Please ask about problems and questions regarding this tutorial on answers.ros.org. Don't forget to include in your question the link to this page, the versions of your OS & ROS, and also add appropriate tags.

Create rqt plugin using an existing Qt based tool

This page is under development. Meanwhile, there is a hint.

Motivation

There might be cases where you want to mix ROS and other robotics framework (for various reasons; eg. incorporating legacy codes that use another framework and also use ROS for new features) where the "other" part doesn't want to depend on ROS. rqt does a good job too in this situation.