Magento2 - custom _theme.xml

Question

I tried to change the _theme.xml of a custom theme based on the blank theme like described in this article: http://devdocs.magento.com/guides/v2.0/frontend-dev-guide/css-topics/css-practice.html

But if I refresh the frontend it doesn't changed. The cache is disabled.

Heres my code: composer.json

{
"name": "my/blank",
"description": "N/A",
"require": {
    "php": "~5.5.0|~5.6.0|~7.0.0",
    "magento/theme-frontend-blank": "100.0.*",
    "magento/framework": "100.0.*"
},
"type": "magento2-theme",
"version": "100.0.2",
"license": [
    "OSL-3.0",
    "AFL-3.0"
],
"autoload": {
    "files": [
        "registration.php"
    ]
}

}

registration.php

\Magento\Framework\Component\ComponentRegistrar::register(
\Magento\Framework\Component\ComponentRegistrar::THEME,
'frontend/my/blank',
__DIR__

);

theme.xml

<theme xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Config/etc/theme.xsd">
<title>My Blank</title>
<parent>Magento/blank</parent>
<media>
    <preview_image>media/preview.jpg</preview_image>
</media>

Answer 1

For custom theme apply please follow below steps

Create a theme directory

To create the directory for your theme:

1. Go to /app/design/frontend.
2. Create a new directory named according to your vendor name: /app/design/frontend/.

3. Under the vendor directory, create a directory named according to your theme. (e.g. mytheme)

   in theme directory structure looks like this

app/design/frontend/
├── <Vendor>/ (my)
│   │   ├──...<theme>/  (themename)
│   │   │   ├── ...etc
│   │   │   ├── ...media
│   │   │   ├── ...web
|   |   |   |    ├── ...css
|   |   |   |    ├── ...images
|   |   |   |    ├── ...js
│   │   │   ├── registration.php
│   │   │   ├── theme.xml

Declare your theme

Add or copy from an existing theme.xml to your theme directory

app/design/frontend/<Vendor>/<theme>

Configure it using the following example:

<theme xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Config/etc/theme.xsd">
     <title>blank</title> <!-- your theme's name -->
     <parent>Magento/blank</parent> <!-- the parent theme, in case your theme inherits from an existing theme -->
     <media>
         <preview_image>media/preview.jpg</preview_image> <!-- the path to your theme's preview image -->
     </media>
 </theme>

Register your theme

in your theme directory add a registration.php file with the following content:

<?php
/**
* Copyright © 2015 Magento. All rights reserved.
* See COPYING.txt for license details.
*/
\Magento\Framework\Component\ComponentRegistrar::register(
    \Magento\Framework\Component\ComponentRegistrar::THEME,
    'frontend/<Vendor>/<theme>',
    __DIR__
);

---

Where is your vendor name, is the theme code.

Configure Your theme

<your Magento install dir>dev\tools\grunt\configs\themes.js

    themename: {
        area: 'frontend',
        name: 'my/themename',
        locale: 'en_US',
        files: [
            'css/styles-m',
            'css/styles-l'
        ],
        dsl: 'less'
    },

flush your cache apply your theme from admin Store > configuration > design

Answer 2

once you create custom theme two thing has to be done

1.clear cache
2. login to admin side then only it will add your custom theme