QML and Qt Quick

Replying to share my personal experience with this issue. Changing the ownership of the instantiated object to "QQmlEngine::CppOwnership":http://doc.qt.io/qt-5/qqmlengine.html#ObjectOwnership-enum before returning it indeed fixes the issue. What is not very intuitive though is the fact that you have to change the ownership to CppOwnership even if the objectOwnership() method already returns CppOwnership. This gives something like: @QObject * MyClass::InvokableMethod ( ... ) { QObject * pObject = InstanciateObject( ... ); QQmlEngine::ObjectOwnership ow = engine->objectOwnership( pObject ); // Here, ow == QQmlEngine::CppOwnership engine->setObjectOwnership( pObject, QQmlEngine::CppOwnership ); return pObject; }@ The "setObjectOwnership()":http://doc.qt.io/qt-5/qqmlengine.html#setObjectOwnership and "objectOwnership()":http://doc.qt.io/qt-5/qqmlengine.html#objectOwnership methods seem to perform more stuff than just set and get a two-value property on the object, something that does not appear in the documentation. Anyway, thanks for the post.

Try changing to... @Window { id: root width: 200 height: 200@ or maybe set/use the minimum/maximum width and height properties IDK but I think if you don't set the properties, they may default to 0

[quote author="ondrejandrej" date="1421762292"]Can I avoid copying those files e. g. by adding them to resources?[/quote]Interesting idea; I've never tried putting official files in a resource before. You could try it, but I'm not sure if the LGPL license allows that. If you have the "Professional license":http://www.qt.io/download/ you could use the Qt Quick Compiler to convert your QML source code into your program binaries.

Hi, QDeclarativeView is for Qt Quick 1. These are old technologies which are now deprecated. Use QQuickWidget + Qt Quick 2 instead. See "Porting QML Applications to Qt 5":http://doc.qt.io/qt-5/qtquick-porting-qt5.html for more info.

Hi, I don't know why, but the Qt engineers do. You can find them at the "Interest mailing list":http://lists.qt-project.org/mailman/listinfo/interest (You need to subscribe first)

yes, install apt-get install xserver-xorg-video-intel libgl1-mesa-glx libgl1-mesa-dri xserver-xorg-core [quote author="sierdzio" date="1421827439"]Do you have OpenGL drivers installed?[/quote]

Once again I shoot myself in the foot. I'm posting this for the benefit of everyone else since it was such a stupid thing that I did: qRegisterMetaType<QObject*>("QQuickitemLayer"); What's going on here (as far as I can tell) is that QObject* was bound to the name QQuickItemLayer in the Qt Meta Object system. The issue with this is that the subsequent QML elements are registered also using these same types. I know this is a vague explanation- but it boils down to the meta type system. Taking this line out in my code fixed the issue I was seeing. I'm writing a blogpost elsewhere to fully explain some of the things I tried since a lot of it is off topic. The reason I put this line of code in was that the QmlEngine was reporting that this was an issue in a console app. I thought I was being clever by providing this type (it silenced the console errors). However, it just caused a bigger issue.

Hi, You can add Item to ApplicationWindow and then use Keys.onBackPressed in it. Keep focus on this Item.

Hi, For that kind of questions you shoud rather go to the interest mailing list. You'll find there Qt's developers/maintainers (this forum is more user oriented) the #qt IRC channel can also be a good place to discuss this

I glad to help you with your problem. If your problem was fix please mark thread as SOLVED.

Right :) Still adhered to the old style ;)

You're Welcome :) Happy Coding..

Hi, what exactly went wrong ? I used C++ QCamera(and all related) from QML and everything is working properly, but I didn't try to find camera object from qml root. Instead I create a property in C++ class, expose it to qml, and from qml assign the camera object to that C++ property.

bq. Is it possible to create a property alias for “label”? I guess it won't work as the Component which it refers to would not have been initiated. If your purpose is to dynamically change the label's component you can create a property Component and the assign it a Component when you call it. eg: @ MyButton.qml Item { property Component myComp Button { style: ButtonStyle { id: styleLabel label: myComp background: Rectangle { ... } } } } Main.qml MyButton { myComp: Qt.createComponent("labelDelegate1.qml") } MyButton { myComp: Qt.createComponent("labelDelegate2.qml") } @ Hope this helps...

For every animation you need to tell which which property you would like animate. If you want the animation to triggered by default, you can Behaviour on <x> {} e.g @Rectangle { id: rect width: 100; height: 100 color: "red" Behavior on x { NumberAnimation { duration: 1000 } } MouseArea { anchors.fill: parent onClicked: rect.width = 50 } }@

Did you get a chance to look at how to integrate C++ and QML ? QtAssistant provides good examples for this integration. You will be able to solve your issue.

Thanks ustulation. I tryied running QJSEngine::collectGarbage() and it didn't release memory. Any ideas ?

Hi, Start by reading "this thread":http://qt-project.org/forums/viewthread/49581 Use QQuickWidget if (and only if) you want to integrate your QML GUI into a C++ QWidget-based GUI. Post back if you'd like anything clarified. [quote author="ustulation" date="1421583894"]For eg., In my QQuickView derivative I could easily handle the events by overriding the appropriate virtuals. Don't know if that would be possible/convenient for QQmlApplicationEngine approach, etc.[/quote]What kind of events do you mean?

It looks like GridView not intended to display items with different size (width/height).