致命错误：在原则中对null调用成员函数getId（）

Question

我说错了，

Fatal error: Call to a member function getId() on null.

但是我如何检查元素，这是我的代码

$infoArray['groupId'] = $info->getId();
$infoArray['name'] = $info->getName();
$infoArray['addressLine1'] = $info->getAddressLine1();
$infoArray['addressLine2'] = $info->getAddressLine2();
$infoArray['isActive'] = $info->getActive();
$infoArray['countryId'] = $info->getCountry()->getId(); //Here is my error line
$infoArray['countryName'] = $info->getCountry()->getName();
$infoArray['stateId'] = $info->getState()->getId();
$infoArray['stateName'] = $info->getState()->getName();
$infoArray['cityId'] = $info->getCity()->getId();
$infoArray['cityName'] = $info->getCity()->getName();
$infoArray['areaId'] = $info->getArea()->getId();
$infoArray['areaName'] = $info->getArea()->getName();
$infoArray['zipcode'] = $info->getZipcode();

Answer 1

将行替换为：

$infoArray['countryId'] = $info->getCountry() ? $info->getCountry()->getId() : null;

对与关联相对应的每一行执行相同操作（可以为null），null如果对象为null ，则将返回该行。