how to calculate total sum of list with in listview builder?

Question

I want to calculate the total price of list , how can i do that.

code for entering price.

     Container(
            width: 60.0,
            alignment: Alignment.centerRight,
            decoration: BoxDecoration(
                color: Colors.white,
                borderRadius: BorderRadius.circular(10.0)
            ),
            child: Padding(
              padding: const EdgeInsets.only(top: 10.0, left: 16.0),
              child: TextFormField(
                maxLength: 3,
                controller: _amountController,
                keyboardType: TextInputType.numberWithOptions(),
                decoration: InputDecoration(
                  counter: Offstage(),
                  border: InputBorder.none,
                ),
              ),
            ),

if i am using .fold then i am getting _addfromInteger error..

               Container(
                        height: 40.0,
                        width: 100.0,
                        decoration: BoxDecoration(
                            color: Colors.white,
                            borderRadius: BorderRadius.circular(10.0)

                        ),
                        child: Center(
                            child: Text(listdynamicWidget.fold(0, (prev, el) => prev + el.productAmount).toString()),
                        )
                        ),
                    ],
                  ),

Usually, this list should not be so long, so you can use a normal ListView instead of a list builder. — Hamed Rezaee
– Hamed Rezaee, Commented Dec 29, 2020 at 4:45
you can add a list of controllers instead of individual controllers then iterate through them to access text field values. — Hamed Rezaee
– Hamed Rezaee, Commented Dec 29, 2020 at 5:06
_addfromInteger error. means some value is null... print the list data and see which value is empty — griffins
– griffins, Commented Dec 29, 2020 at 5:21

Chandan · Accepted Answer · 2020-12-29 07:27:20Z

1

You should use TextField and onChanged at StatefulWidget like below.

TextField(
    onChanged: (inputText) {
      if (inputText.runtimeType == int) {
      // calculate method
      setState((){});
    }
  },
),

edited Dec 29, 2020 at 7:27

Chandan

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answered Dec 29, 2020 at 7:11

yamatatsu

213 bronze badges

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