Flutter:Array of Textformfield validator not working - flutter

Question

I am working on an Array of Textformfields. The Array can be more than 50. I want to submit array of values to the server. The issue is when I execute validator it will be validating the first 8 in the array after that no error message. That too disappears when scrolling. I posted my code below:
void validateAndSave() {
final form = _formKey.currentState;
if (form.validate()) {
_formKey.currentState.save();
print('Form is valid');
}
else {
// _formKey.currentState.
print('form is invalid');
}
}
Widget singleItemList(int index) {
Item item = itemList[index];
return Container(
width: MediaQuery.of(context).size.width,
decoration: BoxDecoration(
color: Colors.white,
),
child:
Row(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
children: [
Expanded(
child:Padding(
padding: const EdgeInsets.fromLTRB(20, 10, 10, 20),
child: new TextFormField(
controller: _controller[index],
keyboardType: TextInputType.number,
//onSubmitted: (text) {
// takeNumber(text, item.id);
//},
validator: (value) {
if (value.isEmpty) return 'value is required';
},
decoration: new InputDecoration(
border: new OutlineInputBorder(
borderSide: new BorderSide(color: Colors.indigo)),
labelText: itemList[index].id,
suffixStyle: const TextStyle(color: Colors.red)
),
),
),
),
],
),
);
}
Please help me. Thanks in advance.
Regards,
Sathish

Answer 1

Have you considered replacing ListView.builder with Column?
Like this:
child: SingleChildScrollView(
child: Column(
children: List.generate(itemList.length, (index) {
if (itemList.isEmpty) {
return CircularProgressIndicator();
} else {
return singleItemList(index);
}
})
)
)
From ListView documentation:
Destruction
When a child is scrolled out of view, the associated element subtree, states and render objects are destroyed. A new child at the same position in the list will be lazily recreated along with new elements, states and render objects when it is scrolled back.