PyQt5：解決qt.qpa.plugin: Could not load the Qt platform plugin "xcb"錯誤

在Linux上使用PyQt5時，出現qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.錯誤，通過調試發現是libxcb-xinerama0丟失，安裝libxcb-xinerama0即可解決：

sudo apt install --reinstall libxcb-xinerama0

測試環境：Ubuntu 20.04 + Python 3.8 + PyQt5 5.15.0

下面介紹具體過程和解決辦法。

運行PyQt5程序時，出現如下錯誤：

$ python3 tms.py
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, wayland-egl, wayland, wayland-xcomposite-egl, wayland-xcomposite-glx, webgl, xcb.

發現是Qt加載插件出現問題，通過設置QT_DEBUG_PLUGINS=1，可以查看Qt的插件加載信息。
所以先設置環境變量：

export QT_DEBUG_PLUGINS=1

再次運行程序時，會打印出很多信息，重點是最后一段：

$ python3 tms.py
QFactoryLoader::QFactoryLoader() checking directory path "/home/txfly/PycharmProjects/TMS/venv/lib/python3.8/site-packages/PyQt5/Qt/plugins/platforms" ...
QFactoryLoader::QFactoryLoader() looking at "/home/txfly/PycharmProjects/TMS/venv/lib/python3.8/site-packages/PyQt5/Qt/plugins/platforms/libqeglfs.so"
Found metadata in lib /home/txfly/PycharmProjects/TMS/venv/lib/python3.8/site-packages/PyQt5/Qt/plugins/platforms/libqeglfs.so, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "eglfs"
        ]
    },
    "archreq": 0,
    "className": "QEglFSIntegrationPlugin",
    "debug": false,
    "version": 331520
}


Got keys from plugin meta data ("eglfs")
QFactoryLoader::QFactoryLoader() looking at "/home/txfly/PycharmProjects/TMS/venv/lib/python3.8/site-packages/PyQt5/Qt/plugins/platforms/libqlinuxfb.so"
Found metadata in lib /home/txfly/PycharmProjects/TMS/venv/lib/python3.8/site-packages/PyQt5/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/txfly/PycharmProjects/TMS/venv/lib/python3.8/site-packages/PyQt5/Qt/plugins/platforms/libqminimal.so"
Found metadata in lib /home/txfly/PycharmProjects/TMS/venv/lib/python3.8/site-packages/PyQt5/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/txfly/PycharmProjects/TMS/venv/lib/python3.8/site-packages/PyQt5/Qt/plugins/platforms/libqminimalegl.so"
Found metadata in lib /home/txfly/PycharmProjects/TMS/venv/lib/python3.8/site-packages/PyQt5/Qt/plugins/platforms/libqminimalegl.so, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "minimalegl"
        ]
    },
    "archreq": 0,
    "className": "QMinimalEglIntegrationPlugin",
    "debug": false,
    "version": 331520
}


Got keys from plugin meta data ("minimalegl")
QFactoryLoader::QFactoryLoader() looking at "/home/txfly/PycharmProjects/TMS/venv/lib/python3.8/site-packages/PyQt5/Qt/plugins/platforms/libqoffscreen.so"
Found metadata in lib /home/txfly/PycharmProjects/TMS/venv/lib/python3.8/site-packages/PyQt5/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/txfly/PycharmProjects/TMS/venv/lib/python3.8/site-packages/PyQt5/Qt/plugins/platforms/libqvnc.so"
Found metadata in lib /home/txfly/PycharmProjects/TMS/venv/lib/python3.8/site-packages/PyQt5/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")
QFactoryLoader::QFactoryLoader() looking at "/home/txfly/PycharmProjects/TMS/venv/lib/python3.8/site-packages/PyQt5/Qt/plugins/platforms/libqwayland-egl.so"
Found metadata in lib /home/txfly/PycharmProjects/TMS/venv/lib/python3.8/site-packages/PyQt5/Qt/plugins/platforms/libqwayland-egl.so, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "wayland-egl"
        ]
    },
    "archreq": 0,
    "className": "QWaylandEglPlatformIntegrationPlugin",
    "debug": false,
    "version": 331520
}


