Answers:
检查以下示例，使用objectManager使用父类别ID获取特定父类别的所有子类别的列表。
<?php
$objectManager = \Magento\Framework\App\ObjectManager::getInstance();
$catId = 2; //Parent Category ID
$subCategory = $objectManager->create('Magento\Catalog\Model\Category')->load($catId);
$subCats = $subCategory->getChildrenCategories();
$_helper = $this->helper('Magento\Catalog\Helper\Output');
?>
<ul class="sub-cat-ul">
<?php
foreach ($subCats as $subcat) {
$_category = $objectManager->create('Magento\Catalog\Model\Category')->load($subcat->getId());
$subcaturl = $subcat->getUrl();
$_imgHtml = '';
if ($_imgUrl = $_category->getImageUrl()) {
$_imgHtml = '<img src="' . $_imgUrl . '" />';
$_imgHtml = $_helper->categoryAttribute($_category, $_imgHtml, 'image');
} ?>
<li class="cat-li">
<div class="cat-image">
<a href="<?php echo $subcaturl ?>"><?php echo $_imgHtml;?></a>
</div>
<div class="info">
<h4><?php echo $subcat->getName(); ?></h4>
<a class="link" href="<?php echo $subcaturl ?>"><?php /* @escapeNotVerified */ echo __('View more') ?></a>
</div>
</li>
<?php } ?>
</ul>=====
检查以下示例，以使用存储库使用父类别ID列出特定父类别的所有子类别。
首先在构造中添加CategoryRepository：
<?php
protected $categoryRepository;
public function __construct(
\Magento\Catalog\Model\CategoryRepository $categoryRepository
) {
$this->categoryRepository = $categoryRepository;
}
?>现在，您可以使用以下方式：
<?php
$categoryId = [YOUR_CATEGORY_ID];
$category = $this->categoryRepository->get($categoryId);
$subCategories = $category->getChildrenCategories();
foreach($subCategories as $subCategory) {
echo $subCategory->getName();
/* For Sub Categories */
if($subcategorie->hasChildren()) {
$childCategoryObj = $this->categoryRepository->get($subCategory->getId());
$childSubcategories = $childCategoryObj->getChildrenCategories();
foreach($childSubcategories as $childSubcategory) {
echo $childSubcategory->getName();
}
}
}
?>您需要在类中添加一个依赖项\Magento\Catalog\Model\ResourceModel\Category\CollectionFactory。
像这样：
protected $categoryCollectionFactory;
public function __construct(
...
\Magento\Catalog\Model\ResourceModel\Category\CollectionFactory $categoryCollectionFactory,
...
) {
...
$this->categoryCollectionFactory = $categoryCollectionFactory;
...
}
public function getDescendants($category, $levels = 2)
{
if ((int)$levels < 1) {
$levels = 1;
}
$collection = $this->categoryCollectionFactory->create()
->addPathsFilter($category->getPath().'/')
->addLevelFilter($category->getLevel() + $levels);
return $collection;
}现在，您只需要getDescendants使用$category对象作为参数以及子类别所需的级别数（在本例中为2）调用该方法。
$block->getDescendents($category, 2)where $category是主要类别。（我不知道你从哪里得到的）。
始终尝试使用存储库。这是一个例子。
CategoryRepository通过构造注入
protected $categoryRepository;
public function __construct(
\Magento\Catalog\Model\CategoryRepository $categoryRepository
) {
$this->categoryRepository = $categoryRepository;
}现在，您可以使用以下方式：
$parent_category_id = 3;
$categoryObj = $this->categoryRepository->get($parent_category_id);
$subcategories = $categoryObj->getChildrenCategories();
foreach($subcategories as $subcategorie) {
echo ' --> '.$subcategorie->getName().'<br/>';
}对于2级子类别：
$categoryObj = $this->categoryRepository->get($parent_category_id);
$subcategories = $categoryObj->getChildrenCategories();
foreach($subcategories as $subcategorie) {
echo ' --> '.$subcategorie->getName().'<br/>';
if($subcategorie->hasChildren()) {
$childCategoryObj = $this->categoryRepository->get($subcategorie->getId());
$childSubcategories = $childCategoryObj->getChildrenCategories();
foreach($childSubcategories as $childSubcategorie) {
echo ' --> '.$childSubcategorie->getName().'<br/>';
}
}
}\Magento\Catalog\Api\CategoryRepositoryInterface
$objectManager = \Magento\Framework\App\ObjectManager::getInstance();
$category = $objectManager->get('Magento\Framework\Registry')->registry('current_category');//get current category
$catId = $category->getId(); // Parent Category ID
$subcategory = $objectManager->create('Magento\Catalog\Model\Category')->load($catId);
$subcats = $subcategory->getChildrenCategories();
