入门操作：
左侧边栏目没了：https://blog.csdn.net/weixin_44511670/article/details/144979040
qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.是需要～/.bashrc改成如下形式：
bash
#Qt5
export QtDir='/home/david/MySoft/Qt5.15/5.15.0/gcc_64'
export PATH=${QtDir}/bin:${PATH}
export LD_LIBRARY_PATH=${QtDir}/lib:${LD_LIBRARY_PATH}
export QT_PLUGIN_PATH=${QtDir}/plugins:${QT_PLUGIN_PATH}
export QML2_IMPORT_PATH=${QtDir}/qml:${QML2_IMPORT_PATH}
export QT_QPA_PLATFORM_PLUGIN_PATH=${QtDir}/plugins/platforms:${QT_QPA_PLATFORM_PLUGIN_PATH}
export DISPLAY=:1尤其增加：export DISPLAY=:1 24.0