Accessing property by name or by READ function ?

Mixlu

Hello,

I have a list of model in a property declared as follow :

Q_PROPERTY(QQmlListProperty<MyModel> listModel READ getListModel NOTIFY listModelChanged)

I use this property in QML in a ListView as follow (only relevant code is shown):

ListView {
    model: Backend.getListModel()
}

My question is, should I declare my ListView model with the READ function (model: Backend.getListModel()) or just with the property name (model: Backend.listModel) ?
Is there any difference between these two options ?

PS : I am working with Qt 5.14.2 with MinGW (windows)

KroMignon

@Mixlu said in Accessing property by name or by READ function ?:

My question is, should I declare my ListView model with the READ function (model: Backend.getListModel()) or just with the property name (model: Backend.listModel()) ?
Is there any difference between these two options ?

Yes, there is a big difference!
By using model: Backend.getListModel() the affectation will be static, model will be set once at Item load.
With model: Backend.listModel the affectation will be dynamic, on each listModelChanged signal, model will re-read Backend.getListModel().

Mixlu

@KroMignon Ok I see, it's clear. Thank's for your reply!

GrecKo

Note that in general you should not mark your properties' READ functions as slot or Q_INVOKABLE, just make it a simple public function.
This way you can only access it by name and have a clear QML api.

fcarney

@GrecKo This is interesting as the refactor option in creator always makes the READ function a slot. Thanks for the insight.

GrecKo

@fcarney This will be configurable in Qt Creator 4.15 : https://bugreports.qt.io/browse/QTCREATORBUG-15779 https://codereview.qt-project.org/c/qt-creator/qt-creator/+/310832