[SOLVED] How to use multiple different list element in ListView



  • I can use different properties in ListElement when using QML model. The following code works properly. Arg2 is only in the first ListElement:

    ListView  {
        id:listView
        height: 200
        Layout.fillWidth: true
        delegate: Rectangle {
            height: 50
            Label {
                anchors.fill: parent
                text: arg1 + " " + (arg2 === undefined ? "" : " " + arg2)
            }
        }
        model: ListModel {
            ListElement { arg1: "Elem1"; arg2: "Elem1arg2" }
            ListElement { arg1: "Elem2" }
        }
    }
    

    But I'd like to load model from C++. I have multiple inherited classes.

    Here is base idea of my classes:

    class Class1 : public QObject
    {
      Q_PROPERTY(QString arg1...
    //...
    class Class2 : public Class1
      Q_PROPERTY(QStirng arg2...
    

    I tried to use QObjectList -based model. I didn't get it working because only properties from Class1 are available:

    QList<QObject*> list;
    list.append(new Class1("Elem1"));
    list.append(new Class2("Elem2","Elem2arg1" ));
    return QVariant::fromValue(list);
    

    How I can get properties from both classes? Or is it even possible?


  • Moderators

    @jimcad AFAIK it should work. All the parent's properties should be visible to child.
    Have you set the inherited property's value from child ?



  • @p3c0 Yes, arg1 is set for both and it's visible in QML. But arg2 is available only in Class2 and it's not visible in QML. That is the problem.


  • Moderators

    @jimcad OfCourse how would arg2 be available to Class1 ? Children inherit properties of their parents and not the other way.
    You can add a check there something like:

    Text {
        text : typeof model.modelData.arg2==="undefined" ? "DefaultValue" : model.modelData.arg2
    }
    


  • @p3c0 Yes, I know that. There must be something wrong in my code because this not working either:

        MyClass1{ id: class1 }
        MyClass2{ id: class2 }
    
        Component.onCompleted: {
            class2.arg1 = "Changed arg1"
            console.log(class2.arg1) // works ok
            class2.arg2 = "Changed arg2" // <-- Doesn't work        
            console.log(class2.arg2)
        }
    

    Seems that all properties from inherited classes doesn't works. Here is my example project: https://www.dropbox.com/s/mi33b8ml8nctrup/qml-test.zip?dl=0



  • @p3c0 I found it. It was missing Q_OBJECT macro in Class2. Now it works properly. Thanks for your advice.


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