public function getDefaultItem()
 {
     return function ($index, $label, $name, $checked, $value) {
         $inputOptions = $this->inputOptions;
         $inputOptions['value'] = ArrayHelper::getValue($inputOptions, 'value', $value);
         return Html::tag('div', Checkbox::widget(['name' => $name, 'label' => $label, 'checked' => $checked, 'inputOptions' => $inputOptions, 'labelOptions' => $this->labelOptions]), ['class' => 'field']);
     };
 }
 public function checkbox($options = [], $enclosedByLabel = true)
 {
     $this->parts['{label}'] = '';
     $this->parts['{input}'] = Checkbox::widget(['class' => Checkbox::className(), 'model' => $this->model, 'attribute' => $this->attribute, 'options' => $options, 'label' => Html::activeLabel($this->model, $this->attribute, $this->labelOptions)]);
     return $this;
 }