在DateTime::diff上出现致命错误

Question

我在这里问，我知道还有其他问题和答案，我一直在通过它们:在PHP中计算两个日期之间的小时数

但是我仍然找不到解决问题的方法。情况是这样的:我使用谷歌日历Api。我有一个foreach()循环在运行，它画出事件的dateTime()。我想要得到开始和结束时间的差值。我的代码如下:

$neweventDateStr = new DateTime($event->start->dateTime);
$neweventDateEnd = new DateTime($event->end->dateTime);
$diff = $eventDateEnd->diff($neweventDateStr);

然而，我在最后一行得到以下错误:

Fatal error: Call to a member function diff() on string

我已经检查过了，两个变量都被识别为dateTime对象。因此，我不知道为什么给我上面列出的错误。知道为什么会这样吗?

注意，代码:

$event->start->dateTime 

以dateTime RFC 3339格式从google服务器返回日期和时间的值:https://developers.google.com/google-apps/calendar/v3/reference/events

返回如下值:

$event->start->dateTime = 2015-07-06T14:30:00+02:00 
$event->se->dateTime = 2015-07-06T15:30:00+02:00

I have try to:

echo $neweventDateStr;

and i返回错误(如预期的那样)，该变量无法转换为字符串，因为它是dateTime对象格式。

Answer 1

问题出在你的代码中:-

     $diff = $eventDateEnd->diff($neweventDateStr);

应该是:-

$diff = $neweventDateEnd->diff($neweventDateStr); // because no where $eventDateEnd is defined.

示例如下:—

<?php
 $neweventDateStr = new DateTime('2015-04-04 10:10:10');
 $neweventDateEnd = new DateTime('2015-04-10 10:10:10');
 $diff = $neweventDateEnd->diff($neweventDateStr); // instead of $eventDateEnd i write $neweventDateEnd
 print_r($diff);
 ?>

输出:https://eval.in/393320