Prestashop 1.6.1.4 - Add CSS to CMS Page of Module - css

Question

I am making a module that adds new tab in product edit page. The installation is Prestashop 1.6.1.4. The module adds a tab with some input fields that send data to mysql tables, but what I want to do is to style the fields a little bit, so that they look good. I am adding this in my module.php file:
public function install() {
if ($this->psversion() == 5 || $this->psversion() == 6)
{
if (parent::install() == false or !$this->registerHook('displayHeader') or !$this->registerHook('productFooter') or !$this->registerHook('displayAdminProductsExtra') or !$this->registerHook('actionProductUpdate') or !$this->registerHook('displayBackOfficeHeader'))
{
return false;
}
}
return true;
}
Then below this I put this code:
public function hookDisplayBackOfficeHeader($params) {
$this->context->controller->addCSS($this->_path.'views/css/adminsportsnutritionfadd.css');
}
But can't make the .css file appear. The file is in the right location, it has proper permissions and the owner of the file is www-data:www-data so this shouldn't be a permission issue. I have disable css combining in Prestashop as well as caching. Before reloading the page I am also deleting Prestashop's cache just in case, as well as I am deleting my brower's cache. Can somebody give me a hand in this?

Answer 1

Do like this:
public function hookBackOfficeHeader()
{
$this->context->controller->addCSS($this->_path.'views/css/adminsportsnutritionfadd.css');
}
For me it works like this:
$this->context->controller->addCSS($this->_path . 'views/css/back.css');
So the only difference is the css file name.

Answer 2

Not sure if you got this sorted or not, but...
I use this function within most of my modules to add
jQuery, Font-awesome, CSS & JS, then have it show ONLY on that module page...
public function hookDisplayBackOfficeHeader($params)
{
if(!(Tools::getValue('controller') == 'AdminModules'
&& Tools::getValue('configure') == 'MyModuleName')
){
return;
}
else
{
if ( method_exists($this->context->controller, 'addJquery') )
{
$this->context->controller->addJquery();
$this->context->controller->addCss('//maxcdn.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.min.css');
$this->context->controller->addCss($this->_path.'views/css/back.css');
$this->context->controller->addJs($this->_path.'views/js/back.js');
}
}
}