QT 5.3.2 QCoreApplication::postEvent: Unexpected null receiver- Conflicting properties 'visible' and 'visibility' error



  • Upon running my QT application, I am seeing this Unexpected null receiver error. What is this error?

    QCoreApplication::postEvent: Unexpected null receiver
    file:///home/andy/Qt/5.3/gcc_64/qml/QtQuick/Controls/ApplicationWindow.qml: Conflicting properties 'visible' and 'visibility' for Window 'root'

    The error also mentions something about conflicting 'visible' and 'visibility' properties in ApplicationWindow.qml



  • I wanted to copy the contents of qquickwindowmodule.cpp (located in /home/andy/Qt/5.3/Src/qtdeclarative/src/quick/items/qquickwindowmodule.cpp) which contains the error message. I can't figure out why is the error message popping up when I run the application.
    ....
    /****************************************************
    ** $QT_END_LICENSE$
    **
    ****************************************************************************/

    #include "qquickwindowmodule_p.h"
    #include "qquickscreen_p.h"
    #include "qquickview_p.h"
    #include <QtQuick/QQuickWindow>
    #include <QtCore/QCoreApplication>
    #include <QtQml/QQmlEngine>

    #include <private/qguiapplication_p.h>
    #include <private/qqmlengine_p.h>
    #include <qpa/qplatformintegration.h>

    QT_BEGIN_NAMESPACE

    class QQuickWindowQmlImpl : public QQuickWindow, public QQmlParserStatus
    {
    Q_INTERFACES(QQmlParserStatus)
    Q_OBJECT

    Q_PROPERTY(bool visible READ isVisible WRITE setVisible NOTIFY visibleChanged)
    Q_PROPERTY(Visibility visibility READ visibility WRITE setVisibility NOTIFY visibilityChanged)
    

    public:
    QQuickWindowQmlImpl(QWindow *parent = 0)
    : QQuickWindow(parent)
    , m_complete(false)
    , m_visible(isVisible())
    , m_visibility(AutomaticVisibility)
    {
    connect(this, &QWindow::visibleChanged, this, &QQuickWindowQmlImpl::visibleChanged);
    connect(this, &QWindow::visibilityChanged, this, &QQuickWindowQmlImpl::visibilityChanged);
    }

    void setVisible(bool visible) {
        if (!m_complete)
            m_visible = visible;
        else if (!transientParent() || transientParent()->isVisible())
            QQuickWindow::setVisible(visible);
    }
    
    void setVisibility(Visibility visibility)
    {
        if (!m_complete)
            m_visibility = visibility;
        else
            QQuickWindow::setVisibility(visibility);
    }
    

    Q_SIGNALS:
    void visibleChanged(bool arg);
    void visibilityChanged(QWindow::Visibility visibility);

    protected:
    void classBegin() {
    QQmlEngine* e = qmlEngine(this);
    //Give QQuickView behavior when created from QML with QQmlApplicationEngine
    if (QCoreApplication::instance()->property("__qml_using_qqmlapplicationengine") == QVariant(true)) {
    if (e && !e->incubationController())
    e->setIncubationController(incubationController());
    }
    Q_ASSERT(e);
    {
    QV4::ExecutionEngine *v4 = QQmlEnginePrivate::getV4Engine(e);
    QV4::Scope scope(v4);
    QV4::ScopedObject v(scope, new (v4->memoryManager) QQuickRootItemMarker(e, this));
    rootItemMarker = v;
    }
    }

    void componentComplete() {
        m_complete = true;
        if (transientParent() && !transientParent()->isVisible()) {
            connect(transientParent(), &QQuickWindow::visibleChanged, this,
                    &QQuickWindowQmlImpl::setWindowVisibility, Qt::QueuedConnection);
        } else {
            setWindowVisibility();
        }
    }
    

    private Q_SLOTS:
    void setWindowVisibility()
    {
    if (transientParent() && !transientParent()->isVisible())
    return;

        if (sender()) {
            disconnect(transientParent(), &QWindow::visibleChanged, this,
                       &QQuickWindowQmlImpl::setWindowVisibility);
        }
    
        // We have deferred window creation until we have the full picture of what
        // the user wanted in terms of window state, geometry, visibility, etc.
    
        if ((m_visibility == Hidden && m_visible) || (m_visibility > AutomaticVisibility && !m_visible)) {
            QQmlData *data = QQmlData::get(this);
            Q_ASSERT(data && data->context);
    
            QQmlError error;
            error.setObject(this);
    
            const QQmlContextData* urlContext = data->context;
            while (urlContext && urlContext->url.isEmpty())
                urlContext = urlContext->parent;
            error.setUrl(urlContext ? urlContext->url : QUrl());
    
            QString objectId = data->context->findObjectId(this);
            if (!objectId.isEmpty())
                error.setDescription(QCoreApplication::translate("QQuickWindowQmlImpl",
                    "Conflicting properties 'visible' and 'visibility' for Window '%1'").arg(objectId));
            else
                error.setDescription(QCoreApplication::translate("QQuickWindowQmlImpl",
                    "Conflicting properties 'visible' and 'visibility'"));
    
            QQmlEnginePrivate::get(data->context->engine)->warning(error);
        }
    
        if (m_visibility == AutomaticVisibility) {
            setWindowState(QGuiApplicationPrivate::platformIntegration()->defaultWindowState(flags()));
            setVisible(m_visible);
        } else {
            setVisibility(m_visibility);
        }
    }
    

    private:
    bool m_complete;
    bool m_visible;
    Visibility m_visibility;
    QV4::PersistentValue rootItemMarker;
    };

    void QQuickWindowModule::defineModule()
    {
    const char uri[] = "QtQuick.Window";

    qmlRegisterType<QQuickWindow>(uri, 2, 0, "Window");
    qmlRegisterRevision<QWindow,1>(uri, 2, 1);
    qmlRegisterRevision<QWindow,2>(uri, 2, 2);
    qmlRegisterRevision<QQuickWindow,1>(uri, 2, 1);//Type moved to a subclass, but also has new members
    qmlRegisterRevision<QQuickWindow,2>(uri, 2, 2);
    qmlRegisterType<QQuickWindowQmlImpl>(uri, 2, 1, "Window");
    qmlRegisterUncreatableType<QQuickScreen>(uri, 2, 0, "Screen", QStringLiteral("Screen can only be used via the attached property."));
    

    }

    #include "qquickwindowmodule.moc"

    QT_END_NAMESPACE

    %%%%%%%%%%%%%%%%%55


Log in to reply
 

Looks like your connection to Qt Forum was lost, please wait while we try to reconnect.