checkbox_formfield/lib/checkbox_icon_formfield.dart

import 'package:flutter/material.dart';

/// Use Icon as checkbox
class CheckboxIconFormField extends FormField<bool> {
  CheckboxIconFormField({
    Key? key,
    BuildContext? context,
    FormFieldSetter<bool>? onSaved,
    bool initialValue = false,
    ValueChanged<bool>? onChanged,
    AutovalidateMode? autovalidateMode,
    bool enabled = true,
    IconData trueIcon = Icons.check,
    IconData falseIcon = Icons.check_box_outline_blank,
    Color? trueIconColor,
    Color? falseIconColor,
    Color? disabledColor,
    double padding = 24.0,
    double? iconSize,
  }) : super(
          key: key,
          onSaved: onSaved,
          initialValue: initialValue,
          autovalidateMode: autovalidateMode,
          builder: (FormFieldState<bool> state) {
            trueIconColor ??= (context == null
                ? null
                : Theme.of(context).accentIconTheme.color);

            return Padding(
                padding: EdgeInsets.all(padding),
                child: state.value!
                    ? _createTappableIcon(state, enabled, trueIcon, onChanged,
                        trueIconColor, disabledColor, iconSize)
                    : _createTappableIcon(state, enabled, falseIcon, onChanged,
                        falseIconColor, disabledColor, iconSize));
          },
        );

  static Widget _createTappableIcon(
    FormFieldState<bool> state,
    bool enabled,
    IconData icon,
    ValueChanged<bool>? onChanged,
    Color? iconColor,
    Color? disabledColor,
    double? iconSize,
  ) {
    return IconButton(
      onPressed: enabled
          ? () {
              state.didChange(!state.value!);
              if (onChanged != null) onChanged(state.value!);
            }
          : null,
      icon: Icon(icon,
          color: enabled ? iconColor : disabledColor, size: iconSize),
    );
  }
}