Automatic update of listView and c++ model

  • Hi,

    I'm trying to write a c++ model like the one describe in the example (Animal model). I would like to add a function to modified the model. I've add a Q_INVOKABLE function in the AnimalModel class. 

    @ void AnimalModel::changeData(int number,QString type, QString size)
    if ( number >= 0 && number < m_animals.count())
    qDebug() <<"number:"<<number << " new type : "<< type<<" new size : "<< size;
    m_animals[number].m_type = type;
    m_animals[number].m_size = size;
    emit dataChanged(index(0),index(m_animals.count()));

    I see my message in the warning window but my view never update. I've read Model subclassing reference but I haven't found a thing to help me.

    Thanks for reading me.

  • No idea what your AnimalModel is and where it comes from, but it looks to me like you are changing your underlying data structure (m_animals) and then tell the view that the model has changed. But you never update the model (or tell the model that the underlying data has changed).

  • Animal model is the one defined "here":
    I've only change the Animal class to have all membres public.

    My model is a QList of Animal, which are modified line 6 and 7 and I guess I warn the model is updated line 8.

  • Sorry, that was a very confusing response from me...
    Now that I see the code, I realise there's nothing wrong with your code, except for one tiny problem, and that is that when you emit dataChanged the second argument is out-of-range. It should be:
    @emit dataChanged(index(0), index(m_animals.count() - 1));@
    But that will invalidate the entire model, so really, you should just do:
    @emit dataChanged(index(number), index(number));@

  • That's what I tried first but it didn't work, so I changed it just to see.

    If I did all correctly I should raise it as a bug ?

  • Are you sure? I tried it, and it works just fine for me.

  • Yeah you're right that's working... I don't konw why this was'nt working the first time.
    Thanks a lot.

  • Great. You're welcome!

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