Multiply value of textformfield in Listview and get the sum of it - flutter

Question

I have two textformfields in my listview. I want to get the value from each of them, multiply for each index and ultimately get the total value. It's more like an invoice. This will be done onChange of the textformfields. I have the following code which does not return the correct output.
class _OrderBookingState extends State<OrderBooking> {
#override
Widget build(BuildContext context) {
TextEditingController controller = new TextEditingController();
List<TextEditingController> _textFieldRateControllers = new List();
List<TextEditingController> _textFieldQtyControllers = new List();
var productCount = 0;
return Scaffold(
appBar: AppBar(
title: Center(child: Text(widget.shop.shopName)),
),
body: Column(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
children: <Widget>[
Container(
child: StreamBuilder<List<ProductModel>>(
stream: DatabaseService().productList,
builder: (context,snapshot){
productCount = snapshot.data.length;
if(snapshot.hasData){
return Flexible(
child: ListView.builder(
scrollDirection: Axis.vertical,
shrinkWrap: true,
itemCount: snapshot.data.length,
itemBuilder: (context, index){
_textFieldQtyControllers.add(new TextEditingController());
_textFieldRateControllers.add(new TextEditingController());
_textFieldRateControllers[index].text = snapshot.data[index].rate;
_textFieldQtyControllers[index].text = "0";
countTotal(){
var totalSum = 0.0;
_textFieldQtyControllers.forEach((element) {
var rateDouble = double.parse(_textFieldRateControllers[index].text);
var qtyDouble = double.parse(_textFieldQtyControllers[index].text);
var multiple = rateDouble*qtyDouble;
totalSum += multiple;
//calculateTotal(element, _textFieldRateControllers[index].text, _textFieldQtyControllers[index].text);
}
);
print("Total is $totalSum" );
}
return Padding(
padding: EdgeInsets.only(top: 8.0),
child: Card(
margin: EdgeInsets.fromLTRB(10.0, 6.0, 10.0, 0.0),
child: ListTile(
leading: CircleAvatar(
radius: 25.0,
backgroundColor: Colors.deepOrangeAccent,
),
title: Row(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children: <Widget>[
Container(
width: 175,
child: Text(snapshot.data[index].productName,),
),
// Expanded(child: Container(
// width: 10,
// child: Center(child: Text(snapshot.data[index].productName,)))),
SizedBox(width: 5,),
Expanded(child: Container(
width: 10,
child: TextFormField(
controller: _textFieldRateControllers[index],
textAlign: TextAlign.center,
onChanged: (text){
countTotal();
},
//onChanged: (text){calculateTotal(productCount, _textFieldRateControllers[index].text, _textFieldQtyControllers[index].text);},
),
),
),
SizedBox(width: 5,),
Expanded(child: TextFormField(
controller: _textFieldQtyControllers[index],
textAlign: TextAlign.center,
onChanged: (text){
countTotal();
//calculateTotal(productCount, _textFieldRateControllers[index].text, _textFieldQtyControllers[index].text);
},
)
)
],
),
subtitle: Text('MRP ' + snapshot.data[index].mrp),
),
),
);
}
),
);
}else{
return Loading();
}
}
),
),
Container(
margin: EdgeInsets.fromLTRB(10.0, 6.0, 10.0, 0.0),
child: Row(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
children: <Widget>[
Text(
"Total Value: 0/-",
style: TextStyle(fontSize: 20, fontWeight: FontWeight.bold,backgroundColor: Colors.greenAccent)
),
RaisedButton(
child: Text("Save",style: TextStyle(fontSize: 18.0),),
color: Colors.green,
textColor: Colors.white,
highlightColor: Colors.lightGreenAccent,
onPressed: (){
//print(_textFieldQtyControllers[1].text);
},
)
],
),
)
],
),
);
}
}
As per the image it should return (260+85+67 = 412) which I'm not getting.Please let me know how to achieve this.

Answer 1

The reason is you are assigning qty as zero in itembuilder of your listview:-
_textFieldQtyControllers[index].text = "0";
So replace it with 10 as per your image:-
_textFieldQtyControllers[index].text = "10";