public function excel()
    {
        $PHPExcel =  new \PHPExcel();
        $PHPSheet = $PHPExcel->getActiveSheet();
        // 设置个表格标题
        $PHPSheet->setTitle("代理商");
        $PHPSheet->setCellValue("A1", "ID");
        $PHPSheet->setCellValue("B1", "分类名称");
        $PHPSheet->setCellValue("C1", "图片");
        $PHPSheet->setCellValue("D1", "状态");

        //设置表格宽度
        $PHPExcel->getActiveSheet()->getColumnDimension('A')->setWidth(20);
        $PHPExcel->getActiveSheet()->getColumnDimension('B')->setWidth(20);
        $PHPExcel->getActiveSheet()->getColumnDimension('C')->setWidth(20);
        $PHPExcel->getActiveSheet()->getColumnDimension('D')->setWidth(80);
        $i = 2;
        $list = \app\admin\model\Category::select();
        $list = (new \think\Collection($list))->toArray();
        $list = $this->get_cate_list($list);
        foreach ($list as $key => $value) {
            $PHPSheet->setCellValue('A' . $i, '' . $value['id']);
            $PHPSheet->setCellValue('B' . $i, '' . $value['cate_name']);

            $PHPSheet->setCellValue('D' . $i, '' . $value['is_show']);
            $img = Db::table('pyg_category')->where('id', $value['id'])->field('image_url')->find();
            $objDrawing[$key] = new \PHPExcel_Worksheet_Drawing();
            $objDrawing[$key]->setPath('.' . $img['image_url']);   //这里拼接 . 是因为要在根目录下获取

            $objDrawing[$key]->setHeight(20);//照片高度
            $objDrawing[$key]->setWidth(70); //照片宽度

            $objDrawing[$key]->setCoordinates('C' . $key);

            // 图片偏移距离
            $objDrawing[$key]->setOffsetX(12);
            $objDrawing[$key]->setOffsetY(12);
            $objDrawing[$key]->setWorksheet($PHPExcel->getActiveSheet());
//            $PHPSheet->setCellValue('D'.$i,''.$value['image_input']);
            $i++;

        }

        $PHPExcel->setActiveSheetIndex(0);
        $file_name = date('Y-m-d_H:i:s') . '表格' . '.xls';
        $objWriter = \PHPExcel_IOFactory::createWriter($PHPExcel, "Excel2007");
        header('Content-Disposition: attachment;filename=' . $file_name);
        header('Content-Type: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet');
        header('Cache-Control: max-age=0');
        $objWriter->save("php://output");


    }

    function get_cate_list($data,$pid=0,$level=0){
        $info=[];
        foreach ($data as $v){
            if($v['pid']==$pid){
                $v['level']= $level;
                $info[]=$v;
                $this->get_cate_list($data,$v['id'],$level+1);

            }
        }
        return $info;
    }