalize.Me. https://drupalize.me/tutorial/define-custom-views-filter-plugin.
(3) Drupal 10 Views: How To Setup Faceted Search - Xandermar LLC. https://www.xandermar.com/articles/drupal-10-views-how-setup-faceted-search.
(4) class views_handler_filter_boolean_operator | Drupal API. https://api.drupal.org/api/views/handlers%21views_handler_filter_boolean....
(5) Conditional Form Fields | Form API | Drupal Wiki guide on Drupal.org. https://www.drupal.org/docs/drupal-apis/form-api/conditional-form-fields → .

For the select filter (availability status):

To display a custom field type as a boolean checkbox in a Drupal 10 Views filter, you can create a custom Views filter plugin. Here’s a step-by-step guide:

1. **Create the Custom Filter Plugin**:
- Define a new filter plugin by extending the `FilterPluginBase` class.
- Implement the `valueForm` method to define the checkbox options.
- Implement the `query` method to handle the filtering logic.

2. **Example Code**:
- Create a file named `BooleanFilter.php` in your custom module's `src/Plugin/views/filter` directory.

```php
namespace Drupal\your_module\Plugin\views\filter;

use Drupal\Core\Form\FormStateInterface;
use Drupal\views\Plugin\views\filter\FilterPluginBase;

/**
* Defines a filter for boolean fields.
*
* @ViewsFilter("boolean_filter")
*/
class BooleanFilter extends FilterPluginBase {

/**
* {@inheritdoc}
*/
protected function valueForm(&$form, FormStateInterface $form_state) {
$form['value'] = [
'#type' => 'checkbox',
'#title' => $this->t('Boolean Filter'),
'#default_value' => $this->value,
];
}

/**
* {@inheritdoc}
*/
public function query() {
$this->ensureMyTable();
$value = $this->value ? 1 : 0;
$this->query->addWhere($this->options['group'], "{$this->tableAlias}.{$this->realField}", $value);
}
}
```

3. **Register the Plugin**:
- Implement `hook_views_data()` in your module to register the custom filter.

```php
/**
* Implements hook_views_data().
*/
function your_module_views_data() {
$data = [];
$data['your_table']['boolean_filter'] = [
'title' => t('Boolean Filter'),
'filter' => [
'title' => t('Boolean Filter'),
'help' => t('Filter by boolean value.'),
'id' => 'boolean_filter',
],
];
return $data;
}
```

4. **Use the Filter in Views**:
- Add the custom filter to your view and expose it to users.

```php
$view = \Drupal\views\Views::getView('your_view');
$view->display_handler->setOption('filters', [
'boolean_filter' => [
'id' => 'boolean_filter',
'table' => 'your_table',
'field' => 'your_field',
'exposed' => TRUE,
],
]);
```

This setup will allow you to use a checkbox for your custom field type in the Views filter, providing a more user-friendly interface¹².

If you have any specific questions or run into issues, feel free to ask!

Quelle: Unterhaltung mit Copilot, 10.10.2024
(1) [SOLVED] Creating filter for 2 boolean fields | Drupal.org. https://www.drupal.org/forum/support/module-development-and-code-questio... → .
(2) Define a Custom Views Filter Plugin for Drupal 8, 9, and 10 - Drupalize.Me. https://drupalize.me/tutorial/define-custom-views-filter-plugin.
(3) Drupal 10 Views: How To Setup Faceted Search - Xandermar LLC. https://www.xandermar.com/articles/drupal-10-views-how-setup-faceted-search.
(4) class views_handler_filter_boolean_operator | Drupal API. https://api.drupal.org/api/views/handlers%21views_handler_filter_boolean....
(5) Conditional Form Fields | Form API | Drupal Wiki guide on Drupal.org. https://www.drupal.org/docs/drupal-apis/form-api/conditional-form-fields → .

Setting priority to normal as this would be helpful to find product variations with certain availability status.

Put it on my list.