Got keys from plugin meta data ("wayland-egl")
QFactoryLoader::QFactoryLoader() looking at "/home/txfly/PycharmProjects/TMS/venv/lib/python3.8/site-packages/PyQt5/Qt/plugins/platforms/libqwayland-generic.so"
Found metadata in lib /home/txfly/PycharmProjects/TMS/venv/lib/python3.8/site-packages/PyQt5/Qt/plugins/platforms/libqwayland-generic.so, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "wayland"
        ]
    },
    "archreq": 0,
    "className": "QWaylandIntegrationPlugin",
    "debug": false,
    "version": 331520
}


Got keys from plugin meta data ("wayland")
QFactoryLoader::QFactoryLoader() looking at "/home/txfly/PycharmProjects/TMS/venv/lib/python3.8/site-packages/PyQt5/Qt/plugins/platforms/libqwayland-xcomposite-egl.so"
Found metadata in lib /home/txfly/PycharmProjects/TMS/venv/lib/python3.8/site-packages/PyQt5/Qt/plugins/platforms/libqwayland-xcomposite-egl.so, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "wayland-xcomposite-egl"
        ]
    },
    "archreq": 0,
    "className": "QWaylandXCompositeEglPlatformIntegrationPlugin",
    "debug": false,
    "version": 331520
}


Got keys from plugin meta data ("wayland-xcomposite-egl")
QFactoryLoader::QFactoryLoader() looking at "/home/txfly/PycharmProjects/TMS/venv/lib/python3.8/site-packages/PyQt5/Qt/plugins/platforms/libqwayland-xcomposite-glx.so"
Found metadata in lib /home/txfly/PycharmProjects/TMS/venv/lib/python3.8/site-packages/PyQt5/Qt/plugins/platforms/libqwayland-xcomposite-glx.so, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "wayland-xcomposite-glx"
        ]
    },
    "archreq": 0,
    "className": "QWaylandXCompositeGlxPlatformIntegrationPlugin",
    "debug": false,
    "version": 331520
}


Got keys from plugin meta data ("wayland-xcomposite-glx")
QFactoryLoader::QFactoryLoader() looking at "/home/txfly/PycharmProjects/TMS/venv/lib/python3.8/site-packages/PyQt5/Qt/plugins/platforms/libqwebgl.so"
Found metadata in lib /home/txfly/PycharmProjects/TMS/venv/lib/python3.8/site-packages/PyQt5/Qt/plugins/platforms/libqwebgl.so, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "webgl"
        ]
    },
    "archreq": 0,
    "className": "QWebGLIntegrationPlugin",
    "debug": false,
    "version": 331520
}


Got keys from plugin meta data ("webgl")
QFactoryLoader::QFactoryLoader() looking at "/home/txfly/PycharmProjects/TMS/venv/lib/python3.8/site-packages/PyQt5/Qt/plugins/platforms/libqxcb.so"
Found metadata in lib /home/txfly/PycharmProjects/TMS/venv/lib/python3.8/site-packages/PyQt5/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() checking directory path "/usr/bin/platforms" ...
Cannot load library /home/txfly/PycharmProjects/TMS/venv/lib/python3.8/site-packages/PyQt5/Qt/plugins/platforms/libqxcb.so: (libxcb-xinerama.so.0: 無法打開共享對象文件: 沒有那個文件或目錄)
QLibraryPrivate::loadPlugin failed on "/home/txfly/PycharmProjects/TMS/venv/lib/python3.8/site-packages/PyQt5/Qt/plugins/platforms/libqxcb.so" : "Cannot load library /home/txfly/PycharmProjects/TMS/venv/lib/python3.8/site-packages/PyQt5/Qt/plugins/platforms/libqxcb.so: (libxcb-xinerama.so.0: 無法打開共享對象文件: 沒有那個文件或目錄)"
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, wayland-egl, wayland, wayland-xcomposite-egl, wayland-xcomposite-glx, webgl, xcb.

已放棄 (核心已轉儲)

這兒單獨看下最后一段：

Got keys from plugin meta data ("xcb")
QFactoryLoader::QFactoryLoader() checking directory path "/usr/bin/platforms" ...
Cannot load library /home/txfly/PycharmProjects/TMS/venv/lib/python3.8/site-packages/PyQt5/Qt/plugins/platforms/libqxcb.so: (libxcb-xinerama.so.0: 無法打開共享對象文件: 沒有那個文件或目錄)
QLibraryPrivate::loadPlugin failed on "/home/txfly/PycharmProjects/TMS/venv/lib/python3.8/site-packages/PyQt5/Qt/plugins/platforms/libqxcb.so" : "Cannot load library /home/txfly/PycharmProjects/TMS/venv/lib/python3.8/site-packages/PyQt5/Qt/plugins/platforms/libqxcb.so: (libxcb-xinerama.so.0: 無法打開共享對象文件: 沒有那個文件或目錄)"
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, wayland-egl, wayland, wayland-xcomposite-egl, wayland-xcomposite-glx, webgl, xcb.

