Validator

[yehiaazanki]

Why validator don`t respect formkey??

[lcuis]

Hello @yehiaazanki

search_choices is not supporting the standard Flutter forms features at the moment. However, this would be a great adaptation. Do you have any idea how this could be achieved?

[yehiaazanki]

Hello @yehiaazanki

search_choices is not supporting the standard Flutter forms features at the moment. However, this would be a great adaptation. Do you have any idea how this could be achieved?

hmm. ok

[martin-labanic]

@lcuis I think to accomplish this you need to change SearchChoices to extend FormField instead of StatefulWidget to get access to flutters form validation.

This a wrapper class I wrote as a workaround to get form validation working but its far from ideal.

import 'package:flutter/material.dart';
import 'package:search_choices/search_choices.dart';

class TTSearchChoices extends FormField<dynamic> {
  dynamic current_value;
  final ValueSetter<String>? on_changed;
  List<DropdownMenuItem<dynamic>>? items;
  bool is_expanded;
  bool display_clear_icon;
  bool auto_focus_search;
  Function? search_function;
  
  static String? _defaultValidator(dynamic v) {
    return null;
  }

  static void _defaultOnSaved(dynamic v) {
    // Currently does nothing, not sure if this is the correct way to do this but it appears to be working without it.
  }

  TTSearchChoices(
    this.current_value,
    this.on_changed,
    this.items,
    this.is_expanded,
    this.display_clear_icon,
    this.auto_focus_search,
    this.search_function,
    { FormFieldSetter<dynamic> on_saved = _defaultOnSaved,
      FormFieldValidator<dynamic> validator = _defaultValidator,
      AutovalidateMode autovalidate_mode = AutovalidateMode.onUserInteraction,
    }
  ): super(
    onSaved: on_saved,
    validator: validator,
    initialValue: current_value,
    autovalidateMode: autovalidate_mode,
    builder: (FormFieldState<dynamic> state) {
      
      void onChangedHandler(dynamic value) {
        state.didChange(value);
        if (on_changed != null) {
          on_changed(value as String);
        }
      }

      Widget result = SearchChoices.single(
        isExpanded: is_expanded,
        value: current_value,
        onChanged: onChangedHandler,
        items: items,
        displayClearIcon: display_clear_icon,
        padding: 0,
        autofocus: auto_focus_search,
        searchFn: search_function,
      );

      if (!state.isValid && state.errorText != null && state.errorText!.isNotEmpty) {
        result = Column(
          mainAxisSize: MainAxisSize.min,
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            result,
            Text(
              state.errorText ?? '',
              style: TextStyle(
                color: Colors.red[700],
                fontSize: 13.0,
              ),
            ),
          ]
        );
      }

      return Align(alignment: Alignment.topLeft, child: result);
    }
  );

}

[lcuis]

Thanks a lot @martin-labanic for your explanation and code.
I am looking forward to digging into this possibility.

[caniko]

+1

[lcuis]

Hello @martin-labanic ,

Version 2.1.2 contains an initial effort to adapt search_choices to extend FormField.

Can you please let me know whether this is what you expected?

[martin-labanic]

@lcuis Apologies for the late reply.

Unfortunately it does not work as expected as the failed validation does not get accounted for when a Form widgets validate function is called.

[lcuis]

Hi @martin-labanic !

No worries for the delay, I understand very well the time it takes to get back to such questions.

Thanks a lot for your answer!

Indeed, I was able to create a form with a validation that doesn't take into account the SearchChoices validator result.

I will try to understand why and how to change this behavior.

[lcuis]

It looks like version 2.1.5 is at least a partial solution to this request.

The new example "Validator in form" shows a form with single and multiple search_choices Widgets. If at least one of those widgets is not valid, the form is not valid either.

However, running the automated integration testing with Flutster made me realize that there are some specific situations where the call to didChange - necessary to update the value of the form field object and thus letting the validation work from a form perspective - fails when in multiple-future cases. I am not sure whether it is possible to overcome this constraint.

If and when you can, I would love to get your opinion on this functionality @martin-labanic

[lucasgm1997]

+1