Create custom block in custom theme

Question

I'm trying to create a custom block in the theme I created for Magento 2.1.8.

When I add the element to the default.xml layout, I got the following exception:

Exception #0 (Magento\Framework\Exception\LocalizedException): Invalid block type: frontend\Custom\Simple\Block\Services
Exception #1 (ReflectionException): Class frontend\Custom\Simple\Block\Services does not exist

In the Custom/Simple/Block/Services.php I have the following code:

<?php

namespace Custom\Simple\Block;
use Magento\Framework\View\Element\Template;

/**
* Services block
*/
class Services extends Template {
    public function getTitle() {
        return "Services";
    }
}

In the default.xml I've added this code:

<referenceContainer name="content">
    <block class="frontend\Custom\Simple\Block\Services" name="services.test" template="Custom_simple::test.phtml">
        <arguments>
            <argument name="something" xsi:type="string">Value</argument>
        </arguments>
    </block>
</referenceContainer>

I've tried to change the class to: Custom\Simple\Block\Services and I got the same error.

Thanks for your help!

Edit:

In the registration.php I have the following code:

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

Answer 1

First thing is that all this code should be located at app\code\Custom\Simple because you are creating a module not a theme.

And the other thing is you are giving wrong block & template location in the default.xml file give it as below & this file should be located at app\code\Custom\Simple\view\frontend\layout\default.xml

<referenceContainer name="content">
        <block class="Custom\Simple\Block\Services" name="services.test" template="Custom_Simple::test.phtml">
            <arguments>
                <argument name="something" xsi:type="string">Value</argument>
            </arguments>
        </block>
</referenceContainer>

and for the registration.php file there should be this code for the registration of the module & this file should be located at app\code\Custom\Simple\registration.php

<?php

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

Answer 2

Use

class="Custom\Simple\Block\Services"

Instead of

class="frontend\Custom\Simple\Block\Services"