How to change backend admin theme in Magento 2.0.7 +

Question

How and what to add to be able to override any of the magento-backend module templates and what is the sequence order of the custom module or theme

Answer 1

I followed this solution https://magento.stackexchange.com/a/96559/23344 and it works like a charm.

Below its step 3 improved.

I created the module in \app\code\XXX\Backend\ and within the files:

\app\code\XXX\Backend\registration.php

<?php

 \Magento\Framework\Component\ComponentRegistrar::register(
    \Magento\Framework\Component\ComponentRegistrar::MODULE, 'XXX_Backend', __DIR__
);

\app\code\XXX\Backend\etc\module.xml

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Module/etc/module.xsd">
    <module name="XXX_Backend" setup_version="1.0.0">
        <sequence>
            <module name="Magento_Backend"/>
        </sequence>
    </module>
</config>

\app\code\XXX\Backend\etc\di.xml

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
    <type name="Magento\Theme\Model\View\Design">
        <arguments>
            <argument name="themes" xsi:type="array">
                <item name="frontend" xsi:type="string">Magento/luma</item>
                <item name="adminhtml" xsi:type="string">XXX/backend</item>
            </argument>
         </arguments>
    </type>
</config>

Finally run php bin/magento setup:upgrade

Now you could extend adminhtml template, i customize \app\design\adminhtml\XXX\backend\Magento_Sales\templates\items\column\name.phtml and it works.

Answer 2

A follow-up to Luca's answer that might help others like who only look to extend the layout:

1. in your newly created app that sets the adminhtml theme, in etc/module.xml, you have use:

   <module name="Magento_Theme"/>

as a sequence.

2. you have to have some css file or other static content in app/design/adminhtml/name/theme/web (I placed the _theme.less file in /web/css/source). You can inspect the checkThemesInput method in Magento\Deploy\Console\Command\DeployStaticContentCommand to find out why.