Checkbox form validation

Question

How can I validate a checkbox in a Flutter Form? Every other validation works fine, but the checkbox doesn\'t show an Error. Here is my code:

FormFi         


        

Answer 1

A cleaner solution to this problem is to make a class that extends FormField

Here is how I accomplished this:

class CheckboxFormField extends FormField {
  CheckboxFormField(
      {Widget title,
      FormFieldSetter onSaved,
      FormFieldValidator validator,
      bool initialValue = false,
      bool autovalidate = false})
      : super(
            onSaved: onSaved,
            validator: validator,
            initialValue: initialValue,
            autovalidate: autovalidate,
            builder: (FormFieldState state) {
              return CheckboxListTile(
                dense: state.hasError,
                title: title,
                value: state.value,
                onChanged: state.didChange,
                subtitle: state.hasError
                    ? Builder(
                        builder: (BuildContext context) =>  Text(
                          state.errorText,
                          style: TextStyle(color: Theme.of(context).errorColor),
                        ),
                      )
                    : null,
                controlAffinity: ListTileControlAffinity.leading,
              );
            });
}