Qt xcb插件错误？这些技巧帮你搞定！

Qt xcb插件错误？这些技巧帮你搞定！

引用

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6

来源

1.

https://blog.csdn.net/LOVEmy134611/article/details/107212845

2.

https://blog.csdn.net/lnstop/article/details/139748905

3.

https://forum.qt.io/topic/66774/unable-to-link-qt-application-statically

4.

https://forum.qt.io/topic/149680/could-not-load-the-qt-platform-plugin-xcb

5.

https://neucrack.com/p/407

6.

https://forum.qt.io/topic/143750/qt-qpa-plugin-could-not-find-the-qt-platform-plugin-xcb-in

在使用Qt开发跨平台应用程序时，你可能会遇到一个令人头疼的问题：xcb插件加载失败。这个错误不仅会影响程序的正常运行，还可能让你在开发过程中陷入困境。本文将为你详细介绍这个错误的产生原因，并提供多种实用的解决方案。

当你尝试运行一个Qt应用程序时，如果看到以下错误信息，那么很可能就是遇到了xcb插件问题：

qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.
This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.

这个错误通常发生在Linux系统上，特别是在使用X Window System（X11）作为显示系统的环境中。xcb是X Window System的C语言绑定，而Qt使用xcb插件来与X11进行交互。因此，当Qt无法加载xcb插件时，应用程序就无法正常显示图形界面。

大多数情况下，这个错误是由于缺少必要的库文件引起的。你可以尝试以下命令来安装所有与xcb相关的库：

sudo apt install libxcb-*

这个命令会安装一系列的xcb相关库，包括libxcb-xinerama0，这个库在很多情况下是解决问题的关键。

如果上述方法未能解决问题，你可以通过设置环境变量来获取更多的调试信息。在终端中输入以下命令：

export QT_DEBUG_PLUGINS=1

然后重新运行你的应用程序。这次你会看到更详细的错误日志，其中可能包含类似以下的信息：

QFactoryLoader::QFactoryLoader() looking at "/home/brainiac/Qt/Tools/QtCreator/lib/Qt/plugins/platforms/libqxcb.so"
Found metadata in lib /home/brainiac/Qt/Tools/QtCreator/lib/Qt/plugins/platforms/libqxcb.so, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "xcb"
        ]
    },
    "archreq": 0,
    "className": "QXcbIntegrationPlugin",
    "debug": false,
    "version": 331520
}
Got keys from plugin meta data ("xcb")
QFactoryLoader::QFactoryLoader() looking at "/home/brainiac/Qt/Tools/QtCreator/lib/Qt/plugins/platforms/libqlinuxfb.so"
Found metadata in lib /home/brainiac/Qt/Tools/QtCreator/lib/Qt/plugins/platforms/libqlinuxfb.so, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "linuxfb"
        ]
    },
    "archreq": 0,
    "className": "QLinuxFbIntegrationPlugin",
    "debug": false,
    "version": 331520
}
Got keys from plugin meta data ("linuxfb")
QFactoryLoader::QFactoryLoader() looking at "/home/brainiac/Qt/Tools/QtCreator/lib/Qt/plugins/platforms/libqminimal.so"
Found metadata in lib /home/brainiac/Qt/Tools/QtCreator/lib/Qt/plugins/platforms/libqminimal.so, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "minimal"
        ]
    },
    "archreq": 0,
    "className": "QMinimalIntegrationPlugin",
    "debug": false,
    "version": 331520
}
Got keys from plugin meta data ("minimal")
QFactoryLoader::QFactoryLoader() looking at "/home/brainiac/Qt/Tools/QtCreator/lib/Qt/plugins/platforms/libqoffscreen.so"
Found metadata in lib /home/brainiac/Qt/Tools/QtCreator/lib/Qt/plugins/platforms/libqoffscreen.so, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "offscreen"
        ]
    },
    "archreq": 0,
    "className": "QOffscreenIntegrationPlugin",
    "debug": false,
    "version": 331520
}
Got keys from plugin meta data ("offscreen")
QFactoryLoader::QFactoryLoader() looking at "/home/brainiac/Qt/Tools/QtCreator/lib/Qt/plugins/platforms/libqvnc.so"
Found metadata in lib /home/brainiac/Qt/Tools/QtCreator/lib/Qt/plugins/platforms/libqvnc.so, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "vnc"
        ]
    },
    "archreq": 0,
    "className": "QVncIntegrationPlugin",
    "debug": false,
    "version": 331520
}
Got keys from plugin meta data ("vnc")
loaded library "/home/brainiac/Qt/Tools/QtCreator/lib/Qt/plugins/platforms/libqxcb.so"
QXcbIntegrationPlugin::create() called
QXcbIntegration: Cannot create platform OpenGL context, neither GLX nor EGL available
Failed to create OpenGL context for format QSurfaceFormat(version 3.2, options QFlags<QSurfaceFormat::FormatOption>(DefaultFormatOptions), depthBufferSize 24, redBufferSize -1, greenBufferSize -1, blueBufferSize -1, alphaBufferSize -1, stencilBufferSize 8, samples -1, swapBehavior QSurfaceFormat::DoubleBuffer, swapInterval 1, colorSpace QSurfaceFormat::DefaultColorSpace, profile  QSurfaceFormat::NoProfile)
Could not initialize OpenGL for Qt
Could not initialize EGL for Qt
Could not initialize OpenGL for Qt
Could not initialize EGL for Qt
qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.
This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.
Available platform plugins are: eglfs, linuxfb, minimal, minimalegl, offscreen, vnc, xcb.

从日志中可以看出，虽然libqxcb.so被找到了，但在加载时却因为缺少libxcb-xinerama.so.0库而失败。这时，你只需要安装这个缺失的库：

sudo apt-get install libxcb-xinerama0

安装完成后，再次运行ldd libqxcb.so，确认所有依赖库都已正确链接，然后重新启动你的应用程序。

如果上述方法都无法解决问题，你可以尝试使用其他平台插件。Qt提供了多种平台插件，包括offscreen、wayland等。你可以通过设置QT_QPA_PLATFORM环境变量来切换插件：

export QT_QPA_PLATFORM=offscreen
# 或者
export QT_QPA_PLATFORM=wayland

需要注意的是，使用offscreen插件时，你的应用程序将不会显示任何图形界面，这通常用于服务器端或无头（headless）环境。而wayland插件则适用于使用Wayland显示服务器的系统。

在Ubuntu 18.04系统上，一位开发者遇到了同样的问题。他首先尝试了基础解决方案，即安装所有xcb相关库，但问题仍未解决。于是，他采用了高级排查方法，通过设置QT_DEBUG_PLUGINS=1获取了详细的错误日志。日志显示，虽然libqxcb.so被找到了，但在加载时却因为缺少libxcb-xinerama.so.0库而失败。最终，通过安装libxcb-xinerama0库，问题得到了解决。

通过以上步骤，大多数情况下可以解决 "Plugin class name could not be determined for plugin 'xcb'" 的问题。如果仍无法解决，请提供更多日志信息以便进一步排查。