Error when supplying an initial value to TextField - flutter

Question

I am facing a problem with TextField, since I am working hand in hand with TextEditingController()..text and onChanged, but when entering a new data, it is not reflected in the TextField. I made a print inside the onChanged this same one recognizes a new entry but the value to initiate continues without being updated. Inside the onChanged, I have a function which is in charge of validating what is entered and returning an error if necessary. When I comment the instruction before mentioned the TextField already allows to enter and to update what the user enters.
I hope you can help me, a feedback, tutorial, etc.
I would appreciate it.
TextField Code:
CustomTextField(
controller: TextEditingController()..text = datumAdministrative.name,
placeholder: Constants.selectDate,
helperText: Constants.requiredData,
keyboardType: TextInputType.text,
enable: true,
errorText: validationForm.name.error,
textInputAction: TextInputAction.next,
textCapitalization: TextCapitalization.sentences,
onChanged: (String value) {
validationForm.changeName(value);
},
);
ValidationForm Code:
void changeName(String value) {
String pattern = r'(^[a-zA-Z ]*$)';
RegExp regExp = new RegExp(pattern);
regExp.hasMatch(value)
? _name = ValidationItem(value, null)
: _name = ValidationItem(null, Constants.nameAdministrativeMessage);
notifyListeners();
}

Answer 1

Try Using : TextController(text: "<Required Text>")
Also does the validation have to be every single time the user enter any word ?
If not, you can try validation everything at the end.
If you are trying to use reactive validation, make sure your CustomTextField is wrapped with the widget which is responsible for rebuilding the UI.. something like Consumer() when using provider package

Answer 2

The problem is probably caused because the TextEditingController object is getting discarded by the rebuilds made by Flutter because you are instantiating the TextEditingController inside a build method. You should save the instance of your controller elsewhere, like in a state object as shown by the official docs or in your case, you can create it and get it from your validationForm.
This is the example in the docs:
/// This is the private State class that goes with MyStatefulWidget.
class _MyStatefulWidgetState extends State<MyStatefulWidget> {
/// save the [TextEditingController] instance
final TextEditingController _controller = TextEditingController();
...
#override
Widget build(BuildContext context) {
return Scaffold(
body: Container(
alignment: Alignment.center,
padding: const EdgeInsets.all(6),
child: TextFormField(
controller: _controller, // User your instance
decoration: const InputDecoration(border: OutlineInputBorder()),
),
),
);
}
}
Possible solution in your case:
CustomTextField(
controller: validationForm.myTextController,
placeholder: Constants.selectDate,
...