CODEWITHSUNDEEP
flutterdartcart
Doing Things Occasionally
Doing Things Occasionally

Reputation: 800

Adding and Subtracting values after calculating Map values Flutter

I have a variable that I'm using in my cart that I'm using to update the total. When I navigate to my cart page, all the variable are calculated properly. I then am allowing users to update the quantity in the cart but, whenever I do, it seems like the value is calculated multiple times over and I cannot understand where the bug is.

Initially, I call this function to get the total:

void getCartTotal() {
  final cart = CartProvider.of(context);
  if (cart.orderDetails != null) {
    for (int i = 0; i < cart.orderDetails.length; i++) {
      setState(() {
        cartTotal +=
            (cart.orderDetails[i].price * cart.orderDetails[i].quantity);
      });

      print('There are ${cart.orderDetails.length} many items in the cart');
      minReached(cartTotal);
    }
  }
}

Then when updating the quantity in the cart, I use this counter:

      Counter(
                  color: Colors.white,
                  textStyle: TextStyle(
                      fontFamily: 'Poppins',
                      color: buddiesPurple,
                      fontSize: screenAwareSize(15, context)),
                  buttonSize: screenAwareSize(20, context),
                  minValue: 1,
                  maxValue: 10,
                  step: 1,
                  decimalPlaces: 0,
                  initialValue: cart.orderDetails[i].quantity,
                  onChanged: (num val) {
                    setState(() {
                      cart.orderDetails[i].quantity = val;
getCartTotal();
                    });
                  },
                ),

But whenever I try to update the cart (Increasing or decreasing), the values just double. Any help would be appreciated

Upvotes: 0

Views: 2728

Answers (1)

creativecreatorormaybenot
creativecreatorormaybenot

Reputation: 126734

I think that you need to reset your cartTotal back to 0 before looping over your items and adding their values to the total:

void getCartTotal() {
  final cart = CartProvider.of(context);
  if (cart.orderDetails != null) {
    cartTotal = 0;

    for (int i = 0; i < cart.orderDetails.length; i++) {
      setState(() {
        cartTotal +=
            (cart.orderDetails[i].price * cart.orderDetails[i].quantity);
      });

      print('There are ${cart.orderDetails.length} many items in the cart');
      minReached(cartTotal);
    }
  }
}

See where it says cartTotal = 0. If you do not do that, every time you increment a counter, the cartToal will double plus the increment.

Upvotes: 1

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