How to call specific validator instead of calling all the validators in same time by using `form.validate()`?

Question

This is the code :

if (form.validate()) {
          // Text forms was validated.
          if (mounted) {
            setState(() {
              _isButtonEnabled = true;
            });
          }
          form.save();
        }

I want to call specific validator for specific TextFormField

Answer 1

You will need to wrap each field you want to validate individually with a Form Widget and it's own key:

class TextFormFieldValidation extends StatefulWidget {
  @override
  _TextFormFieldValidationState createState() => _TextFormFieldValidationState();
}

class _TextFormFieldValidationState extends State<TextFormFieldValidation> {
  List<GlobalKey<FormState>> _formKeysList= [
    GlobalKey<FormState>(),
    GlobalKey<FormState>(),
  ];

  @override
  Widget build(BuildContext context) {
    return Column(
      children: <Widget>[
        Form(
          key: _formKeysList[0],
          child: TextFormField(
            validator: (value) => 'Bad',
          ),
        ),
        Form(
          key: _formKeysList[1],
          child: TextFormField(
            validator: (value) => 'Bad',
          ),
        ),
        RaisedButton(
          child: Text('Validate 1'),
          onPressed: () => _formKeysList[0].currentState.validate(),
        ),
        RaisedButton(
          child: Text('Validate 2'),
          onPressed: () => _formKeysList[1].currentState.validate(),
        ),
        RaisedButton(
          child: Text('Reset'),
          onPressed: () => _formKeysList.forEach((key) => key.currentState.reset()),
        ),
      ],
    );
  }
}