How to run a newly created rqt plugin?

edit

You need to put a phyton script like the following into your package rqt_mypkg and name it after the package rqt_mypkg:

#!/usr/bin/env python

import sys

from rqt_gui.main import Main

main = Main()
sys.exit(main.main(sys.argv, standalone='rqt_mypkg'))

Now you can run you rosrun rqt_mypkg rqt_mypkg in oder for starting your plugin stand-alone, i. e. independent from rqt_gui; otherwise, you may want to load your plugin into rqt_gui....

Note, that the script file also needs to be executable; Maybe you need to run chmod +x rqt_mypkg in the folder where you have placed the rqt_mypkg script file. E. g. for an error msg like:

Couldn't find executable named rqt_mypkg below /home/alan/catkin_ws/src/rqt_mypkg
Found the following, but they're either not files, or not executables:
 /home/alan/catkin_ws/src/rqt_mypkg
 /home/alan/catkin_ws/src/rqt_mypkg/src/rqt_mypkg

go into the folder where the python script is placed in:

cd /home/alan/catkin_ws/src/rqt_mypkg/src/

and run there:

chmod +x rqt_mypkg