对此问题的一种更清洁的解决方案是，创建一个扩展 FormField< bool>

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

这是我的完成方式:

class CheckboxFormField extends FormField<bool> {
  CheckboxFormField(
      {Widget title,
      FormFieldSetter<bool> onSaved,
      FormFieldValidator<bool> validator,
      bool initialValue = false,
      bool autovalidate = false})
      : super(
            onSaved: onSaved,
            validator: validator,
            initialValue: initialValue,
            builder: (FormFieldState<bool> 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,
              );
            });
}