QML ListView does not reflect updates from its C++ data model [Solved]

ondrejandrej

You are creating a model, but it goes out of scope immediately after constructor terminates (I suppose your last code snippet is in a constructor).

You should ensure that the model remains in existence while the QML view is showing, e. g. by allocating on heap:
@MyDataModel *myDataModel = new MyDataModel(this);
context->setContextProperty("myDataModel", myDataModel);@

kwisatz

I've tried to allocate it at the heap as well and the ui remains unchanged. Originally, myDatamodel was a private member of its parent's class. The code snippet was modified to simplify my question.

ondrejandrej

You are using "it's" wrongly. Have a look at http://www.elearnenglishlanguage.com/blog/english-mistakes/its/ . You have it also in the title.

kwisatz

:D Thanks for pointing that out!

p3c0

bq. I just tried inserting that, and my Application Crashed as soon as that code was invoked. Narrowed it down to endResetModel() being the culprit.

I have been using this approach in all my projects where ListView is used. It worked all the time.
Why are you using QDeclarativeView ? Aren't you using Qt 5 ?

ondrejandrej

[quote author="kwisatz" date="1421877712"]:D Thanks for pointing that out!
[/quote]
It's good that you fixed it :D

kwisatz

Sorry, should have made this clear earlier on, I'm using Qt 4.8.4.

[quote author="p3c0" date="1421902494"]bq. I just tried inserting that, and my Application Crashed as soon as that code was invoked. Narrowed it down to endResetModel() being the culprit.

I have been using this approach in all my projects where ListView is used. It worked all the time.
Why are you using QDeclarativeView ? Aren't you using Qt 5 ?[/quote]

p3c0

Well then I'm not sure why it crashes. Qt 4.8.4 still is quite old in Qt4 series. Can you try it on Qt 4.8.6 ?

kwisatz

I've tried this with 4.8.6 but to no avail

At the moment, I'm unable to move to Qt5. I'm cross-compiling for an Embedded Linux System as well, there's a fair amount of porting involved to move to Qt5.

kwisatz

Okay, I did manage to get this to work finally.

When clearing data, I used:
@ beginResetModel();
m_data.clear();
endResetModel();@

When removing an individual item in the data, I used:

@ beginRemoveRows(QModelIndex(), index, index);
m_data.removeAt(index);
endRemoveRows();@

And I worked on this bit of code separately from my main application. Will have to see what kind of fun awaits when I merge the changes with the rest of the application ;)

Appreciate the help folks!