How to Access ListModel from C++

Kenz Dale

I have found many posts related to getting custom models into QML, but in my case I am very happy with the ListModel and simply want to make it available to C++. However, I am running into a crash which gives no feedback and I'm at a bit of a loss for how to continue.

Here is the relevant code snippet from how I try accessing the model from C++

C++:

Q_PROPERTY(QAbstractListModel* model READ model WRITE setModel)
QAbstractListModel* model() const {return model_;};
void setModel(QAbstractListModel *model){};

QAbstractListModel* model_;

QML:

ListModel {
    id: textModel
}

TextBalloon {
    model: textModel
}

Output:

QML debugging is enabled. Only use this in a safe environment.
05:38:08: The program has unexpectedly finished.

Very frustrating not to have a more useful error message. It just bombs out. The debugger is no help, it gets stuck on view.setSource(QUrl("qrc:/qml/main.qml"));.

The program loads correctly when I remove the model: textModel line.

Anyone have a working example of accessing the ListModel from C++?

dheerendra

Best thing is to avoid accessing qml objects from c++. If you do some mistake it will crash like this. You have go deep inside object tree to find your list model and then access it

MrShawn

See if this helps.

https://www.youtube.com/watch?v=9BcAYDlpuT8

GrecKo

Can you post a simple example where your code crashes so that we can reproduce it ?
What is the body of your setModel method ?

Accessing QML objects like that is perfectly fine and not a bad practice since you are passing it to c++, it's not the c++ retrieving it with a findChild call.

The video linked is about using a c++ model in a QML view, that's not relevant to OP's problem.

Kenz Dale

I'm attributing this to the build system. The problem resolved itself when I started from a blank generic example and copied over the code before putting it back into the problematic app.

The only thing I can think of is that perhaps I needed to do a make clean.