Error: plugin cannot be loaded for module "QtQuick".

[user_mail07]

Hi,

I am running my app with open source Qt 5.1.1 using QtQuick2ApplicationViewer on Windows 7. Application builds fine whenever i try to run I get plugin cannot be loaded for module "QtQuick".I feel there is something wrong with qmlRegisterType.

main.qml

import QtQuick 2.0
 
Item {
    width: 800
    height: 600
 
    Row {
        id: layoutRow
 
        TextButton {
            text: "1x1"
            onClicked: { workspaceWidget.setLayout(WorkspaceWidget.Layout_1x1) }
        }
 
        TextButton {
            text: "2x2"
            onClicked: { workspaceWidget.setLayout(WorkspaceWidget.Layout_2x2) }
        }
 
    }
 
}

import QtQuick 2.0

Item {
    width: 800
    height: 600

    Row {
        id: layoutRow

        TextButton {
            text: "1x1"
            onClicked: { workspaceWidget.setLayout(WorkspaceWidget.Layout_1x1) }
        }

        TextButton {
            text: "2x2"
            onClicked: { workspaceWidget.setLayout(WorkspaceWidget.Layout_2x2) }
        }

    }

}

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main.cpp

#include <QtGui/QGuiApplication>
#include "qtquick2applicationviewer.h"
#include <QQmlContext>
#include <QtQml>
#include "WorkspaceWidget.h"
 
int main(int argc, char *argv[])
{
    QGuiApplication app(argc, argv);
    QtQuick2ApplicationViewer viewer;
 
    WorkspaceWidget workspacePane;
    viewer.rootContext()->setContextProperty(QLatin1String("workspaceWidget"), &workspacePane);
    viewer.setResizeMode(QQuickView::SizeRootObjectToView);
 
    qmlRegisterType<WorkspaceWidget>("QtQuick", 2, 0, "WorkspaceWidget");
 
    viewer.setMainQmlFile(QStringLiteral("qml/QtQuick2Demo/main.qml"));
    viewer.showExpanded();
    return app.exec();
}

#include <QtGui/QGuiApplication>
#include "qtquick2applicationviewer.h"
#include <QQmlContext>
#include <QtQml>
#include "WorkspaceWidget.h"

int main(int argc, char *argv[])
{
    QGuiApplication app(argc, argv);
    QtQuick2ApplicationViewer viewer;

    WorkspaceWidget workspacePane;
    viewer.rootContext()->setContextProperty(QLatin1String("workspaceWidget"), &workspacePane);
    viewer.setResizeMode(QQuickView::SizeRootObjectToView);

    qmlRegisterType<WorkspaceWidget>("QtQuick", 2, 0, "WorkspaceWidget");

    viewer.setMainQmlFile(QStringLiteral("qml/QtQuick2Demo/main.qml"));
    viewer.showExpanded();
    return app.exec();
}

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I am getting following error in debug pane in Qt Creator

file:///C:/Projects/build-QtQuick2Demo-Desktop_Qt_5_1_1_MSVC2010_32bit-Debug/qml/QtQuick2Demo/main.qml:1:1: plugin cannot be loaded for module "QtQuick": Namespace 'QtQuick' has already been used for type registration 
     import QtQuick 2.0 
     ^

file:///C:/Projects/build-QtQuick2Demo-Desktop_Qt_5_1_1_MSVC2010_32bit-Debug/qml/QtQuick2Demo/main.qml:1:1: plugin cannot be loaded for module "QtQuick": Namespace 'QtQuick' has already been used for type registration 
     import QtQuick 2.0 
     ^

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[bounce]

it tells you exactly the problem, QtQuick is already taken

qmlRegisterType<WorkspaceWidget>("user_mail07", 2, 0, "WorkspaceWidget");

[motaito]

You don't really provide a lot of information. Based on what's there the answer has been given already. Generally you need these steps:

1. Create c++ class that contains the Q_OBJECT macro

class WorkspaceWidget
{
	Q_OBJECT
public:
	// your implementatin goes here...
	// whatever function you want to call from qml must be made invokable with the proper macro declaration
	Q_INVOKABLE void foo();
}

class WorkspaceWidget
{
	Q_OBJECT
public:
	// your implementatin goes here...
	// whatever function you want to call from qml must be made invokable with the proper macro declaration
	Q_INVOKABLE void foo();
}

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2. Register the class in main.cpp

qmlRegisterType<WorkspaceWidget>("WorkspaceWidgetNameSpace", 2, 0, "WorkspaceWidgetQml");
 
// WorkspaceWidget: Your class
// WorkspaceWidgetNameSpace: a namespace that has not yet been used. Can be anything, but must be unique
// WorkspaceWidgetQml: Some name that you give to handle it in a qml file. Can be anything, but must be unique

qmlRegisterType<WorkspaceWidget>("WorkspaceWidgetNameSpace", 2, 0, "WorkspaceWidgetQml");

// WorkspaceWidget: Your class
// WorkspaceWidgetNameSpace: a namespace that has not yet been used. Can be anything, but must be unique
// WorkspaceWidgetQml: Some name that you give to handle it in a qml file. Can be anything, but must be unique

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3. in some qml-file

// import your name space with major and minor version
import WorkspaceWidgetNameSpace 2.0
 
 
// declare your class, as qml is a declarative environment
WorkspaceWidgetQml {
	id: workspaceWidgetID
}
 
// do with it what you want
TextButton {
	text: "1x1"
	onClicked: { workspaceWidgetID.setLayout(WorkspaceWidget.Layout_1x1); }
}

// import your name space with major and minor version
import WorkspaceWidgetNameSpace 2.0


// declare your class, as qml is a declarative environment
WorkspaceWidgetQml {
	id: workspaceWidgetID
}

// do with it what you want
TextButton {
	text: "1x1"
	onClicked: { workspaceWidgetID.setLayout(WorkspaceWidget.Layout_1x1); }
}

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