populate() not working Repeater

Tobias83

Hallo Everybody,

I want to visualize a hard sphere simulation. There for I work with Singleton and QAbstractListmodel. I got the spheres to be be drawn in a window, but I can't move them per mouseclick. The mouseclick is recognized by the QAbstractListmodel, but the populate() function does not give the new coordinates of the spheres and ellipses to the QML. The spheres and ellipses are drwan by a Repeater and DelegateChooser. The DelagateChooser must be, because I also want to draw squares later. How can I get the populate function to work?

This is my main function:

int main(int argc, char *argv[])
{
    tw_hardcoresystem::Hardcore_InitClass initClass(argc, argv);
    tw_hardcoresystem::System system;
    initClass.return_Hardcoresystem_single(&system);

    QGuiApplication app(argc, argv);

    tw_hardcoresystem::Hardcore_Entrymodel entryModel;
    entryModel.setSystem(&system);
    
    qmlRegisterSingletonInstance("hardcoresystem", 1, 0, "Hardcoreentrymodel", &entryModel);

    QQmlApplicationEngine engine;
    engine.load(QUrl(QStringLiteral("qrc:/qt/qml/Main.qml")));

    return app.exec();
}

And my QML file looks like this:

import QtQuick 2.12
import QtQuick.Window 2.12
import QtQuick.Controls 2.12
import QtQuick.Shapes 1.7
//import QtQuick.Layouts 2.2
import QtQml.Models 2.12
import Qt.labs.qmlmodels 1.0

import hardcoresystem 1.0

Window {
    id: appwindow
    visible: true
    width: Hardcoreentrymodel.returnWindowLx()
    height: Hardcoreentrymodel.returnWindowLy()
    color: "grey"

    Rectangle{
        id: hardcoresystemrectangle
        anchors.left: appwindow.left
        anchors.top: appwindow.top
        width: appwindow.width
        height: appwindow.height
        color: appwindow.color
        MouseArea {
            anchors.fill: parent
            onClicked: Hardcoreentrymodel.doNewStep()
        }
    }
    Connections{
        id: hardcoreentrymodel
        target: Hardcoreentrymodel
        function onNewStepDoing(){console.log("New Path doing ...\n")}
        function onNewStepReady(){console.log("New Path ready ...\n")}
        function onDataChanged(){console.log("DataChanged received")}
    }

    Item{
        id: partilcesitem
        width: hardcoresystemrectangle.width
        height: hardcoresystemrectangle.height
        anchors.left: hardcoresystemrectangle.left
        anchors.top: hardcoresystemrectangle.top
        Repeater {
            id: partilcesreapeter
            model: Hardcoreentrymodel
            delegate: chooser
            DelegateChooser{
                id: chooser
                role: "type"
                DelegateChoice{
                    roleValue: "sphere";
                    delegate: Item{
                        id: sphereimage
                        width: 2.0*Number(model.semimajoraxis)
                        height: 2.0*Number(model.semiminoraxis)
                        x: Number(model.xcoord - model.semimajoraxis)
                        y: Number(model.ycoord - model.semiminoraxis)
                        Canvas {
                            anchors.fill: parent
                            onPaint: {
                                var ctx = getContext('2d');
                                ctx.beginPath();
                                ctx.lineWidth = 1
                                ctx.strokeStyle = "black"
                                ctx.fillStyle = model.color
                                ctx.ellipse(x,y,width,height)
                                ctx.stroke();
                                ctx.fill();
                            }
                        }
                        rotation: Number(model.angle)
                        Component.onCompleted: console.log(model.iparticle,", sphere ",x,", ",y,", ",width,", ",height,", ", model.color)
                    }
                }
                DelegateChoice{
                        roleValue: "ellipse";
                        delegate: Item{
                            id: ellipseimage
                            width: 2.0*Number(model.semimajoraxis)
                            height: 2.0*Number(model.semiminoraxis)
                            x: Number(model.xcoord - model.semimajoraxis)
                            y: Number(model.ycoord - model.semiminoraxis)
                            Canvas {
                                anchors.fill: parent
                                onPaint: {
                                    var ctx = getContext('2d');
                                    ctx.beginPath();
                                    ctx.lineWidth = 1
                                    ctx.strokeStyle = "black"
                                    ctx.fillStyle = model.color
                                    ctx.ellipse(x,y,width,height)
                                    ctx.stroke();
                                    ctx.fill();
                                }
                            }
                            rotation: Number(model.angle)
                            Component.onCompleted: console.log(model.iparticle,", ellipse ",x,", ",y,", ",width,", ",height,", ", model.color)
                        }
                    }
                }
            }
        }
    }
}

Kind regards,
Tobias

MIlan Radosavljevic

According to Repeater Documentation you should use modelData if model is string list or object list. Try something like this.

