Question

我从buildForm函数创建了一个自定义表单。在这种形式中，我想添加一个图像字段。

我可以通过以下代码执行此操作：

$form['main']['image'] = array(
    '#type' => 'text_format',
    '#title' => t('image'),
    '#default_value' => array(10),
);

我可以上传和删除表单中的图片。但是，当我上传图片时，我没有预览。我的意思是，当我通过Drupal UI创建内容时。我可以添加一个预配置的“图像”字段。当我通过此“图像”字段上传图像时，我会预览图像。

在这里，当我以编程方式创建field元素时，我上传她时没有预览图像。当我通过“图像”字段上传她时，如何使用api Drupal进行图像预览？

Answer 1

所以这是我如何让表单显示缩略图。我基本上做的是获取ImageWidget :: process中的代码，将其放在主题预处理器中，并将元素的#theme属性设置为image_widget。

表单类中的图像元素应如下所示：

$form['profile_image'] = [
   '#type' => 'managed_file',
   '#title' => t('Profile Picture'),
   '#upload_validators' => array(
       'file_validate_extensions' => array('gif png jpg jpeg'),
       'file_validate_size' => array(25600000),
   ),
   **'#theme' => 'image_widget',**
   **'#preview_image_style' => 'medium',**
   '#upload_location' => 'public://profile-pictures',
   '#required' => TRUE,
];

在name_of_default_theme.theme文件中，您需要以下内容：

function name_of_default_theme_preprocess_image_widget(&$variables) {
    $element = $variables['element'];

    $variables['attributes'] = array('class' => array('image-widget', 'js-form-managed-file', 'form-managed-file', 'clearfix'));

    if (!empty($element['fids']['#value'])) {
        $file = reset($element['#files']);
        $element['file_' . $file->id()]['filename']['#suffix'] = ' <span class="file-size">(' . format_size($file->getSize()) . ')</span> ';
        $file_variables = array(
            'style_name' => $element['#preview_image_style'],
            'uri' => $file->getFileUri(),
        );

        // Determine image dimensions.
        if (isset($element['#value']['width']) && isset($element['#value']['height'])) {
            $file_variables['width'] = $element['#value']['width'];
            $file_variables['height'] = $element['#value']['height'];
        } else {
            $image = \Drupal::service('image.factory')->get($file->getFileUri());
            if ($image->isValid()) {
                $file_variables['width'] = $image->getWidth();
                $file_variables['height'] = $image->getHeight();
            }
            else {
                $file_variables['width'] = $file_variables['height'] = NULL;
            }
        }

        $element['preview'] = array(
            '#weight' => -10,
            '#theme' => 'image_style',
            '#width' => $file_variables['width'],
            '#height' => $file_variables['height'],
            '#style_name' => $file_variables['style_name'],
            '#uri' => $file_variables['uri'],
        );

        // Store the dimensions in the form so the file doesn't have to be
        // accessed again. This is important for remote files.
        $element['width'] = array(
            '#type' => 'hidden',
            '#value' => $file_variables['width'],
        );
        $element['height'] = array(
            '#type' => 'hidden',
            '#value' => $file_variables['height'],
        );
    }

    $variables['data'] = array();
    foreach (Element::children($element) as $child) {
        $variables['data'][$child] = $element[$child];
    }
}

解决方案效果很好，但图像模块缺少带有@FormElement注释的类。这就是元素没有正确呈现的原因。

Answer 2

您可以尝试使用managed_file类型吗？

'#type' => 'managed_file'

Answer 3

很好的回答，我唯一要做的更改是使用令牌作为上载位置，使用字节作为文件上载大小，尽管我猜这取决于用例。类似于以下内容（为了简单起见，将大部分代码删除了。

namespace Drupal\my_module\Form;

use Drupal\Core\Form\FormBase;
use Drupal\Core\Form\FormStateInterface;
use Symfony\Component\DependencyInjection\ContainerInterface;
use Drupal\Core\Session\AccountProxyInterface;
use Drupal\Component\Utility\Bytes;
use Drupal\Core\Utility\Token;

class SampleForm extends FormBase
{

  protected $currentUser;

  protected $token;


  public function __construct(AccountProxyInterface $current_user, Token $token) {
    $this->currentUser = $current_user;
    $this->token = $token;
  }


  public static function create(ContainerInterface $container)
  {
    return new static(
      $container->get('current_user'),
      $container->get('token')
    );
  }


  /**
   * {@inheritdoc}
   */
  public function buildForm(array $form, FormStateInterface $form_state) {

    $form['sample_image'] = [
        '#type' => 'managed_file',
        '#title' => t('Profile Picture'),
        '#upload_validators' => array(
          'file_validate_extensions' => array('gif png jpg jpeg'),
          'file_validate_size' => file_upload_max_size() / pow(Bytes::KILOBYTE, 2) . 'M',
        ),
      '#theme' => 'image_widget',
      '#preview_image_style' => 'medium',
      '#upload_location' => $this->token->replace('private://[date:custom:Y]-[date:custom:m]'),
      '#required' => TRUE,
    ];

    return $form;
  }
}

Answer 4

将其主题化以处理多个文件上传。来自上面@Je Suis Alrick 的回答。

    function themename_preprocess_image_widget(&$variables) {
    $element = $variables['element'];

    $variables['attributes'] = array('class' => array('image-widget', 'js-form-managed-file', 'form-managed-file', 'clearfix'));
   
    if (!empty($element['fids']['#value'])) {

        foreach ($element['#files'] as $file) {
         
            $element['file_' . $file->id()]['filename']['#suffix'] = ' <span class="file-size">(' . format_size($file->getSize()) . ')</span> ';
            $file_variables = array(
                'style_name' => $element['#preview_image_style'],
                'uri' => $file->getFileUri(),
            );

            // Determine image dimensions.
            if (isset($element['#value']['width']) && isset($element['#value']['height'])) {
                $file_variables['width'] = $element['#value']['width'];
                $file_variables['height'] = $element['#value']['height'];
            } else {
                $image = \Drupal::service('image.factory')->get($file->getFileUri());
                if ($image->isValid()) {
                    $file_variables['width'] = $image->getWidth();
                    $file_variables['height'] = $image->getHeight();
                }
                else {
                    $file_variables['width'] = $file_variables['height'] = NULL;
                }
            }

            $element['preview'][] = array(
                '#weight' => -10,
                '#theme' => 'image_style',
                '#width' => $file_variables['width'],
                '#height' => $file_variables['height'],
                '#style_name' => $file_variables['style_name'],
                '#uri' => $file_variables['uri'],
            );

            // Store the dimensions in the form so the file doesn't have to be
            // accessed again. This is important for remote files.
            $element['width'] = array(
                '#type' => 'hidden',
                '#value' => $file_variables['width'],
            );
            $element['height'] = array(
                '#type' => 'hidden',
                '#value' => $file_variables['height'],
            );
        }
    }


    $variables['data'] = array();
    foreach (\Drupal\Core\Render\Element::children($element) as $child) {
        $variables['data'][$child] = $element[$child];
    }
}

Drupal 8，使用预览

4 个答案: