ubuntu下面板上无网络连接的图标

解决方法：删除旧的网络配置，重新让networkManager自动配置

sudo service network-manager stop
sudo rm /var/lib/NetworkManager/NetworkManager.state
sudo service network-manager start
 
sudo gedit /etc/NetworkManager/nm-system-settings.conf
false----改成--->true
 
sudo service network-manager restart