Item on Repeater create and destroy when model changed
-
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) } } -
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.
-
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 ?
-
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 ?
@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.
