YII2 ExcelGrid

<?php
namespace frontend\components\ExcelGrid;

use Yii;
use Closure;
use yii\i18n\Formatter;
use yii\base\InvalidConfigException;
use yii\helpers\Url;
use yii\helpers\Html;
use yii\helpers\Json;
use yii\helpers\ArrayHelper;
use yii\widgets\BaseListView;
use yii\base\Model;
use \PHPExcel;
use \PHPExcel_IOFactory;
use \PHPExcel_Settings;
use \PHPExcel_Style_Fill;
use \PHPExcel_Writer_IWriter;
use \PHPExcel_Worksheet;

class ExcelGrid extends \yii\grid\GridView
{
    public $columns_array;
    public $properties;
    public $filename='excel';
    public $extension='xlsx';
    private $_provider;
    private $_visibleColumns;
    private $_beginRow = 1;
    private $_endRow;
    private $_endCol;
    private $_objPHPExcel;
    private $_objPHPExcelSheet;
    private $_objPHPExcelWriter;
    public function init(){
        parent::init();
    }
    public function run(){
        //$this->test();
        $this->init_provider();
        $this->init_excel_sheet();
        $this->initPHPExcelWriter('Excel2007');
        $this->generateHeader();
        $row = $this->generateBody();
        $writer = $this->_objPHPExcelWriter;
        $this->setHttpHeaders();
        $writer->save('php://output');
        Yii::$app->end();
        //$writer->save('test.xlsx');
        parent::run();
    }

    public function init_provider(){
        $this->_provider = clone($this->dataProvider);
    }
    public function init_excel_sheet(){
        $this->_objPHPExcel=new PHPExcel();

        $creator = '';
        $title = '';
        $subject = '';
        $description = 'Excel Grid Generated';
        $category = '';
        $keywords = '';
        $manager = '';
        $company = 'CODE';
        $created = date("Y-m-d H:i:s");
        $lastModifiedBy = '';
        @extract($this->properties);
        $this->_objPHPExcel->getProperties()
            ->setCreator($creator)
            ->setTitle($title)
            ->setSubject($subject)
            ->setDescription($description)
            ->setCategory($category)
            ->setKeywords($keywords)
            ->setManager($manager)
            ->setCompany($company)
            ->setCreated($created)
            ->setLastModifiedBy($lastModifiedBy);
        $this->_objPHPExcelSheet = $this->_objPHPExcel->getActiveSheet();
    }
    public function initPHPExcelWriter($writer)
    {
        $this->_objPHPExcelWriter = PHPExcel_IOFactory::createWriter(
            $this->_objPHPExcel,
            $writer
        );
    }
    public function generateHeader(){
        $this->setVisibleColumns();
        $sheet = $this->_objPHPExcelSheet;
        $colFirst = self::columnName(1);

        $this->_endCol = 0;
        foreach ($this->_visibleColumns as $column) {
            $this->_endCol++;
            $head = ($column instanceof \yii\grid\DataColumn) ? $this->getColumnHeader($column) : $column->header;
            $cell = $sheet->setCellValue(self::columnName($this->_endCol) . $this->_beginRow, $head, true);
        }
        $sheet->freezePane($colFirst . ($this->_beginRow + 1));
    }

    public function generateBody()
    {
        $columns = $this->_visibleColumns;
        $models = array_values($this->_provider->getModels());
        if (count($columns) == 0) {
            $cell = $this->_objPHPExcelSheet->setCellValue('A1', $this->emptyText, true);
            $model = reset($models);
            return 0;
        }
        $keys = $this->_provider->getKeys();
        $this->_endRow = 0;
        foreach ($models as $index => $model) {
            $key = $keys[$index];
            $this->generateRow($model, $key, $index);
            $this->_endRow++;
        }

