DropdownButtonFormField AutovalidateMode.always

Question

im trying to implement a DropdownButtonFormField to use the validator function, to show "error" message when is selected '1' but im doing something wrong because isnt working, this is my simple code, can you help me?

class ValidateDropdownButton extends StatefulWidget {
  State<ValidateDropdownButton> createState() =>
      _ValidateDropdownButtonState();
}

class _ValidateDropdownButtonState extends State<ValidateDropdownButton> {
  var data = [
    {'unit': '1', 'project': 'a'},
    {'unit': '1', 'project': 'b'},
    {'unit': '2', 'project': 'c'},
    {'unit': '2', 'project': 'd'},
  ];
  String? unit;

  Widget build(BuildContext context) {
    return Scaffold(
      body: Form(
        key: GlobalKey<FormState>(),
        autovalidateMode: AutovalidateMode.always,
        child: Column(
          children: [
            DropdownButtonFormField(
              value: unit,
              items: data
                  .map((e) => e['unit'])
                  .toSet()
                  .map((e) =>
                      DropdownMenuItem<String>(value: e, child: Text(e!)))
                  .toList(),
              onChanged: (String? value) => setState(() => unit = value),
              validator: (value) {
                if (value == '1') return 'error';
                return null;
              },
            ),
          ],
        ),
      ),
    );
  }
}

The DropdownButtonFormField has his own autovalidateMode, try adding the same always value — Jonathan Ixcayau, Jun 18 '22 at 22:38
yes, adding his own autovalidateMode works, thank you!, but its normal that the Form Widget has no effect on a FormField?(it's better remove it?), just curiosity. — José Luis Zarabanda Díaz, Jun 18 '22 at 23:41
I guess that is because AutovalidateMode.disabled is the default value — Jonathan Ixcayau, Jun 19 '22 at 00:36

DropdownButtonFormField AutovalidateMode.always

0 Answers0