1、在ROS官网找到rqt_virtual_joy/plugin.xml,复制文件内容
<library path="src">
<class name="My Plugin" type="rqt_virtual_joy.virtual_joy_module.MyPlugin" base_class_type="rqt_gui_py::Plugin">
<description>
An example Python GUI plugin to create a great user interface.
</description>
<qtgui>
<group>
<label>Robot Tools</label>
</group>
<!-- <group>
<label>Subgroup</label>
</group> -->
<label>Virtual Joystick</label>
<icon type="file">resource/input-gaming.png</icon>
<statustip>Great user interface to provide real value.</statustip>
</qtgui>
</class>
</library>
2.打开报错中指出的文件缺失的目录/opt/ros/melodic/share/rqt_virtual_joy/,新建文件plugin.xml
3.打开plugin.xml,粘贴第一步复制的代码,保存退出即可。
参考;https://answers.ros.org/question/354039/rqt_virtual_joypluginxml-file-is-missing/