QML and Qt Quick

Thanks, @SGaist . It turns out that it was sufficient to recreate the engine. I modified the relevant portion of my code as follows: QQmlApplicationEngine *engine; qmlRegisterType<MyClass>("MyClass", 1, 0, "MyClass"); do { engine = new QQmlApplicationEngine; engine->rootContext()->setContextProperty("myClass", &myClass); engine->loadFromModule("restartQml", "Main"); currentExitCode = app.exec(); delete engine; } while (currentExitCode == MyClass::EXIT_CODE_REBOOT); return currentExitCode; } And it seems to work fine. I also discovered that I didn't need to pass in the QGuiApplication to my handler class; evidently this is provided to me via qApp: #include <qguiapplication.h> void MyClass::restartRequested() { qApp->exit( EXIT_CODE_REBOOT ); } Thank you for the help.

The solution without the aliases, or Items, is definitely cleaner and more memory efficient. Unfortunately, Creator can't understand the syntax and provide autocomplete on the properties within the nestings! Using the Item / alias pattern resolves that.

hi thank u for reply @SGaist yes i have checked the file is present and also check the QtLocationPlugin.pri file for SOURCES += $$PWD/QGCMapEngine.cpp is present i just don't know what build flag is missing

@GrecKo Thank you ! Indeed I can use that property :)

This might be a bug or "feature" of this component, then. You can file a report about it on Qt bug tracker.

@SimonLiu Two options: Use an earlier version Build PySide6 yourself

I ran into this issue myself when using QQuickWidget (since you're certainly going to want to be communicating between C++ and Qt Quick in that case). The original comment about setInitialProperties really triggered me, since that means there wasn't parity between QQuickWidget and QQuickView in a way that doesn't make sense. The same was true of the more modern loadFromModule pattern. So I created a couple patches to at least to try and rectify this in 6.9: https://codereview.qt-project.org/c/qt/qtdeclarative/+/586483/2 https://codereview.qt-project.org/c/qt/qtdeclarative/+/586520/1 But also I my case, that doesn't help me "today". I agree that using a QML Singleton is the correct solution over setting a context property, but that still led me to the issue that I wanted to do that the Modern/Correct way, but I didn't really understand from the docs how to get access to that Singleton from the C++ side. I found that this was the correct documentation page that explained that: https://doc.qt.io/qt-6/qtqml-cppintegration-exposecppstate.html But basically this is what the C++ code would look like: Singleton *singleton = engine->singletonInstance<Singleton *>("MyModule", "Singleton"); singleton->setThing(77);

Debugging with RenderDoc, I found that the problem may occur in the "draw" function of the "QRhiCommandBuffer" class. In the original code, I called the "draw" function twice, namely: cb->draw(6, 1, 0, 0); cb->draw(3, 1, 6, 1); I intend to specify the "instanceCount", and the most important parameter - "firstInstance" (the "firstInstance" in the first call is 0, and 1 in the second) for each rendering. Through RenderDoc's debugging (as shown in the figure below), I found that these two calls correspond to two "glDrawArray" function events. The vertex number counts are 6 and 3, respectively, consistent with the numbers in my code, but "glDrawArrays" cannot specify instance ID. [image: 3fdfccc2-f30e-450e-afaf-6b203ac745a3.png] Furthermore, I changed the two "draw" function calls to one but changed the "instanceCount" to 2(draw two rectangle instances), and the firstInstance started from 0: cb->draw(6, 2, 0, 0); This time, the "draw" function corresponds to a "glDrawArraysInstanced" function event in RenderDoc, and the two graphics can use different object matrices. [image: c8968a62-361d-40e6-be47-8ef57cd6b8bb.png] Two rectangle instances with different model matrixes [image: e48dd912-2538-4e31-89eb-313b306e5601.png] So, It seems that when you want to draw multiple instances using the draw function, the parameter "firstInstance" should start from 0; the draw function can work adequately; is this a feature or a bug on the Windows platform? I noticed the note "firstInstance may not be supported when QRhi::BaseInstance feature is reported as not supported..." but I have checked the "QRhi::BaseInstance" feature in my platform, and it's said supported.

Further investigation on this. Some how we need to load the staticlibrary. On Linux 6.4.3 Q_INIT_RESOURCE(MyLib). This automatically loaded the libary & called qml_register type. Windows 6.61 - Q_INIT_RESOURCE(MyLib) - This gave me linker error saying that qInitResource_MyLib() is not defined. I just created the object from C++ class present in the library. It worked. We don't have to modify with extern "C". Not required.

This will be fixed in the upcoming Qt 6.8 release, and is back-ported to 6.7.2. See https://bugreports.qt.io/browse/QTBUG-125006, which adds a check for the QT_FFMPEG_PROTOCOL_WHITELIST environment variable, which the user can set to override the whitelist with their own.

@Shankarlinga-M thank you i solve that

@Anumas Thanks for the answer! Added subfolder to INCLUDEPATH is help to me.

Thanks for sharing! It’s actually a bug, which the workaround clearly demonstrates.

Why are you closing the view, then? I don't think you need to. Instead of closing it, replace the current item in the StackView (like you do in stackView.push(Qt.resolvedUrl("qrc:/qml/MainRootWindow.qml"))) . So remove this screen.visible=false By default, StackView implements different transition for different events like popEnter, pushExit, ect. Here's an example of how to implement your own transitions: https://doc.qt.io/qt-6/qtquickcontrols-customize.html#customizing-stackview

@GrecKo Thank you I will try.

I found solution without creating resource. The pro file must by eddited like this with example in my example with Kafelek.qml After space write filename with extension in resource.files :) QT += quick SOURCES += \ main.cpp resources.files = main.qml Kafelek.qml resources.prefix = /$${TARGET} RESOURCES += resources # Additional import path used to resolve QML modules in Qt Creator's code model QML_IMPORT_PATH = # Additional import path used to resolve QML modules just for Qt Quick Designer QML_DESIGNER_IMPORT_PATH = # Default rules for deployment. qnx: target.path = /tmp/$${TARGET}/bin else: unix:!android: target.path = /opt/$${TARGET}/bin !isEmpty(target.path): INSTALLS += target DISTFILES += \ Kafelek.qml \ images/logo.png

Yes, that works. Thank you!