Luma child not appearing in Admin

Question

I am trying to set up a child theme of Luma but it's not appearing in the Admin area. I have checked I have it set up correctly, I think I have. Main area I'm worried about is that the original Luma files are in vendor/magento/theme-frontend-luma and I have set up the child theme in app/design/frontend. Does this make a difference? Should I be setting the child theme up in vendor also?

Files are as follows:

app/design/frontend/Mytheme/luma_child/theme.xml

<theme xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:noNamespaceSchemaLocation="urn:magento:framework:Config/etc/theme.xsd">
    <title>Luma Child</title>
    <parent>Magento/luma</parent>
    <media>
        <preview_image>media/preview.png</preview_image>
    </media>
</theme>

app/design/frontend/Mytheme/luma_child/registration.php

<?php \Magento\Framework\Component\ComponentRegistrar::register(\Magento\Framework\Component\ComponentRegistrar::THEME, 'frontend/Mytheme/luma_child', __DIR__);

app/design/frontend/Mytheme/luma_child/composer.json

{
    "name": "Mytheme/theme-frontend-luma-child",
    "description": "N/A",
    "require": {
        "php": "~5.5.0|~5.6.0|~7.0.0|~7.1.0|~7.2.0|~7.3.0",
        "magento/luma": "100.0.*",
        "magento/framework": "100.0.*"
    },
    "type": "magento2-theme",
    "version": "100.0.1",
    "license": [
        "OSL-3.0",
        "AFL-3.0"
    ],
    "autoload": {
        "files": [
            "registration.php"
        ]
    }
}

Within Mytheme/luma_child I also have web folder with css, image, fonts and js folders, just copied from the vendor luma folder.

I have run composer update and magento setup:upgrade and a variety of other command line operations over the last few days since I set this up and it hasn't appeared.

What am I missing? Thanks!

Answer 1

You have issue in your registration.php. You missed use It should be like:

<?php
use \Magento\Framework\Component\ComponentRegistrar;
ComponentRegistrar::register(ComponentRegistrar::THEME, 'frontend/Mytheme/luma_child', __DIR__);