Update subtotal, global $cart variable?

[satjunasa]

I am trying to display the total number of items currently in the cart in my menu, but the $cart and $cart_qties both return NULL. Is there a way to get this info?

 

Also when in cart summary the subtotal of a item doesn't update when you click the + to increase the quantity. It only updates when you refresh the page. The total price does automatically update.

 

I am using prestashop 1.7.

 

Thanks.