arm - Qt 应用程序尝试加载平台插件 "xcb"而不是 "eglfs"

Question

已建 树莓派 2 linux 发行版，包括 Qt5.4 + QtWebKit + QML 插件，使用 Yocto on fido分公司See tutorial

使用以下 QML 脚本进行测试

root@raspberrypi2:~# more webkit3.qml 
import QtQuick 2.0
import QtQuick.Controls 1.0
import QtWebKit 3.0

ScrollView {
    width: 640
    height: 480
    WebView {
        id: webview
        url: "http://qt-project.org"
        anchors.fill: parent
        onNavigationRequested: {
            // detect URL scheme prefix, most likely an external link
            var schemaRE = /^\w+:/;
            if (schemaRE.test(request.url)) {
                request.action = WebView.AcceptRequest;
            } else {
                request.action = WebView.IgnoreRequest;
                // delegate request.url here
            }
        }
    }
}

错误信息

This application failed to start because it could not find or load the Qt platform plugin "xcb"

看来还是尝试从 XCB plugin开始这与 X11 有关，而我指定了 EGLFS (？？)

root@raspberrypi2:~# /usr/bin/qt5/qmlscene  webkit3.qml -platform eglfs
Unable to query physical screen size, defaulting to 100 dpi.
To override, set QT_QPA_EGLFS_PHYSICAL_WIDTH and QT_QPA_EGLFS_PHYSICAL_HEIGHT (in millimeters).
This application failed to start because it could not find or load the Qt platform plugin "xcb".

Available platform plugins are: eglfs, linuxfb, minimal, minimalegl, offscreen.

Reinstalling the application may fix this problem.

任何想法为什么我会遇到这个问题？

已安装 QT5 插件平台

root@raspberrypi2:/usr/lib/qt5/plugins/platforms# ls -al
drwxr-xr-x    2 root     root          4096 Jun 12 12:59 .
drwxr-xr-x   18 root     root          4096 Jun 12 13:03 ..
-rwxr-xr-x    1 root     root        601864 Jun 11 15:19 libqeglfs.so
-rwxr-xr-x    1 root     root        499564 Jun 11 15:19 libqlinuxfb.so
-rwxr-xr-x    1 root     root         20576 Jun 11 15:19 libqminimal.so
-rwxr-xr-x    1 root     root        478500 Jun 11 15:19 libqminimalegl.so
-rwxr-xr-x    1 root     root        465740 Jun 11 15:19 libqoffscreen.so

请不要向我推荐 this或 this问题。消息是相同的，但我不认为这是相同的原因。

Answer 1

也许 qmlscene正在吃参数——通过 -platform qml 文件名之前的选项，或设置 QT_QPA_PLATFORM环境变量到 eglfs而不是命令行参数。

为了将来，您可能想要制作 eglfs使用 -qpa eglfs 配置 Qt 的默认选择.