Load QML Plugins through QDeclarativeEngine

aliander

Hi there!

I currently try to get the QWidgets (in the CppExtensions-Examples) running.

Having the standard example code and trying to load the qml through QDeclarativeEngine gives me the error, that MyPushButton is not a type.

What am I missing?

As those plugins are intended to dynamically extend QML, I'm pretty sure, that I don't have to register the type in my core-application (just providing a kind of self-written qmlviewer). Later on the core-application should do some system related stuff aswell, so using the qmlviewer itself won't help :(

Thanks in advance!
Ali

bunjee

What is MyPushButton ?

aliander

MyPushButton is just a simple QPushButton wich should be provided to qml with a plugin
It is implemented in the examples (declarative/cppextensions/qwidgets)

Here you go: "Link":http://doc.troll.no/master-snapshot/declarative-cppextensions-qwidgets.html

For this discussion I have chosen a provided example on purpose - so we have the same discussion base ;)

bunjee

Do you have this in your cpp:
@qmlRegisterType<MyPushButton>(uri, 1, 0, "MyPushButton");@

And this in your qml:
@import "QWidgets" 1.0@

Does the qwidgets example works for you ?

aliander

Having
@import "QWidgets" 1.0@
in my test qml File (qwidgets.qml)

I don't intend to register the MyPushButton Type in my cpp core-application. The qmlRegisterType should be done through the QWidgetsPlugin (derived from QDeclarativeExtensionPlugin).

I use the example as it is - absolutely no modification. (qwidgets.pro/.qml/.cpp and qmldir used from example)

The point is, that I can't use the qmlviewer to load it, but have to use my own application using a QDeclarativeEngine

The Code is kinda straight forward:

@#include <QtDeclarative>

#include <QCoreApplication>

#include <QDeclarativeEngine>

#include <QDeclarativeContext>

#include <QDeclarativeComponent>

#include <QDebug>

int main(int argc, char *argv[])

{

QCoreApplication app(argc, argv);

QDeclarativeEngine engine;

QDeclarativeContext *context = new QDeclarativeContext(engine.rootContext());

QDeclarativeComponent component(&engine, "qwidgets.qml");

QObject *window = component.create(context);

qDebug() << component.errors();

return app.exec&#40;&#41;;

}@

As I understand QML plugins are supposed to work that way... else ... well, that would be pretty sad ;)

bunjee

Well I guess he is not loading your plugin.

In your code. Can you try putting a qDebug before:

@qmlRegisterType<MyPushButton>(uri, 1, 0, "MyPushButton");@

aliander

Currently doing a fresh rebuild now...

Surprisingly I get a new error msg now

@QWidget: Cannot create a QWidget when no GUI is being used@

So hooray, the plugin-loading seems not to be the problem...for the moment ;)