Why is this 'keyValueList.push(KeyValue{})' code syntax incorrect in qml?

mirro

What is the code to properly initialize QVariantList?

qmlRegisterType<KeyValue>("customqml", 1, 0, "KeyValue");
}

import QtQuick 2.7
import customqml 1.0

Item{
 property var keyValueList[]
Component.onCompleted:{
     keyValueList.push(KeyValue{})
}

ODБOï

@mirro said in Why is this 'keyValueList.push(KeyValue{})' code syntax incorrect in qml?:

push(KeyValue{})

you can not create your qml object like that, see Dynamic QML Object Creation

Window {
    id: root
    visible: true
    width: 640
    height: 480

    property var keyValueList : []

    onKeyValueListChanged:{
        for(var i=0;i<keyValueList.length;i++){
            console.log(keyValueList[i].color)

            //js kay-value
            //console.log(keyValueList[i].key)
        }
    }


    Component.onCompleted: {
        var tmp = [] // temporary list needed, can't  keyValueList.push() directly
        for(var i=0;i<10;i++){
            var newObject = Qt.createQmlObject('import QtQuick 2.15; Rectangle {color: "red";}',root); // Put your Type instead of rectangle
            tmp.push(newObject)
        }
        keyValueList = tmp 
    }

    // js kay-value
    //    Component.onCompleted:{
    //        var tmp = []
    //        for(var i=0;i<10;i++){
    //            tmp.push({key : Math.random()})
    //        }
    //        keyValueList = tmp
    //    }
}

mirro

@LeLev Thank you. I just tested your method successfully
But I don't understand why you can't just assign values but use temporary variables instead?
Also, do I need to free memory in this 'Component.onDestruction'?

Component.onCompleted: {
        var tmp = [] 
        for(var i=0;i<10;i++){
            var newObject = Qt.createQmlObject('import customqml 1.0;KeyValue{id:key}',root)
            tmp.push(newObject)
        }
        keyValueList = tmp 
    }

ODБOï

@mirro said in Why is this 'keyValueList.push(KeyValue{})' code syntax incorrect in qml?:

But I don't understand why you can't just assign values but use temporary variables instead?

you can, but be aware of
https://doc.qt.io/qt-5/qml-variant.html#storing-arrays-and-objects

Additionally, since items and attributes are not QML objects, changing the values they contain does not trigger property change notifications. If the above example had onItemsChanged or onAttributesChanged signal handlers, they would not be called when assigning individual entries in either property. If, however, the items or attributes properties themselves were reassigned to different values, then such handlers would be called.

@mirro said in Why is this 'keyValueList.push(KeyValue{})' code syntax incorrect in qml?:

Also, do I need to free memory in this 'Component.onDestruction'?

AFAIK no, because there is automatic garbage collection