problem with QWebView::show()

[januszmk]

Hi.
I have class inherited from QThread. I am using QWebPage in there, for my developers purpose, I getting QWebPage from QWebView, but when I am calling function QWebView::show(), my program is terminated with error:

[xcb] Unknown request in queue while dequeuing
[xcb] Most likely this is a multi-threaded client and XInitThreads has not been called
[xcb] Aborting, sorry about that.
N: /var/tmp/portage/x11-libs/libX11-1.5.0/work/libX11-1.5.0/src/xcb_io.c:178: dequeue_pending_request: Warunek zapewnienia `!xcb_xlib_unknown_req_in_deq' nie został spełniony.
The program has unexpectedly finished.

[xcb] Unknown request in queue while dequeuing
[xcb] Most likely this is a multi-threaded client and XInitThreads has not been called
[xcb] Aborting, sorry about that.
N: /var/tmp/portage/x11-libs/libX11-1.5.0/work/libX11-1.5.0/src/xcb_io.c:178: dequeue_pending_request: Warunek zapewnienia `!xcb_xlib_unknown_req_in_deq' nie został spełniony.
The program has unexpectedly finished.

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My header file:

...
#include <QThread>
#include <QtWebKit>
 
class myclass : public QThread
{
....
    Q_OBJECT
public:
    explicit myclass();
...
protected:
    Logger *logger;
    QEventLoop loop;
    Settings *mySettings;
 
public slots:
    void pageLoading() { loop.exec(); }
}

...
#include <QThread>
#include <QtWebKit>

class myclass : public QThread
{
....
    Q_OBJECT
public:
    explicit myclass();
...
protected:
    Logger *logger;
    QEventLoop loop;
    Settings *mySettings;

public slots:
    void pageLoading() { loop.exec(); }
}

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source file:

myclass::myclass()
{
    logger = Logger::getInstance();
    mySettings = Settings::getInstance();
    QWebView *view = new QWebView();
    logger->Info("Showing QWebView");
    view->show();
    myPage = view->page();
 
    connect(myPage->networkAccessManager(), SIGNAL(finished(QNetworkReply*)), &loop, SLOT(quit()));
    connect(myPage,SIGNAL(loadStarted()), this, SLOT(pageLoading()));
}

myclass::myclass()
{
    logger = Logger::getInstance();
    mySettings = Settings::getInstance();
    QWebView *view = new QWebView();
    logger->Info("Showing QWebView");
    view->show();
    myPage = view->page();

    connect(myPage->networkAccessManager(), SIGNAL(finished(QNetworkReply*)), &loop, SLOT(quit()));
    connect(myPage,SIGNAL(loadStarted()), this, SLOT(pageLoading()));
}

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I deleted line with view->show(); and my program is working fine.
My class has type of abstract. I inherit her in dynamic library. Am I doing something wrong, or it's problem with libX11?

[ChrisW67]

QWebView is a GUI component and should only be used from the GUI (main) thread.
You almost certainly don't need a thread here anyway.

[januszmk]

I know that, I am creating QWebView and showing in main thread (it's in the constructor, not in run() function), and it's crashing anyway when I'm calling QWebView::show().
I need threads for other things.

Edit:
I changed public QThread to public QObject and it's still crashing with this same error

[wysota]

Which version of Qt are you using? Could you prepare a minimal compilable example reproducing your problem?

[januszmk]

ok, sorry, I am doing this in another thread, but it's not this object, just object in 2 levels up.
so problem solved. thanks