QJSEngine add custom object

[TheHawk]

Hi,

I am trying to use a script to plot a graph in my program.
I am using QCustomPlot and it works fine if used in my C++ code.
However, if I pass the QCustomPlot to the QJSEngine like this:

QJSEngine myEngine;
QCustomPlot *graph = new QCustomPlot;
QJSValue scriptgraph = myEngine.newQObject(graph);
myEngine.globalObject().setProperty("graph",scriptgraph);

And my script looking like this:

graph.addGraph();
graph.xAxis.setLabel("TESTX");
graph.yAxis.setLabel("TESTY");
graph.replot();

The QJSEngine will throw the following error:
result: 1 : "ReferenceError: addGraph is not defined"

Which makes me think that the object is passes but not the classes it has. Am I missing something here?

Thanks!

[t3685]

@TheHawk

Hi,

You need to show your QCustomPlot class. Did you add the Q_INVOKABLE macro in front of your addGraph() function?

Greetings,

t3685

[TheHawk]

@t3685

The QCustomPlot is from internet. And no, I did not add Q_Invokable to the functions of QCustomPlot. I can try and see if this fixes the error. Thanks!

Edit: tried Q_INVOKABLE QCPGraph *addGraph(QCPAxis *keyAxis=0, QCPAxis *valueAxis=0); without succes.

[t3685]

@TheHawk

Hi,

What error are you getting? Did you rerun qmake to regenerate the moc_*.cpp files?

Greetings,

t3685

[TheHawk]

@t3685
Hi,

I am getting: result: 1 : "ReferenceError: addGraph is not defined" with my script looking like:

	graph.addGraph();
	graph.xAxis.setLabel("TESTX");
	graph.yAxis.setLabel("TESTY");
	graph.replot();

and wrapping the graph like this:

    QCustomPlot *graph = new QCustomPlot;
    ui->verticalLayout->addWidget(graph);
    QJSValue scriptgraph = myEngine.newQObject(graph);
    myEngine.globalObject().setProperty("graph",scriptgraph);

And yes, I cleaned, reran Qmake and even rebuild everything but without succes.

Am I running into a limitation of QJSEngine? If so, what would be the wisest thing for me to do? I would really like to access objects like the above, if that is not possible, would QTQuick with QML be anything for me? If I read this it looks like that what I am trying to achieve is relatively simple in QML with QtQuick. However, I do not have QtQuick installed at the moment so I would have to rewrite all my existing code to use the import "script.js" as scipt function, correct? If not, how would this be done in my Qt Creator project?

Thanks! :)

[t3685]

@TheHawk

Hi,

How are you invoking your script? As in how are you calling "script.js". Are you calling it using "myEngine"? If yes, can you show that code?

Greetings,

t3685

[TheHawk]

@t3685
Hi,

I am calling it like this:

    QString fileName = "customlogic.qs";
    QFile scriptFile(fileName);
    if (!scriptFile.open(QIODevice::ReadOnly))
    {
    }// handle error

    QTextStream stream(&scriptFile);
    QString contents = stream.readAll();
    scriptFile.close();
    QJSValue result = myEngine.evaluate(contents, fileName);
    if (result.isError())
    {
        qDebug() << "result: " << result.property("lineNumber").toInt() << ":" << result.toString();
    }

thanks!

[t3685]

@TheHawk

Have you tried giving argument to addGraph()? I don't remember whether the default argument translate well to javascript. If that still doesn't work, you can try to make add a dummy QObject class with Q_INVOKABLE functions to your engine to see if the problem is in your code or some possible interaction with QCustomPlot