已放棄 (核心已轉儲)

它提示無法加載libqxcb.so，原因是libxcb-xinerama.so.0: 無法打開共享對象文件: 沒有那個文件或目錄，也就是說libxcb-xinerama.so.0共享庫丟失，導致無法加載libqxcb.so。通過ldd指令查看libqxcb.so的動態鏈接庫，可以看到libxcb-xinerama.so.0 => not found，完整信息如下：

$ ldd /home/txfly/PycharmProjects/TMS/venv/lib/python3.8/site-packages/PyQt5/Qt/plugins/platforms/libqxcb.so
linux-vdso.so.1 (0x00007fff3e530000)
libQt5XcbQpa.so.5 => /home/txfly/PycharmProjects/TMS/venv/lib/python3.8/site-packages/PyQt5/Qt/plugins/platforms/../../lib/libQt5XcbQpa.so.5 (0x00007f6b24dc9000)
libfontconfig.so.1 => /lib/x86_64-linux-gnu/libfontconfig.so.1 (0x00007f6b24d6f000)
libfreetype.so.6 => /lib/x86_64-linux-gnu/libfreetype.so.6 (0x00007f6b24cb0000)
libz.so.1 => /lib/x86_64-linux-gnu/libz.so.1 (0x00007f6b24c94000)
libQt5Gui.so.5 => /home/txfly/PycharmProjects/TMS/venv/lib/python3.8/site-packages/PyQt5/Qt/plugins/platforms/../../lib/libQt5Gui.so.5 (0x00007f6b24360000)
libQt5DBus.so.5 => /home/txfly/PycharmProjects/TMS/venv/lib/python3.8/site-packages/PyQt5/Qt/plugins/platforms/../../lib/libQt5DBus.so.5 (0x00007f6b240d2000)
libQt5Core.so.5 => /home/txfly/PycharmProjects/TMS/venv/lib/python3.8/site-packages/PyQt5/Qt/plugins/platforms/../../lib/libQt5Core.so.5 (0x00007f6b238df000)
libGL.so.1 => /lib/x86_64-linux-gnu/libGL.so.1 (0x00007f6b23857000)
libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007f6b23834000)
libX11-xcb.so.1 => /lib/x86_64-linux-gnu/libX11-xcb.so.1 (0x00007f6b2382f000)
libxcb-icccm.so.4 => /lib/x86_64-linux-gnu/libxcb-icccm.so.4 (0x00007f6b23828000)
libxcb-image.so.0 => /lib/x86_64-linux-gnu/libxcb-image.so.0 (0x00007f6b23621000)
libxcb-shm.so.0 => /lib/x86_64-linux-gnu/libxcb-shm.so.0 (0x00007f6b2361c000)
libxcb-keysyms.so.1 => /lib/x86_64-linux-gnu/libxcb-keysyms.so.1 (0x00007f6b23617000)
libxcb-randr.so.0 => /lib/x86_64-linux-gnu/libxcb-randr.so.0 (0x00007f6b23604000)
libxcb-render-util.so.0 => /lib/x86_64-linux-gnu/libxcb-render-util.so.0 (0x00007f6b235fd000)
libxcb-render.so.0 => /lib/x86_64-linux-gnu/libxcb-render.so.0 (0x00007f6b235ee000)
libxcb-shape.so.0 => /lib/x86_64-linux-gnu/libxcb-shape.so.0 (0x00007f6b235e7000)
libxcb-sync.so.1 => /lib/x86_64-linux-gnu/libxcb-sync.so.1 (0x00007f6b235dd000)
libxcb-xfixes.so.0 => /lib/x86_64-linux-gnu/libxcb-xfixes.so.0 (0x00007f6b235d3000)
libxcb-xinerama.so.0 => not found
libxcb-xkb.so.1 => /lib/x86_64-linux-gnu/libxcb-xkb.so.1 (0x00007f6b235b5000)
libxcb.so.1 => /lib/x86_64-linux-gnu/libxcb.so.1 (0x00007f6b2358b000)
libXext.so.6 => /lib/x86_64-linux-gnu/libXext.so.6 (0x00007f6b23574000)
libX11.so.6 => /lib/x86_64-linux-gnu/libX11.so.6 (0x00007f6b23437000)
libxkbcommon-x11.so.0 => /lib/x86_64-linux-gnu/libxkbcommon-x11.so.0 (0x00007f6b2342c000)