...
DelegateChooser{
                id: chooser
                role: "type"
                required property string modelData
...
                y: Number(modelData.ycoord - modelData.semiminoraxis)
...

GrecKo

What does your poppulate function do? Is it called by Hardcoreentrymodel.doNewStep()?

Tobias83

@MIlan-Radosavljevic said in populate() not working Repeater:

required property string modelData

Dear Mllan,
this leads to this errors:
qrc:/qt/qml/Main.qml:79:25: TypeError: Cannot read property 'ycoord' of undefined
qrc:/qt/qml/Main.qml:78:25: TypeError: Cannot read property 'xcoord' of undefined
qrc:/qt/qml/Main.qml:77:25: TypeError: Cannot read property 'semiminoraxis' of undefined
qrc:/qt/qml/Main.qml:76:25: TypeError: Cannot read property 'semimajoraxis' of undefined
qml: 0 , sphere 0 , 0 , 0 , 0 , blue

and finally to

QQmlApplicationEngine failed to create component
qrc:/qt/qml/Main.qml:71:17: Required property modelData was not initialized

How can I iniatialize the property modelData?

Tobias

Tobias83

@GrecKo Hello GrecKo,

This is my populate function of Entrymodel. It is called by doNewStep():

void tw_hardcoresystem::Hardcore_Entrymodel::populate()
{
    int ipart;

    for(ipart=0; ipart<nparticles; ipart++){
        mDatas[ipart]= initqtview.SystemToWindow(hardcoresystem->returnIParticle(ipart));
    }

    emit dataChanged(index(0),index(nparticles));
    return;
}

The function should be OK, because the particles are drawn at first.

Tobias

Tobias83

This Weekend I made a linux distribution update with updated Qt library and updated QtCreator. Now I get a new error when building the sources - I had to change the cmake file:

Failed to import hardcoresystem. Are your import paths set up properly? [import]

and

Warnings occurred while importing module "hardcoresystem": [import]

in cmake I have now (Main2.qml is another testing file:

qt_add_qml_module(simHardcoreQt6
    URI qt/qml
    VERSION 1.0
    QML_FILES Main.qml Main2.qml
)

and in the main.cpp it is still:

[...]
   tw_hardcoresystem::Hardcore_Entrymodel entryModel;
    entryModel.setSystem(&system);
    
    qmlRegisterSingletonInstance("hardcoresystem", 1, 0, "Hardcoreentrymodel", &entryModel);

    QQmlApplicationEngine engine;
    engine.load(QUrl(QStringLiteral("qrc:/qt/qml/Main.qml")));

    return app.exec();

Is there a problem where the qml files are situated? The Programm still compiles and the spheres are drawn at the right places at the beginning. Just the emit dataChanged(index(0),index(nparticles)) statement has no effect ...

Tobias

Tobias83

Can this be the error: mabe the model is loaded twice - the first time for the repeater and for drawing the circles, and the second time where the doNewPath() function is acting - so the emit statement in populate() has no effect on drawing the circles?

Tobias83

OK, the model has only one instance - I checked their this pointer. So that the emit dataChanged(index(0),index(nparticles)); will not update the particle coordinates may have another reason.

The model is not loaded well by the qml file. How can I avoid these Unqualified access [unqualified] errors:

Failed to import hardcoresystem. Are your import paths set up properly? [import]

In the cmake file:

qt_add_qml_module(simHardcoreQt6
    URI qt/qml
    VERSION 1.0
    QML_FILES Main.qml Main2.qml
)

In the main.cpp:

  tw_hardcoresystem::Hardcore_Entrymodel entryModel;
    entryModel.setSystem(&system);
    
    qmlRegisterSingletonInstance("hardcoresystem", 1, 0, "Hardcoreentrymodel", &entryModel);

    QQmlApplicationEngine engine;
    engine.load(QUrl(QStringLiteral("qrc:/qt/qml/Main.qml")));

In the qml file:

[...]
import hardcoresystem 1.0
[...]

Tobias83

Hello everybody,

I'm overlucky: I found the error for myself (-:

The correct code line is now:

emit dataChanged(index(0),index(nparticles-1));

instead of

emit dataChanged(index(0),index(nparticles));

Now I can start working!

Thanks to all!

Tobias