在Drupal8中如何在字段设置表单中添加复选框

在Drupal 8中，要在字段设置表单中添加复选框，可以按照以下步骤进行操作：

创建一个自定义模块（如果已经有自定义模块可以直接使用）。
在模块的根目录下创建一个新的文件夹，命名为"src/Form"。
在"src/Form"文件夹中创建一个新的文件，命名为"CustomFieldSettingsForm.php"。
在"CustomFieldSettingsForm.php"文件中编写以下代码：

<?php

namespace Drupal\your_module\Form;

use Drupal\Core\Field\FieldDefinitionInterface;
use Drupal\Core\Field\FieldStorageDefinitionInterface;
use Drupal\Core\Form\FormStateInterface;
use Drupal\Core\StringTranslation\TranslatableMarkup;
use Drupal\field_ui\FieldUI;
use Drupal\field_ui\Form\FieldStorageConfigEditForm;

/**
 * Implements the custom field settings form.
 */
class CustomFieldSettingsForm extends FieldStorageConfigEditForm {

  /**
   * {@inheritdoc}
   */
  public function form(array $form, FormStateInterface $form_state) {
    $form = parent::form($form, $form_state);

    // Get the field definition.
    $field_definition = $form_state->get('field_definition');
    if (!$field_definition instanceof FieldDefinitionInterface) {
      return $form;
    }

    // Add a checkbox element to the form.
    $form['custom_checkbox'] = [
      '#type' => 'checkbox',
      '#title' => $this->t('Custom Checkbox'),
      '#default_value' => $field_definition->getSetting('custom_checkbox'),
      '#description' => $this->t('Enable this checkbox to enable custom functionality.'),
    ];

    return $form;
  }

  /**
   * {@inheritdoc}
   */
  public function submitForm(array &$form, FormStateInterface $form_state) {
    parent::submitForm($form, $form_state);

    // Get the field definition.
    $field_definition = $form_state->get('field_definition');
    if (!$field_definition instanceof FieldDefinitionInterface) {
      return;
    }

    // Save the checkbox value to the field settings.
    $field_definition->setSetting('custom_checkbox', $form_state->getValue('custom_checkbox'));
  }

}

在模块的根目录下创建一个新的文件，命名为"your_module.module"（替换"your_module"为你的模块名称）。
在"your_module.module"文件中添加以下代码：

<?php

use Drupal\Core\Field\FieldDefinitionInterface;
use Drupal\Core\Field\FieldStorageDefinitionInterface;
use Drupal\Core\Form\FormStateInterface;
use Drupal\Core\StringTranslation\TranslatableMarkup;
use Drupal\field_ui\FieldUI;
use Drupal\field_ui\Form\FieldStorageConfigEditForm;

/**
 * Implements hook_form_alter().
 */
function your_module_form_alter(&$form, FormStateInterface $form_state, $form_id) {
  // Check if the form is the field settings form.
  if (strpos($form_id, 'field_ui_field_config_edit_form') !== FALSE) {
    // Get the field definition.
    $field_definition = $form_state->get('field_definition');
    if (!$field_definition instanceof FieldDefinitionInterface) {
      return;
    }

    // Check if the field type is supported.
    if ($field_definition->getType() == 'your_field_type') {
      // Add a custom submit handler to save the field settings.
      $form['actions']['submit']['#submit'][] = 'your_module_field_settings_submit';
    }
  }
}

/**
 * Custom submit handler for the field settings form.
 */
function your_module_field_settings_submit(array &$form, FormStateInterface $form_state) {
  // Get the field definition.
  $field_definition = $form_state->get('field_definition');
  if (!$field_definition instanceof FieldDefinitionInterface) {
    return;
  }

  // Save the checkbox value to the field settings.
  $field_definition->setSetting('custom_checkbox', $form_state->getValue('custom_checkbox'));
}

在模块的根目录下创建一个新的文件，命名为"your_module.info.yml"（替换"your_module"为你的模块名称）。
在"your_module.info.yml"文件中添加以下代码：

name: 'Your Module'
type: module
description: 'Custom module for Drupal 8.'
package: Custom
core_version_requirement: ^8 || ^9
dependencies:
  - field_ui:field_ui