How to get the attribute values for multiselect in magento 2

Question

I want to post this magento 1 code for magento 2

$attributeId = Mage::getResourceModel('eav/entity_attribute')->getIdByCode('catalog_product','makemulti');
     $attribute = Mage::getModel('catalog/resource_eav_attribute')->load($attributeId);
     $attributeOptions = $attribute ->getSource()->getAllOptions();

---

This is my controller file, I have created attribute as v_models, I put the code that you have given but values are not loaded in drop down.

  <?php
    namespace Kamtech\Ymmems\Controller\Ymmemssearch;
    class Model extends \Magento\Framework\App\Action\Action
    {
     public function execute()
        {


        $obj = \Magento\Framework\App\ObjectManager::getInstance();
        $attributesList = $obj->create('Magento\Catalog\Model\Entity\Attribute')->loadByCode('catalog_product', 'v_model');

        foreach ($attributesList->getSource()->getAllOptions() as $optionInfo) {
            echo "List of Multiselect <pre>";print_r($optionInfo);exit;
            if($optionInfo['value'] != ''){
                echo $optionInfo['value'].' = '.$optionInfo['label']."<br>";
            }
        }


        foreach($this->getRequest()->getParams() as $make=>$value) {
                //echo '<dt><strong>Param: </strong>'.$make.'</dt>';
                //echo '<dt><strong>Value: </strong>'.$value.'</dt>';
            }

            if($value=="-1")
            {
            echo '<dt><strong>Param value: </strong>'.$value.'</dt>';
            echo '<select name="model"><option id=-1 value="Select Model">Select Model</option></select>';
             return;
            }
           $makeattribute_code="makes";
           $modelattribute_code="v_models";
         $this->_resources = \Magento\Framework\App\ObjectManager::getInstance()
           ->get('Magento\Framework\App\ResourceConnection');
           $connection= $this->_resources->getConnection();
           $table1=$this->_resources->getTableName ( 'eav_attribute' );
           $table2=$this->_resources->getTableName ( 'catalog_product_entity_varchar' );
           $table3=$this->_resources->getTableName ( 'eav_attribute_option_value' );
           $table4=$this->_resources->getTableName ( 'YMME' );

           $makequery = $connection->query("select attribute_id from ".$table1." where attribute_code='".$makeattribute_code."'");
            $row = $makequery->fetch ();
            $make_attributeid=$row['attribute_id'];

           $genquery1 = $connection->query("select attribute_id from ".$table1." where attribute_code='".$modelattribute_code."'");
           $row = $genquery1->fetch ();
           $model_attributeid=$row['attribute_id'];
            //echo '<dt><strong>Model Attribute: </strong>'.$model_attributeid.'</dt>';

           $storevalues1='';
           $queryString="SELECT distinct value from ".$table2." where attribute_id=".$model_attributeid ." and entity_id in (select entity_id from ".$table2." where attribute_id=".$make_attributeid ." and value like '%".$value."%') order by value";

           echo '<dt><strong>Query: </strong>'.$queryString.'</dt>';

           $genquery2 = $connection->query("SELECT distinct value from ".$table2." where attribute_id=".$model_attributeid ." and entity_id in (select entity_id from ".$table2." where attribute_id=".$make_attributeid ." and value like '%".$value."%') order by value");


            while($rowZ = $genquery2->fetch ()){
                // echo '<dt><strong>124 Inside While loop </strong></dt>';
                if($storevalues1 == '')
                {

                }
                else
                {
                    $storevalues1=$storevalues1.',';
                }
                $storevalues1=$storevalues1.$rowZ['value'];

            }

        $make_option_value_query  =  $connection->query("SELECT value FROM ".$table3." where option_id in (".$value.")");
        $make_option_value_row = $make_option_value_query->fetch ();
        $make_option_value = $make_option_value_row['value'];

        if ($storevalues1 != '')
        {
            $genquery3 = $connection->query ("SELECT distinct option_id,value FROM ".$table3." where option_id in (".$storevalues1." )order by value");
            $fname="getResponseToDiv('year?model='+this.options[this.selectedIndex].value+'&makes='+ymme.make.value,'yeardiv',this.options[this.selectedIndex].value)";
            //  echo '<label for="Model">Model</label>';
            echo '<select id=model name=model onChange='.$fname.' ><option id=-1 value="Select Model">Select Model</option>';

           //$attributeId = Mage::getResourceModel('eav/entity_attribute')->getIdByCode('catalog_product','modelmulti');
          // $attributeId = $this->_eavAttribute->getIdByCode('catalog_product', 'v_models');
          // $attribute = Mage::getModel('catalog/resource_eav_attribute')->load($attributeId);

