Magento 2 – Fix Fatal Error: Call to a Member Function getAttributeText() on String

Your problem is here:

public function gridAction()
        {
        $this->loadLayout();
        $this->getResponse()->setBody(
        $this->getLayout()->createBlock('foo_bar/adminhtml_foo_grid')->toHtml()
        );
        }

'foo_bar/adminhtml_foo_grid' here

1. foo_bar is your confix.xml block name
2. adminhtml_foo_grid is the path of your Grid.php that means Vendor/Module/Block/Adminhtml/Foo/Grid.php

You forgot to declare some protected variables, you need to add the following

protected $uploader;
protected $adapterFactory;
protected $filesystem;

And also add the following to your __construct() :

$this->uploader = $uploader;
$this->adapterFactory = $adapterFactory;
$this->filesystem = $filesystem;