Hi guys, I am attempting to create a shopping cart, however I am trying to make it a little more advanced.

This is an image of the shopping cart screen. Currently when I add a new item to the shopping list my + and - buttons are altering all of the items quantities within the shopping cart because the variable is the same. I was wondering if it would be possible to make it so that every time a new item is added to the gallery it assigns the variable to a unique variable. The example:
UpdateContext({quantity:TextInput4 +1})
This is the code inside of the + and - button (With the subtract being -1 instead of +1), then I call that variable into the textbox. Is it possible to create a loop or something similar that says for each item in the gallery assign the quantity variable to quantity1, quantity2 etc.
I realise that it would be easier to just remove the + and - buttons and just allow the user to enter the value but I would like to explore this option if it is possible.
Thanks in advance guys!