Magento – Magento 2 – Move Product Details Tab Accordion

My approach is a little different but probably more future proof, in case of adding new tabs later on and changing the priority/order of these tabs.

I passed an argument for each tab via XML File in my themes XML file

...
<arguments>
    <argument name="priority" xsi:type="string">REPLACE WITH SOME NUMBER</argument>
</arguments>
...

So my themes XML file looks something like this:

<referenceBlock name="product.info.details">
        <referenceBlock name="product.info.description">
            <arguments>
                <argument name="priority" xsi:type="string">1</argument>
            </arguments>
        </referenceBlock>
        <referenceBlock name="product.attributes">
            <arguments>
                <argument name="priority" xsi:type="string">3</argument>
            </arguments>
        </referenceBlock>
        <referenceBlock name="reviews.tab">
            <arguments>
                <argument name="priority" xsi:type="string">4</argument>
            </arguments>
        </referenceBlock>
        <!-- MY OWN CUSTOM BLOCK ON THE SECOND POSITION -->
        <block class="Magento\Catalog\Block\Product\View\Description" name="product.features" as="features" template="product/view/features.phtml" group="detailed_info">
            <arguments>
                <argument translate="true" name="title" xsi:type="string">Features</argument>
                <argument name="priority" xsi:type="string">2</argument>
            </arguments>
        </block>
        <!-- MY OWN CUSTOM BLOCK ENDS HERE -->
    </referenceBlock>

Further more we have to adjust the details.phtml, so copy it from

<magento_root>/vendor/magento-catalog-view/frontend/templates/product/view/details.phtml

to

<magento_root>/app/design/frontend/<Vendor>/<theme>/Magento_Catalog/templates/product/view/details.phtml

Please keep in mind that magento's own details.phtml could be changed in future Magento versions or patches. These changes should be also applied to your theme's details.phtml

We now need to get the priority which we passed on via the XML file.

<?php
/**
 * Copyright © 2016 Magento. All rights reserved.
 * See COPYING.txt for license details.
 */

// @codingStandardsIgnoreFile

?>
<?php if ($detailedInfoGroup = $block->getGroupChildNames('detailed_info', 'getChildHtml')):?>
    <div class="product info detailed">
        <?php $layout = $block->getLayout(); ?>
        <?php
            # We create a new array;
            $newPriority = array();
            # forEach the original $detailedInfoGroup Array;
            foreach ($detailedInfoGroup as $name){
                $alias = $layout->getElementAlias($name);
                # Get the priority which we applied via xml file
                # If no priority is applied via xml file then just set it to 10
                $priority = $block->getChildData($alias,'priority') ? $block->getChildData($alias,'priority') : '10';
                # variables pushed into new two-dimensional array
                array_push($newPriority, array($name, $priority));
            }
            # Sort array by priority
            usort($newPriority, function($a, $b) {
                return $a['1'] <=> $b['1'];
            });
        ?>
        <div class="product data items" data-mage-init='{"tabs":{"openedState":"active"}}'>
            <?php
            # Delete the original forEach statement
            #foreach ($detailedInfoGroup as $name)
            foreach ($newPriority as $name):?>
                <?php
                    # rename $name[0] to $name because it's a two-dimensional array
                    # No further changes to this file, it works as explained
                    $name = $name[0];
                    $html = $layout->renderElement($name);
                    if (!trim($html)) {
                        continue;
                    }
                    $alias = $layout->getElementAlias($name);
                    $label = $block->getChildData($alias, 'title');
                ?>
                <div class="data item title"
                     aria-labeledby="tab-label-<?php /* @escapeNotVerified */ echo $alias;?>-title"
                     data-role="collapsible" id="tab-label-<?php /* @escapeNotVerified */ echo $alias;?>">
                    <a class="data switch"
                       tabindex="-1"
                       data-toggle="switch"
                       href="#<?php /* @escapeNotVerified */ echo $alias; ?>"
                       id="tab-label-<?php /* @escapeNotVerified */ echo $alias;?>-title">
                        <?php /* @escapeNotVerified */ echo $label; ?>
                    </a>
                </div>
                <div class="data item content" id="<?php /* @escapeNotVerified */ echo $alias; ?>" data-role="content">
                    <?php /* @escapeNotVerified */ echo $html; ?>
                </div>
            <?php endforeach;?>
        </div>
    </div>
<?php endif; ?>

So you see: You just have to add a few lines and can always change the priority/order of the tabs via the xml file, you don't have to change the details.phtml in future anymore.

Best Effort is use to move element. You can simple call inside default.xml file using move element. No need to rearrange your block inside container.

<move element="sourcename" destination="destinationname" after|before="">

This is the best practice in magento 2.