我遇到了同样的问题，并且我正在使用Ubuntu 15.10.

I had the same problem and I'm using Ubuntu 15.10.

就我而言，为了解决此问题，我使用Synaptic软件包管理器(其中包括SimpleXml)安装了php7.0-xml软件包.因此，重新启动我的Apache服务器后，我的问题解决了.这个软件包是Debian版本的，您可以在这里找到: https://packages.debian .org/sid/php7.0-xml .

In my case, to solve this issue, I installed the package php7.0-xml using the Synaptic package manager, which include SimpleXml. So, after restart my Apache server, my problem was solved. This package came in the Debian version and you can find it here: https://packages.debian.org/sid/php7.0-xml.