[rospack] Error: package ‘learning_communication‘ not found

出现问题：

[rospack] Error: package 'learning_communication' not found

yf@yf:~/Alltest/catkin_ws/src$ rosrun learning_communication talker
[rospack] Error: package 'learning_communication' not found

在最后运行时，出现error: package ‘***’ not found错误

       解决方法：source devel/setup.bash