Can't add js and css files to back office

Question

I want to add JS and CSS files to back office in my module. But I get error: Attempted to call an undefined method named \"registerStylesheet\" of class \"AdminModulesController

Answer 1

The explanation of which methods to use:

These are FrontController methods in PrestaShop 1.7: registerJavascript and registerStylesheet.

These are legacy (deprecated) FrontController methods in PrestaShop 1.7: addJS and addCSS.

These are AdminController methods in PrestaShop 1.7, 1.6, 1.5: addJS and addCSS.

So, the correct example to add a JS and a CSS files for a back-office (i.e. for AdminController) via a module class is:

public function hookActionAdminControllerSetMedia($params)
{ 
    // Adds your's CSS file from a module's directory
    $this->context->controller->addCSS($this->_path . 'views/css/example.css'); 

    // Adds your's JavaScript file from a module's directory
    $this->context->controller->addJS($this->_path . 'views/js/example.js');
}

For an additional information see my yet another answer how to register JavaScript in a back-office (in admin pages). I have updated it after this question.