$categoryHelper = $this->getCategoryHelper();
<div class="category_bg mobile">
<ul id="main_cat_bg" class="main_cat_bg">
<?php
$cat_togg = 0;
foreach ($subcats as $subcat) {
if (!$subcat->getIsActive()) {
continue;
}
$_category = $objectManager->create('Magento\Catalog\Model\Category')->load($subcat->getId());
//$_outputhelper = $this->helper('Magento\Catalog\Helper\Output');
$helper = $this->helper('SR\CategoryImage\Helper\Category');
$subcaturl = $subcat->getUrl();
$imageUrlthum = $helper->getImageUrl($_category->getData('thumbnail'));
//$imageUrlthum = resize($_category->getData('thumbnail'),153,153);
//$cat_desc = $_category->getCatDescription();
$_imgHtml = '';
if ($imageUrlthum) {
$_imgHtml = '<img src="' . $imageUrlthum. '" />';
//$_imgHtml = $_outputhelper->categoryAttribute($_category, $_imgHtml, 'image');
/* @escapeNotVerified */
}
?>
<li>
<div class="sub_cat_content_main">
<div class="cat_image_text">
<a href="<?php echo $subcaturl ?>">
<?php echo $_imgHtml;?>
<!--<div class="desicription_part">-->
<?php //echo $cat_desc; ?>
<!--</div>-->
</a>
<div class="sub_name_bg">
<a href="<?php echo $subcaturl ?>">
<?php echo $subcat->getName(); ?>
</a>
</div>
<!-- Start 3rd Level Chiled Category-->
<?php
$objectManager = \Magento\Framework\App\ObjectManager::getInstance();
$object_managertwo = $objectManager->create('Magento\Catalog\Model\Category')->load($subcat->getId());
$subcatslevelthird = $object_managertwo->getChildrenCategories();
?>
<?php if ($subcatslevelthird->count() > 0) { ?>
<ul class="sub_cat_bg">
<?php
foreach ($subcatslevelthird as $subcatthird) {
$_outputhelper = $this->helper('Magento\Catalog\Helper\Output');
$subcaturl = $subcatthird->getUrl();
?>
<li class="cat_image_bg">
<a class="level-top" href="<?php //echo $subcaturl ?>">
<span><?php //echo $subcatthird->getName(); ?></span>
</a>
<div class="child_name_bg">
<span><?php echo $subcatthird->getName(); ?></span>
</div>
<!-- Start 4th Level Chiled Category-->
<?php
$_objectManager = \Magento\Framework\App\ObjectManager::getInstance();
$object_managerthree = $_objectManager->create('Magento\Catalog\Model\Category')->load($subcatthird->getId());
$subcatslevel = $object_managerthree->getChildrenCategories();
?>
<?php if ($subcatslevel->count() > 0){?>
<ul class="chiled_cat_bg">
<?php
foreach ($subcatslevel as $subcatlevel) {
$_outputhelper = $this->helper('Magento\Catalog\Helper\Output');
$subcaturl = $subcatlevel->getUrl();
?>
<li class="cat_image_bg">
<a class="level-top" href="<?php echo $subcaturl ?>">
<span><?php echo $subcatlevel->getName(); ?></span>
</a>
</li>
<?php } ?>
</ul>
<?php } ?>
<!-- End 4th level Chiled Category-->
</li>
<?php } ?>
</ul>
<?php } ?>
<!-- End 3rd level Chiled Category-->
</div>
</div>
</li>
<?php } ?>
</ul>
<div id="view_more">
View more
</div>
</div>使用下面的代码来获取特定类别的所有活动子类别。
函数getChildCategories（$ categoryId）给出所有子类别。其中$ categoryId-是父类别ID
<?php
namespace YourModuleName\CategoryLink\Block;
use Magento\Framework\View\Element\Template;
use Magento\Framework\View\Element\Template\Context;
use Magento\Catalog\Model\CategoryFactory;
/**
* Category link block
*/
class Link extends Template
{
/**
* @var Magento\Catalog\Model\CategoryFactory
*/
protected $_categoryFactory;
/**
*
* @param Context $context
* @param array $data
*/
public function __construct(
Context $context,
CategoryFactory $categoryFactory,
array $data = []
) {
parent::__construct($context, $data);
$this->_categoryFactory = $categoryFactory;
}
/**
* Get children categories
*
* @param $categoryId Parent category id
* @return Magento\Catalog\Model\ResourceModel\Category\Collection
*/
public function getChildCategories($categoryId)
{
$_category = $this->_categoryFactory->create();
$category = $_category->load($categoryId);
//Get category collection
$collection = $category->getCollection()
->addIsActiveFilter()
->addOrderField('name')
->addIdFilter($category->getChildren());
return $collection;
}
} $ category-> getChildren（）-这将提供所有分类类别的ID。
$subcats = $subcategory->getChildrenCategories();