[Solved] Problem with QML Extension

[Alexander Linne]

Hi!

I'm currently have a problem with using a QML Extension.

I'm working on a project that consists of an QML Application and an QML Extension Plugin. In the Plugin I have (only) C++ classes that should be used in the Application.
Let's say the application's project name is QMLApplication and the library's project name QMLExtension then my folder structure looks like this:
@
D:\Projects\Qt
|-- QMLApplication
|-- Build
|-- QMLApplication
|-- Desktop_Qt_5_2_0_MSVC2012_32bit
|-- debug
|-- QMLApplication.exe
|-- QMLExtension
|-- Desktop_Qt_5_2_0_MSVC2012_32bit
|-- debug
|-- QMLPlugind.dll
|-- qmldir
|-- QMLApplication
|-- qml
|-- Window
|-- Window.qml
|-- Main.cpp
|-- QtGUI.qrc
|-- QMLApplication.pro
|-- QMLExtension
|-- CppClass.cpp
|-- CppClass.hpp
|-- qmldir
|-- QMLExtensionPlugin.cpp
|-- QMLExtensionPlugin.hpp
@

QMLApplication.pro:
@QT += qml quick

qmlfoler.source = qml
qmlfoler.target = qml
DEPLOYMENTFOLDERS = qmlfoler

Additional import path used to resolve QML modules in Creator's code model

QML_IMPORT_PATH =

Source files.

SOURCES +=
Main.cpp

Target

TARGET = QMLApplication

Resource files.

RESOURCES +=
QtGUI.qrc

Librarys.

win32:CONFIG(release, debug|release):LIBS += -L$$PWD/../Build/QMLExtension/Desktop_Qt_5_2_0_MSVC2012_32bit/release -lQMLExtension
}
else:win32:CONFIG(debug, debug|release):LIBS += -L$$PWD/../Build/QMLExtension/Desktop_Qt_5_2_0_MSVC2012_32bit/debug -lQMLExtensiond
}
#else:unix: LIBS += -L$$PWD/?/ -QMLExtension

Include- and dependpaths.

INCLUDEPATH += $$PWD/../QMLExtension
DEPENDPATH += $$PWD/../QMLExtension

OTHER_FILES +=
qml/Window/Window.qml
@
Main.cpp:
@#include <QtGui/QGuiApplication>
#include <QtQml>

#include <CppClass.hpp>

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

QByteArray data = "1";
qputenv("QML_IMPORT_TRACE", data);

QQmlApplicationEngine engine;
engine.load(QUrl("qrc:/qml/Window/Window.qml"));

return app.exec();

}@

QMLExtension.pro:
@TEMPLATE = lib
TARGET = QMLExtension
QT -= gui
QT += qml
CONFIG += qt plugin

TARGET = $$qtLibraryTarget($$TARGET)
uri = QMLExtension

DEFINES += QMLEXTENSION_LIBRARY

SOURCES += CppClass.cpp
QMLExtensionPlugin.cpp

HEADERS += CppClass.hpp
QMLExtensionPlugin.hpp

OTHER_FILES +=
qmldir

!equals(PRO_FILE_PWD, $$OUT_PWD) {
copy_qmldir.target = $$OUT_PWD/qmldir
copy_qmldir.depends = $$PRO_FILE_PWD/qmldir
copy_qmldir.commands = $(COPY_FILE) "$$replace(copy_qmldir.depends, /, $$QMAKE_DIR_SEP)" "$$replace(copy_qmldir.target, /, $$QMAKE_DIR_SEP)"
QMAKE_EXTRA_TARGETS += copy_qmldir
PRE_TARGETDEPS += $$copy_qmldir.target
}

qmldir.files = qmldir
unix {
installPath = $$[QT_INSTALL_QML]/$$replace(uri, \., /)
qmldir.path = $$installPath
target.path = $$installPath
INSTALLS += target qmldir
}
@

CppClass.hpp:
@#ifndef QMLEXTENSION_CPPCLASS_HPP
#define QMLEXTENSION_CPPCLASS_HPP

#include <QtCore/QObject>

#include "QMLExtension_Global.h"

namespace QMLExtension{

class QMLEXTENSIONSHARED_EXPORT CppClass: public QObject {
Q_OBJECT

Q_DISABLE_COPY(CppClass)

public:
CppClass(QObject *parent = 0);
~CppClass();

// Some more functions...

};

bool operator==(const CppClass &lclass, const CppClass &rclass);

} // namespace QMLExtension

#endif // QMLEXTENSION_CPPCLASS_HPP
@

QMLExtensionPlugin.hpp:
@#ifndef QMLEXTENSIONPLUGIN_HPP
#define QMLEXTENSIONPLUGIN_HPP

#include <QtQml/QQmlExtensionPlugin>

class QMLExtensionPlugin : public QQmlExtensionPlugin
{
Q_OBJECT
Q_PLUGIN_METADATA(IID "org.qt-project.Qt.QQmlExtensionInterface")

public:
void registerTypes(const char *uri);
};

#endif // QMLEXTENSIONPLUGIN_HPP
@

QMLExtensionPlugin.cpp:
@#include <qqml.h>

#include "QMLExtensionPlugin.hpp"

#include "CppClass.hpp"

void QMLExtensionPlugin::registerTypes(const char *uri)
{
qmlRegisterTypeQMLExtension::CppClass(uri, 1, 0, "CppClass");
}
@

And finally the qmldir-file:
@module QMLExtension
plugin QMLExtension
classname QMLExtensionPlugin
@

In Window.qml i then want to import it like this:
@import QMLExtension 1.0@

When I now build everything and run the Application i get:
@QQmlApplicationEngine failed to load component
qrc:/qml/Window/Window.qml:5 module "QMLExtension" is not installed@

This happens if i set my QML2_IMPORT_PATH to D:\Projects\Qt\QMLApplication\Build\QMLExtension\Desktop_Qt_5_2_0_MSVC2012_32bit\

If I set it to D:\Projects\Qt\QMLApplication\ I get the following output:
@QQmlImports(qrc:/qml/Window/Window.qml)::addLibraryImport: "QMLExtension" 1.0 as ""
QQmlImports(qrc:/qml/Window/Window.qml)::importExtension: loaded "D:/Projects/Qt/QMLApplication/QMLExtension/qmldir"
QQmlImportDatabase::resolvePlugin: Could not resolve plugin "QMLExtension" in "D:/Projects/Qt/QMLApplication/QMLExtension"
QQmlApplicationEngine failed to load component
qrc:/qml/Window/Window.qml:5 module "QMLExtension" plugin "QMLExtension" not found@

So this time the qmldir file located in my project directory is recognized. Here I already wonder why the one in the Build directory was not recognized.
If I would now copy the .dll from the build directory in the project diretory it start correctly.

So can anybody explain why it only works the second way?
Also if I copy the qmldir and .dll files directly to the executable it does not start...
At least I don't want to copy the .dll for every start of the application...

Regards