用文本编辑器打开 nm-system-settings.conf

内容如下：

# This file is installed into /etc/NetworkManager, and is loaded by
# NetworkManager by default.  To override, specify: '--config file'
# during NM startup.  This can be done by appending to DAEMON_OPTS in
# the file:
#
# /etc/default/NetworkManager
#

[main]
plugins=ifupdown,keyfile

[ifupdown]
managed=false

将 managed=false 改成 managed=true 保存，退出

使用下面的命令，刷新，让网络连接的图标显示出来：