[SOLVED]Cannot call c++ function from qml

khajvah

@QGuiApplication app(argc, argv);

QQmlEngine engine;


QQmlContext* maincontext = new QQmlContext(engine.rootContext());

MainWindowMC mainMC(maincontext);

QQmlComponent component(&engine, QUrl::fromLocalFile&#40;"qml/convQML/main.qml"&#41;&#41;;


QQuickWindow* window =  qobject_cast<QQuickWindow*> (component.create(maincontext&#41;);
window->show();

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

This is my main.cpp.

I pass pointer of context to MainWindowMC.
Here is MainWindowMC:
@MainWindowMC::MainWindowMC(QQmlContext* maincontext)
:MainM()
{

typeGenerator();

maincontext->setContextProperty("mainwin", this);

maincontext->setContextProperty("typemodel", QVariant::fromValue(m_typemodel));

maincontext->setContextProperty("unitmodel", QVariant::fromValue(m_unitmodel));

}@

and the class declaration:
@public:

MainWindowMC(QQmlContext*);

QStringList typemodel();

void typeGenerator();

Q_INVOKABLE void unitGenerator(QString type);

@

It seems I have done everything - registered object in context, made Q_INVOKABLE function-but I cannot call the funtion from QML. It throws "TypeError: Object [object Object] has no method 'unitGenerator'"
What am I doing wrong?

Optionaly, this is how I try to use the function in QML:

@ onCurrentTextChanged: mainwin.unitGenerator(typebox.currentText)
@

sierdzio

Wow, this is really strange way of instantiating QML engine and view. Why are you doing this in such a complicated manner?

Is your MainWindowMC a QObject? Have you added the Q_OBJECT macro?

khajvah

bq. Wow, this is really strange way of instantiating QML engine and view. Why are you doing this in such a complicated manner?Is your MainWindowMC a QObject? Have you added the Q_OBJECT macro?

MainWindowMC is dreived from a class which on the other hand derives from QObject. I had a an issue with Q_OBJECT. The thing is mainM has Q_OBJECT macro (base class of MainWindowMC). -When I add Q_OBJECT in MainWindowMC, it throws some strange errors but I think Q_OBJECT moves to MainWindowMC ad it is derived from mainM- I have added Q_OBJECT macro but still the same problem.

Which part is complicated? I have just started using QML, so I don't know much about it. I think everything is as it should be. I make engine, give the pointer of context to a class(I don't want to make my main.cpp too long) and I create component with that context?

Qnoobish

I think first you have to load the QML file, then try to get the rootContext and set the property to use your class object with invokable functions.

@
QQmlEngine engine;
QQmlComponent component(&engine, QUrl::fromLocalFile("qml/convQML/main.qml"));

QQmlContext* maincontext = new QQmlContext(engine.rootContext());

MainWindowMC mainMC(maincontext);
@

sierdzio

Well for me the easy way is this, but everybody has their own:
@
// from memory, sorry for any errors
QQuickView *view = new QQuickView();

MainWindowMC *mainMC = new MainWindowMC();
view->rootContext()->setCOntextProperty("myMain", mainMC);

view->setSource(QUrl::fromUserInput("myQml.qml"));
view->show();
return app.exec();
@

khajvah

Anyways ppl, sorry for wasting your time, it is not my fault. I cleaned and rebuilt and it started working (probably some pre-compilation issues)