int numberOfTextFields = 1;
List<TextEditingController> textFieldControllers = [];
final _numsFormKey = GlobalKey<FormState>();

Form(
                key: _numsFormKey,
                child: ListView.builder(
                  shrinkWrap: true,
                  itemCount: numberOfTextFields,
                  itemBuilder: (BuildContext? context, int? index) {
                    int i = index!   1;
                    return Row(
                      children: [
                        Container(
                          height: 52,
                          width: 140,
                          margin: EdgeInsets.only(left: 20.0, bottom: 10),
                         
                          child: TextFormField(
                            keyboardType: TextInputType.number,
                            // controller: textFieldControllers[index], //getting range error if i use this

                            decoration: InputDecoration(
                              hintText: 'Enter Number $i',
                              border: OutlineInputBorder(
                                borderRadius: BorderRadius.circular(5.0),
                              ),
                         
                            ),
                            style: TextStyle(
                              color: Color.fromARGB(255, 0, 0, 0),
                              fontWeight: FontWeight.w400,
                              fontSize: 24,
                            ),
                            validator: (value) {
                              if (value!.isEmpty) {
                                return "Enter or delete";
                              } else if (value.length > 12) {
                                return "Enter < 12 digits";
                              }
                              return null;
                            },
                            onSaved: (value) {}

in the IconButton onpressed used below:

onPressed: () {
                              print("number of boxes=$numberOfTextFields");
                              textFieldControllers
                                  .add(TextEditingController());
                              numberOfTextFields  ;
                              setState(() {
                              
                              });
                            }),

There is a Save Button, on clicking it:

_validateNums() async {
    if (_numsFormKey.currentState != null &&
        _numsFormKey.currentState!.validate()) {
      _numsFormKey.currentState!.save();
    } else {
      
    }
  }

And when I just print(value) or print(int.parse(value)) in the OnSaved{} it is printing all the values I entered.

 double totalsum = (textFieldControllers.fold(0,(previousValue, element) {return previousValue  
        double.tryParse(element.value.text)!;   double.parse(element.value.text); 

I am not able to use the above because I am getting range error while using controller in TextFormField.

How do I get the sum of all those values on clicking Save button. I tried using for loop but it did not work

CodePudding user response：

int numberOfTextFields = 1;
List<TextEditingController> textFieldControllers = [];

you declared you had 1 textfield, but at the beginning you have 0, you will always say you have more textfields that you do, that is why you get a range error.

Also, textFieldControllers is a list, which means it has a length method that keeps track of the number of items for you:

print("number of boxes=${textFieldControllers.length}");

...
itemCount: textFieldControllers.length,
itemBuilder: (BuildContext? context, int? index) {
...