Question 203856 in Flutter Question posted in
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Is there any way to sum items from list API in Flutter shopping cart page?

I have to calculate the sub-total amount, shipping cost, and packaging cost and show them on CartView page.
I fetched data from API and I got a price, quantity, shipping cost, etc. There subtotal = price* quantity.
There is my code:

controller.obx((response) => response != null
                  ? Container(
                      child: ListView.builder(
                        scrollDirection: Axis.vertical,
                        shrinkWrap: true,
                        itemCount: response.length,
                        itemBuilder: (BuildContext context, index) {
                          var subTotal =
                              response[index].quantity!.toDouble() *
                                  response[index].product!.price!.toDouble();
                          return Column(
                            children: [
                              ListTile(
                                title: Text('Sub Total'.tr.toString()),
                                trailing: Text(subTotal.toString()),
                              ),
                              ListTile(
                                title: Text('Discount'.tr.toString()),
                                trailing: Text(
                                    '00'), /*${response[index].product!.price!.toInt()+response[index+1].product!.price!.toInt()}*/
                              ),
                              ListTile(
                                title: Text('Delivery Charge'.tr.toString()),
                                trailing: Text(
                                    '${response[index].quantity!.toDouble() * response[index].product!.shippingCost!.toDouble()} tk'), /*${response[index].product!.price!.toInt()+response[index+1].product!.price!.toInt()}*/
                              ),
                              ListTile(
                                title: Text('Packaging Cost'.tr.toString()),
                                trailing: Text( response[index].basketQty == '1'? '50': '120'),
                              ),
                            ],
                          );
                        },
                      ),
                    )
                  : Text('')),

In this way I got subtotal for first item then got another subtotal for second item and so on, but I need just one subtitle that will have all item subtotal in sum form.

Tags:

2

Answers


  1. 0

    Use a global variable subTotal and keep adding the the total of each item in it.

     var subTotal = 0;                                  
 controller.obx((response) => response != null
              ? Container(
                  child: ListView.builder(
                    scrollDirection: Axis.vertical,
                    shrinkWrap: true,
                    itemCount: response.length,
                    itemBuilder: (BuildContext context, index) {
                      subTotal +=
                          response[index].quantity!.toDouble() *
                              response[index].product!.price!.toDouble();
                      return Column(
                        children: [
                          ListTile(
                            title: Text('Sub Total'.tr.toString()),
                            trailing: Text(subTotal.toString()),
                          ),
                          ListTile(
                            title: Text('Discount'.tr.toString()),
                            trailing: Text(
                                '00'), /*${response[index].product!.price!.toInt()+response[index+1].product!.price!.toInt()}*/
                          ),
                          ListTile(
                            title: Text('Delivery Charge'.tr.toString()),
                            trailing: Text(
                                '${response[index].quantity!.toDouble() * response[index].product!.shippingCost!.toDouble()} tk'), /*${response[index].product!.price!.toInt()+response[index+1].product!.price!.toInt()}*/
                          ),
                          ListTile(
                            title: Text('Packaging Cost'.tr.toString()),
                            trailing: Text( response[index].basketQty == '1'? '50': '120'),
                          ),
                        ],
                      );
                    },
                  ),
                )
              : Text('')),
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  2. 0

    You can wrap your Container inside the Column and you can use fold method on your response (iterable) . Your code would look something like this

    controller.obx((response) => response != null
                  ? Column(
              children: [
                Container(
                  child: ListView.builder(
                    scrollDirection: Axis.vertical,
                    shrinkWrap: true,
                    itemCount: response.length,
                    itemBuilder: (BuildContext context, index) {
                      var subTotal = response[index].quantity!.toDouble() *
                          response[index].product!.price!.toDouble();
                      return Column(
                        children: [
                          ListTile(
                            title: Text('Sub Total'.tr.toString()),
                            trailing: Text(subTotal.toString()),
                          ),
                          ListTile(
                            title: Text('Discount'.tr.toString()),
                            trailing: Text(
                                '00'), /*${response[index].product!.price!.toInt()+response[index+1].product!.price!.toInt()}*/
                          ),
                          ListTile(
                            title: Text('Delivery Charge'.tr.toString()),
                            trailing: Text(
                                '${response[index].quantity!.toDouble() * response[index].product!.shippingCost!.toDouble()} tk'), /*${response[index].product!.price!.toInt()+response[index+1].product!.price!.toInt()}*/
                          ),
                          ListTile(
                            title: Text('Packaging Cost'.tr.toString()),
                            trailing: Text(response[index].basketQty == '1'
                                ? '50'
                                : '120'),
                          ),
                        ],
                      );
                    },
                  ),
                ),
                 ListTile(
                  title: Text("Total :",),
                  trailing: Text(response.fold<double>(
                      0,
                          (previousValue, element) =>
                      previousValue +
                          element.quantity!.toDouble() *
                              element.product!.price!.toDouble()).toString(),),
                ),
              ],
            )
          : Text('')),
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