Symfony3.3+Sonata：如何为sonata_type_model启用自定义排序？

嘿，我之前在Sonata Admin里处理多对多关联的自定义排序时也踩过一模一样的坑！原生的多对多关联因为没有存储排序信息的字段，根本没法支持用户自定义调整顺序，更别说删除中间项后排序混乱的问题了。咱们可以通过把多对多拆成一对多+多对一的中间实体结构来解决，具体步骤如下：

1. 创建中间实体存储排序字段 #

首先需要新建一个中间实体（比如QuestionGalleryItem），用来关联Question和QuestionGallery，同时添加position字段保存排序位置：

// src/AppBundle/Entity/QuestionGalleryItem.php
namespace AppBundle\Entity;

use Doctrine\ORM\Mapping as ORM;

/**
 * @ORM\Entity
 * @ORM\Table(name="question_gallery_item")
 */
class QuestionGalleryItem
{
    /**
     * @ORM\Id
     * @ORM\GeneratedValue(strategy="AUTO")
     * @ORM\Column(type="integer")
     */
    private $id;

    /**
     * @ORM\ManyToOne(targetEntity="QuestionGallery", inversedBy="galleryItems")
     * @ORM\JoinColumn(nullable=false)
     */
    private $gallery;

    /**
     * @ORM\ManyToOne(targetEntity="Question", inversedBy="galleryItems")
     * @ORM\JoinColumn(nullable=false)
     */
    private $question;

    /**
     * @ORM\Column(type="integer")
     */
    private $position = 0;

    // 生成对应的getter和setter方法
    public function getId() { return $this->id; }
    public function setGallery(QuestionGallery $gallery) { $this->gallery = $gallery; return $this; }
    public function getGallery() { return $this->gallery; }
    public function setQuestion(Question $question) { $this->question = $question; return $this; }
    public function getQuestion() { return $this->question; }
    public function setPosition(int $position) { $this->position = $position; return $this; }
    public function getPosition() { return $this->position; }
}

2. 修改原有实体的关联关系 #

把QuestionGallery和Question的多对多关联改成一对多关联到中间实体：

修改QuestionGallery实体 #

// src/AppBundle/Entity/QuestionGallery.php
namespace AppBundle\Entity;

use Doctrine\Common\Collections\ArrayCollection;
use Doctrine\ORM\Mapping as ORM;

/**
 * @ORM\Entity
 */
class QuestionGallery
{
    // ... 原有字段和方法

    /**
     * @ORM\OneToMany(targetEntity="QuestionGalleryItem", mappedBy="gallery", cascade={"persist", "remove"}, orphanRemoval=true)
     * @ORM\OrderBy({"position" = "ASC"})
     */
    private $galleryItems;

    public function __construct()
    {
        $this->galleryItems = new ArrayCollection();
    }

    public function addGalleryItem(QuestionGalleryItem $item)
    {
        $item->setGallery($this);
        if (!$this->galleryItems->contains($item)) {
            $this->galleryItems->add($item);
        }
        return $this;
    }

    public function removeGalleryItem(QuestionGalleryItem $item)
    {
        $this->galleryItems->removeElement($item);
        return $this;
    }

    public function getGalleryItems()
    {
        return $this->galleryItems;
    }
}

修改Question实体（类似操作） #

// src/AppBundle/Entity/Question.php
namespace AppBundle\Entity;

use Doctrine\Common\Collections\ArrayCollection;
use Doctrine\ORM\Mapping as ORM;

/**
 * @ORM\Entity
 */
class Question
{
    // ... 原有字段和方法

    /**
     * @ORM\OneToMany(targetEntity="QuestionGalleryItem", mappedBy="question", cascade={"persist", "remove"})
     */
    private $galleryItems;

    public function __construct()
    {
        $this->galleryItems = new ArrayCollection();
    }

    // 对应的add/remove/getGalleryItems方法
}

3. 配置Sonata Admin的表单字段 #

在QuestionGalleryAdmin里，用sonata_type_collection替代原来的sonata_type_model，并开启排序支持：

// src/AppBundle/Admin/QuestionGalleryAdmin.php
namespace AppBundle\Admin;

use Sonata\AdminBundle\Admin\AbstractAdmin;
use Sonata\AdminBundle\Form\FormMapper;
use Sonata\AdminBundle\Form\Type\CollectionType;

class QuestionGalleryAdmin extends AbstractAdmin
{
    protected function configureFormFields(FormMapper $formMapper)
    {
        $formMapper
            // ... 其他表单字段
            ->add('galleryItems', CollectionType::class, [
                'label' => 'Gallery Questions',
                'by_reference' => false,
                'allow_add' => true,
                'allow_delete' => true,
                'sortable' => true,
                'sortable_field' => 'position',
                'required' => false,
            ], [
                'edit' => 'inline',
                'inline' => 'table', // 用表格形式展示，方便拖拽排序
                'sortable' => 'position',
            ])
        ;
    }

    // 自动重新排序position字段，解决删除中间项后的排序混乱
    public function preUpdate($object)
    {
        $this->reorderPositions($object->getGalleryItems());
        parent::preUpdate($object);
    }

    public function prePersist($object)
    {
        $this->reorderPositions($object->getGalleryItems());
        parent::prePersist($object);
    }

    private function reorderPositions($items)
    {
        $position = 0;
        foreach ($items as $item) {
            $item->setPosition($position++);
        }
    }
}

4. 最后一步：更新数据库 #

执行Doctrine的迁移命令来创建中间表：

php bin/console doctrine:schema:update --force

这样设置后，用户就能在Sonata Admin的表单里拖拽调整Question的顺序，删除中间项后，剩余项的position也会自动重新排序，完全解决你遇到的问题！

内容的提问来源于stack exchange，提问作者Mayor of the Plattenbaus