Item on Repeater create and destroy when model changed

[helenebro]

Hi,
I have a repeater with model given by C++ part. There are several field on this model : "name", "value", ... The field "value" change a lot.
I have notice all item are destroy and recreate each time model change. Is that serious ? Is an other way to do this ?

Repeater {
    id:repeater
    model: myApp.data
    Rectangle {
        width: 300
        height: 300
	border.color:"black"
        Row {
           Text {text:modelData.name}
           Text {text:modelData.value}
	} 
	Component.onCompleted: console.log("complete", index)
        Component.onDestruction: console.log("destruction", index)              
    }
}

[jpnurmi]

What is the type of myApp.data? If you make it a proper model, Repeater is able to listen to fine-grained notifiers and act correspondingly. If it's some sort of JS-array/object, Repeater gets a notification that the JS-array changes, but doesn't know what exactly changed. It has to rebuild the entire representation, because it basically corresponds to changing the entire model.

[helenebro]

It's a QJsonArray :

    Q_PROPERTY(QJsonArray data READ data WRITE setData NOTIFY dataChanged)

Do you mean it's better to have a QQmlListProperty<MyObject> with MyObject :

class MyObject : public QObject
{
	Q_OBJECT
	Q_PROPERTY(QString name READ name NOTIFY nameChanged)
	Q_PROPERTY(int value READ value NOTIFY valueChanged)
public :
	...
};

Is there an influence over performance of application ?

[jpnurmi]

@helenebro It's better to use either QAbstractItemModel (or any descendant) in C++, or ListModel (or other ready-made models) in QML. Since you have a QJsonArray, you could implement a simple QAbstractListModel around it. Just make sure to emit the appropriate signals by calling beginInsertRows() + endInsertRows() when you insert rows, for instance.

[helenebro]

Ok. Thank you for your answer.
I never use QAbstractListModel. Do you have some keys to start ?

What is difference between using QAbstractListModel and QQmlListProperty ?
In which case is it better to use them ?