Google-php-spreadsheet-API返回的不是工作表中的所有数据

如果工作表中有所有空单元格的行。例：

   cell1     cell2
row1 : not empty not empty
row2 : not empty not empty
row3 : empty     empty
row4 : not empty not empty
row5 : not empty not empty

谷歌返回的数据如下：

   cell1     cell2
row1 : not empty not empty
row2 : not empty not empty

如何获取带有空单元格的所有数据。我使用php-google-spreadsheet-client。我的代码：

....
$tokenArray = $client->fetchAccessTokenWithAssertion();
$accessToken = $tokenArray["access_token"];
$serviceRequest = new DefaultServiceRequest($accessToken);
ServiceRequestFactory::setInstance($serviceRequest);
$spreadsheetService = new Google'Spreadsheet'SpreadsheetService();
$tokenArray = $client->fetchAccessTokenWithAssertion();
$accessToken = $tokenArray["access_token"];
$serviceRequest = new DefaultServiceRequest($accessToken);
ServiceRequestFactory::setInstance($serviceRequest);
$spreadsheetService = new Google'Spreadsheet'SpreadsheetService();
$spreadsheetFeed = $spreadsheetService->getSpreadsheets();
$spreadsheet = $spreadsheetFeed->getByTitle('MySpreadsheet');
$worksheetFeed = $spreadsheet->getWorksheets();
$worksheet = $worksheetFeed->getByTitle('Sheet 1');
$listFeed = $worksheet->getListFeed();
foreach ($listFeed->getEntries() as $entry) {
    $values = $entry->getValues();
    $array [] = $values;
}