           //echo "<pre>"; print_r($attributeOptions); echo "</pre>";
           //echo '<option value='.'"'.$attributeOptions[$nz]['value'].'"'.' >'.$attributeOptions[$nz]['label'].' </option>';


            while($row = $genquery3->fetch ())
            {
              for($nz=1;$nz<=count($attributeOptions); $nz++)
                  {
                    $row['value']=$row['option_id'];
                    if($row['value']==$attributeOptions[$nz]['value'])
                     {
                        $ymmquery1 = $connection->query ("SELECT distinct model from ".$table4." where model ='".$attributeOptions[$nz]['label']."' and make = '".$make_option_value."' ");

                      while($row1 = $ymmquery1->fetch ())
                      {
                        $model_map=$row1['model'];

                        echo '<option value='.'"'.$row['value'].'"'.' >'.$model_map.' </option>';
                      }

                      //echo '<option id='.$attributeOptions[$nz]['value'].' value='.$row['value'].'>'.$attributeOptions[$nz]['label'].'</option>';
                     }

                  }
             }

         echo '</select>';
        }
      }   
    }

Answer 1

I have alternate solution for the same, please try this one.

create block in "catalog_product_view.xml" (where you want to display attribute)

 <referenceBlock name="product.info.main">
<block class="Magento\Catalog\Block\Product\View" name="attribue.name" template="Magento_Catalog::product/view/attribute_name.phtml" after="-"  /> </referenceBlock>

create "phtml" file under "Magento_Catalog::product/view/attribute_name.phtml"

<?php $product = $block->getProduct(); ?> // Get current product
<div>
    <?php 
        $data = explode(',',$product->getData('attribute_code'));
        foreach($data as $value):            
    ?>
        <?php 
        $attr = $product->getResource()->getAttribute('attribute_code');
        if ($attr->usesSource()): ?>
            <?php 
                $option_value = $attr->getSource()->getOptionText($value);
            ?>
            <p><?php echo $option_value; ?></p>

        <?php endif;?>
    <?php endforeach;?>
</div>

Answer 2

Using Directly Objectmanger is not a proper way to get result into magento 2 using __consturct() way to best manner to use magento 2.

1st way,

$obj = \Magento\Framework\App\ObjectManager::getInstance();
    $attributesList = $obj->create('Magento\Catalog\Model\Entity\Attribute')->loadByCode('catalog_product', 'activity');

        foreach ($attributesList->getSource()->getAllOptions() as $optionInfo) {
            //echo "<pre>";print_r($optionInfo);
            if($optionInfo['value'] != '')
                echo $optionInfo['value'].' = '.$optionInfo['label']."<br>";
        }

2nd Way Using BLock

Inside Block file

    protected $attributes;
        class Getattributes{
             public function __construct(
                \Magento\Framework\View\Element\Template\Context $context,
                \Magento\Catalog\Model\Entity\AttributeFactory $attributes
                array $data = []
            ) {
                $this->attributes = $attributes;
                parent::__construct($context, $data);
            }

            public function getMultiselectlist($resourcename,$attributename){
                $attributesList = $this->attributes->loadByCode($resourcename, $attributename);
                return $attributesList;
            }
        }

call inside template file

echo $block->getMultiselectlist('catalog_product',$attributes='activity');

please let me know if any issue

Answer 3

Use this method :

$product->getAttributeText('attribite_code');

if to check implementation you will see :

https://github.com/magento/magento2/blob/ed5c06d68ec4bf77ad6c03e0af28a133b1193b66/app/code/Magento/Catalog/Model/Product.php#L1798-L1809

   /**
     * Get attribute text by its code
     *
     * @param string $attributeCode Code of the attribute
     * @return string|array|null
     */
    public function getAttributeText($attributeCode)
    {
        return $this->getResource()->getAttribute($attributeCode)->getSource()->getOptionText(
            $this->getData($attributeCode)
        );
    }

For multiple attributes use foreach to loop attributes.

As you can see Magento 2 is super not optimized and broken. It can't resolve multiple attributes because of the good design.

 /**
         * Get a text for option value
         *
         * @param  string|int $value
         * @return string|bool
         */
        public function getOptionText($value)
        {
            $options = $this->getAllOptions();
            // Fixed for tax_class_id and custom_design
            if (count($options) > 0) {
                foreach ($options as $option) {
                    if (isset($option['value']) && $option['value'] == $value) {
                        return $option['label'] ?? $option['value'];
                    }
                }
            }
            // End
            if (is_scalar($value) && isset($options[$value])) {
                return $options[$value];
            }
            return false;
        }

Answer 4

use Magento\Catalog\Model\ResourceModel\Product as ProductResource;
...
public function __construct(
    ...
    ProductResource           $productResource
)
{
    ...
    $this->productResource = $productResource;
}

public function prepareProductAttributeOptions($product, $attributeCode)
{
    $result = [];
    $data = $product->getData($attributeCode);
    $optionsIds = [];
    if ($data) {
        $optionsIds = explode(',', $data);
    }

    foreach ($optionsIds as $optionId) {
        $attr = $this->productResource->getAttribute($attributeCode);
        if ($attr->usesSource()) {
            $option_value = $attr->getSource()->getOptionText($optionId);
            $result[] = $option_value;
        }
    }

    return implode(',', $result);

}