framework/grid/RadioButtonColumn.php
protected function renderDataCellContent($model, $key, $index)
    {
        if ($this->content !== null) {
            return parent::renderDataCellContent($model, $key, $index);
        }

        if ($this->radioOptions instanceof Closure) {
            $options = call_user_func($this->radioOptions, $model, $key, $index, $this);
        } else {
            $options = $this->radioOptions;
            if (!isset($options['value'])) {
                $options['value'] = is_array($key) ? json_encode($key, JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE) : $key;
            }
        }
        $checked = isset($options['checked']) ? $options['checked'] : false;
        return Html::radio($this->name, $checked, $options);
    }
protected function renderDataCellContent($model, $key, $index)
    {
        if ($this->content !== null) {
            return parent::renderDataCellContent($model, $key, $index);
        }

        if ($this->radioOptions instanceof Closure) {
            $options = call_user_func($this->radioOptions, $model, $key, $index, $this);
        } else {
            $options = $this->radioOptions;
            if (!isset($options['value'])) {
                $options['value'] = is_array($key) ? json_encode($key, JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE) : $key;
            }
        }
        $checked = isset($options['checked']) ? $options['checked'] : false;
        return Html::radio($this->name, $checked, $options);
    }
{@inheritdoc}