php - 为什么for循环处理完后会出现进度条

Question

下面是我的脚本，我在其中放置了进度条来告诉用户正在处理的工作表数据的进度，问题是进度条在将 xls 保存到 csv 的整个过程完成后出现，请告诉我如何操作我可以修改以下内容，以便在处理当前工作表时进度条正确显示。谢谢，

 $excel = new Spreadsheet_Excel_Reader();
    $excel->setOutputEncoding('UTF-16');
    $excel->read('Student2.xls');
    $x=1;
    $sep = ",";

   $nbSheets = count($excel->sheets);
  echo $x." -  ".$nbSheets;

  $total = $nbSheets - 1;

for($i = 0; $i < $nbSheets; $i++) {


    // Calculate the percentation
    $percent = intval($i/$total * 100)."%";

    // Javascript for updating the progress bar and information
    echo '<script language="javascript">
    document.getElementById("progress").innerHTML="<div style=\"width:'.$percent.';background-color:#ddd;\">&nbsp;</div>";
    document.getElementById("information").innerHTML="'.$i.' row(s) processed.";
    </script>';

    // This is for the buffer achieve the minimum size in order to flush data
    echo str_repeat(' ',1024*64);

    // Send output to browser immediately
    flush();
    //sleep(1);

   ob_start();
    while($x<=$excel->sheets[$i]['numRows']) {
        $y=1;
        $row="";
        while($y<=$excel->sheets[$i]['numCols']) {
            $cell = isset($excel->sheets[$i]['cells'][$x][$y]) ? $excel->sheets[$i]['cells'][$x][$y] : '';
            $row.=($row=="")?"\"".$cell."\"":"".$sep."\"".$cell."\"";
            $y++;
        } 
        echo $row."\n"; 
        $x++;
    }
    $x = 1; $y = 1;
    $fp = fopen("data.csv",'a');
    fwrite($fp,ob_get_contents());
    fclose($fp);
    ob_end_clean();

}

echo "CSV file created successfully";
// Tell user that the process is completed
echo '<script language="javascript">document.getElementById("information").innerHTML="Process completed"</script>';

Answer 1

也许这可以解决您的问题:

questions#6556790 : echo-string-while-every-long-loop-iteration-flush-not-working

另外，为什么要使用输出缓冲区写入 data.csv 文件？正如它所说，输出缓冲区用于输出数据，因此在这种情况下，我认为简单地在 fwrite 中传递 $row."\n" 会更符合逻辑。功能。如果我在这里遗漏了什么，请纠正我。