Best practice for editing list items

I am designing a screen where the user can add products to a list. Now if a user decides that the quantity of an item on the list needs to be changed, or an item needs to be removed, what would be the best way to achieve this functionality? One way I thought of was to display a context menu on item long click. This menu will display options to delete or edit an item. But I'm also thinking if a better way is to have a text field appear directly on top of the item quantity, allowing users to change the quantity (or delete the item if the quantity is set to zero).