Error with Dependency Injection in widget

Question

I'm a new Magento 2 developer that's trying to create a widget with a picture in it and I've been following some tutorials to get started. I'm having some trouble though with dependency injection in the Block-class.

Here is the error:

Error filtering template: Recoverable Error: Argument 1 passed to Magento\Framework\View\Element\Template::__construct() must be an instance of Magento\Framework\View\Element\Template\Context, instance of Magento\Framework\ObjectManager\ObjectManager given, called in C:\xampp\htdocs\magento\vendor\magento\framework\ObjectManager\Factory\AbstractFactory.php on line 93 and defined in C:\xampp\htdocs\magento\vendor\magento\framework\View\Element\Template.php on line 128

The error obviously states that the constructor of the parent if acquiring the wrong information, but as far as I can tell I'm feeding it the correct data.

Here is my class:

<?php 
namespace X\Y\Block\Widget;

class CustomWidget extends \Magento\Framework\View\Element\Template
implements \Magento\Widget\Block\BlockInterface
{
    public function _toHtml()
    {
        $this->setTemplate('widget/custom_widget.phtml');
    }
} 

I've heard across the web though that using the _toHtml() function is bad practice and I should use the constructor instead, but that gives me the same effect. So far I've used these constructors:

protected function _construct()
{
    parent::_construct();
    $this->setTemplate('widget/custom_widget.phtml');
}

public function _construct(
    \Magento\Framework\View\Element\Template\Context $context,
    array $data = []
) {
    parent::_construct($context, $data);
    $this->setTemplate('widget/custom_widget.phtml');
}

I have also tried just setting

protected $_template = "widget/custom_widget.phtml";

but that generates the same result.

Have anyone seen this before? I have reinstalled Magento several times and my co-workers do not have this problem, so there's definitely something weird going on here.

Any help is much appreciated!

Answer 1

Check all of your namespaces, class names, file & folder names. This error can occurs when your namespace is like:

Vendor\Module\Block\SomeName\AnotherName

and your path to that file is like:

Vendor/Module/Block/Somename/Anothername

The second word starts from lowercase, in this situation, all can work fine before the compilation and doesn't work at all after, because the PHP array-keys is a case-sensitive but namespaces is not case-sensitive.

Here is similar problem with a controller Uncaught TypeError: Argument 1 passed to [...] must be an instance of

Answer 2

Try the following code, this worked for me on many occasions for creating widgets.

public function __construct(
        \Magento\Backend\Block\Template\Context $context,
        array $data = []
    )
    {
        parent::__construct($context, $data);
        $this->setTemplate('widget/custom-template.phtml');
    }