        // Set autofilter on
        $this->_objPHPExcelSheet->setAutoFilter(
            self::columnName(1) .
            $this->_beginRow .
            ":" .
            self::columnName($this->_endCol) .
            $this->_endRow
        );
        return ($this->_endRow > 0) ? count($models) : 0;
    }

    public function generateRow($model, $key, $index)
    {
        $cells = [];
        /* @var $column Column */
        $this->_endCol = 0;
        foreach ($this->_visibleColumns as $column) {
            if ($column instanceof \yii\grid\SerialColumn || $column instanceof \yii\grid\ActionColumn) {
                continue;
            } else {
                $format = $column->format;
                $value = ($column->content === null) ?
                    $this->formatter->format($column->getDataCellValue($model, $key, $index), $format) :
                    call_user_func($column->content, $model, $key, $index, $column);
            }
            if (empty($value) && !empty($column->attribute) && $column->attribute !== null) {
                $value =ArrayHelper::getValue($model, $column->attribute, '');
            }
            $this->_endCol++;
            $cell = $this->_objPHPExcelSheet->setCellValue(self::columnName($this->_endCol) . ($index + $this->_beginRow + 1),
                strip_tags($value), true);
        }
    }

    protected function setVisibleColumns()
    {
        $cols = [];
        foreach ($this->columns as $key => $column) {
            if ($column instanceof \yii\grid\SerialColumn || $column instanceof \yii\grid\ActionColumn) {
                continue;
            }
            $cols[] = $column;
        }
        $this->_visibleColumns = $cols;
    }

    public function getColumnHeader($col)
    {
        if(isset($this->columns_array[$col->attribute]))
            return $this->columns_array[$col->attribute];
        /* @var $model yii\base\Model */
        if ($col->header !== null || ($col->label === null && $col->attribute === null)) {
            return trim($col->header) !== '' ? $col->header : $col->grid->emptyCell;
        }
        $provider = $this->dataProvider;
        if ($col->label === null) {
            if ($provider instanceof ActiveDataProvider && $provider->query instanceof ActiveQueryInterface) {
                $model = new $provider->query->modelClass;
                $label = $model->getAttributeLabel($col->attribute);
            } else {
                $models = $provider->getModels();
                if (($model = reset($models)) instanceof Model) {
                    $label = $model->getAttributeLabel($col->attribute);
                } else {
                    $label =$col->attribute;
                }
            }
        } else {
            $label = $col->label;
        }
        return $label;
    }
    public static function columnName($index)
    {
        $i = $index - 1;
        if ($i >= 0 && $i < 26) {
            return chr(ord('A') + $i);
        }
        if ($i > 25) {
            return (self::columnName($i / 26)) . (self::columnName($i % 26 + 1));
        }
        return 'A';
    }

    protected function setHttpHeaders()
    {
        header("Cache-Control: no-cache");
        header("Expires: 0");
        header("Pragma: no-cache");
        header("x-man: 1");
        header("Content-Type: application/vnd.ms-excel");
        header("Content-Disposition: attachment; filename={$this->filename}.{$this->extension}");
        Yii::$app->response->format = \yii\web\Response::FORMAT_RAW;
    }
}
use:
<?php
    // \app\components\ExcelGrid::widget([ OR
    \bsource\gridview\ExcelGrid::widget([
        'dataProvider' => $dataProvider,
        'filterModel' => $searchModel,
        //'extension'=>'xlsx',
        //'filename'=>'excel',
        'properties' => [
            //'creator' =>'',
            //'title' => '',
            //'subject' => '',
            //'category' => '',
            //'keywords' => '',
            //'manager' => '',
            //'description'=>'BSOURCECODE',
            //'company' =>'BSOURCE',
        ],
        'columns' => [
            ['class' => 'yii\grid\SerialColumn'],
            'username',
            'createdby',
            'createdon',
        ],
    ]);


    Yii::$app->response->format = \yii\web\Response::FORMAT_RAW;
                    $this->renderPartial('stat',[
                                        'pList'=>..
                                        'exportType'=>'xlsx'
                                        ]);