libxkbcommon.so.0 => /lib/x86_64-linux-gnu/libxkbcommon.so.0 (0x00007f6b233ea000)
libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007f6b233e4000)
libstdc++.so.6 => /lib/x86_64-linux-gnu/libstdc++.so.6 (0x00007f6b23203000)
libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007f6b230b2000)
libgcc_s.so.1 => /lib/x86_64-linux-gnu/libgcc_s.so.1 (0x00007f6b23097000)
libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f6b22ea5000)
libxcb-xinerama.so.0 => not found
libgthread-2.0.so.0 => /lib/x86_64-linux-gnu/libgthread-2.0.so.0 (0x00007f6b22ea0000)
libglib-2.0.so.0 => /lib/x86_64-linux-gnu/libglib-2.0.so.0 (0x00007f6b22d77000)
libexpat.so.1 => /lib/x86_64-linux-gnu/libexpat.so.1 (0x00007f6b22d47000)
libuuid.so.1 => /lib/x86_64-linux-gnu/libuuid.so.1 (0x00007f6b22d3e000)
libpng16.so.16 => /lib/x86_64-linux-gnu/libpng16.so.16 (0x00007f6b22d06000)
libdbus-1.so.3 => /lib/x86_64-linux-gnu/libdbus-1.so.3 (0x00007f6b22cb5000)
libicui18n.so.56 => /home/txfly/PycharmProjects/TMS/venv/lib/python3.8/site-packages/PyQt5/Qt/plugins/platforms/../../lib/libicui18n.so.56 (0x00007f6b2281c000)
libicuuc.so.56 => /home/txfly/PycharmProjects/TMS/venv/lib/python3.8/site-packages/PyQt5/Qt/plugins/platforms/../../lib/libicuuc.so.56 (0x00007f6b22462000)
libicudata.so.56 => /home/txfly/PycharmProjects/TMS/venv/lib/python3.8/site-packages/PyQt5/Qt/plugins/platforms/../../lib/libicudata.so.56 (0x00007f6b20a7f000)
/lib64/ld-linux-x86-64.so.2 (0x00007f6b25326000)
libGLdispatch.so.0 => /lib/x86_64-linux-gnu/libGLdispatch.so.0 (0x00007f6b209c7000)
libGLX.so.0 => /lib/x86_64-linux-gnu/libGLX.so.0 (0x00007f6b20993000)
libxcb-util.so.1 => /lib/x86_64-linux-gnu/libxcb-util.so.1 (0x00007f6b2078d000)
libXau.so.6 => /lib/x86_64-linux-gnu/libXau.so.6 (0x00007f6b20785000)
libXdmcp.so.6 => /lib/x86_64-linux-gnu/libXdmcp.so.6 (0x00007f6b2077d000)
libpcre.so.3 => /lib/x86_64-linux-gnu/libpcre.so.3 (0x00007f6b2070a000)
libsystemd.so.0 => /lib/x86_64-linux-gnu/libsystemd.so.0 (0x00007f6b2065d000)
libbsd.so.0 => /lib/x86_64-linux-gnu/libbsd.so.0 (0x00007f6b20643000)
librt.so.1 => /lib/x86_64-linux-gnu/librt.so.1 (0x00007f6b20636000)
liblzma.so.5 => /lib/x86_64-linux-gnu/liblzma.so.5 (0x00007f6b2060f000)
liblz4.so.1 => /lib/x86_64-linux-gnu/liblz4.so.1 (0x00007f6b205ee000)
libgcrypt.so.20 => /lib/x86_64-linux-gnu/libgcrypt.so.20 (0x00007f6b204d0000)
libgpg-error.so.0 => /lib/x86_64-linux-gnu/libgpg-error.so.0 (0x00007f6b204ad000)

解決辦法

通過重新安裝libxcb-xinerama0即可：

sudo apt install --reinstall libxcb-xinerama0

如果是其它共享庫not found，安裝對應的軟件包即可。

版權聲明：本文為「txfly」的原創文章，遵循 CC 4.0 BY-SA 版權協議，轉載請附上原文出處鏈接及本聲明。
原文鏈接：http://www.lxweimin.com/p/b51008566134

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