filterAcceptsRow from QSortFilterProxyModel is not called when item state of source model changed

[Please_Help_me_D]

@Christian-Ehrlicher I just created example based on QStandardItemModel(). It just beacause my real model depends on external library. But anyway this example could help me to understand how to "connect" checked items with proxy model
Here is the zipped project:
https://yadi.sk/d/Kft2dNpTEuTEeQ

[Christian Ehrlicher]

Your testcase is wrong - you can't simply cast the internal pointer to a QStandardItem. You need

auto sm = static_cast<QStandardItemModel*>(sourceModel());
QStandardItem* item = sm->itemFromIndex(index);

Then it works as expected. The only thing is that the children are only visible when the parent was checked once but this is an implementation problem in your filterAcceptsRow() function.

btw: setDynamicSortFilter() is not needed as I saw now

[Please_Help_me_D]

@Christian-Ehrlicher thank you!
Now I'm trying to overcome the thing that children are not displayed if their parent is not checked

[Christian Ehrlicher]

@Please_Help_me_D You have to adjust your filterAcceptRow function to check for the children if one is checked.

[Please_Help_me_D]

@Christian-Ehrlicher filterAcceptsRow doesn't get called when I check the child from unchecked parent. And when I launch the app all children are UnChecked.
Or I misunderstand something?
On the picture I checked a child but filterAcceptsRow was not called

[Please_Help_me_D]

I just understood that filterAcceptsRow get invoked only if parent of index is displayed in proxy model. Oherwise proxy model thinks that it is not worth to insert row in proxy model.
I can't understand what method of QSortFilterProxyModel I should rewrite to make the proxy to add each checked items regardless of its parent is shown or not.
Does anybody know?

[Christian Ehrlicher]

@Please_Help_me_D said in filterAcceptsRow from QSortFilterProxyModel is not called when item state of source model changed:

Does anybody know?

You can emit a dataChanged() signal for the parents to trigger a recheck.

[JonB]

@Please_Help_me_D

I just understood that filterAcceptsRow get invoked only if parent of index is displayed in proxy model

I truly do not know if the following has any relevance to your situation. But it only takes 5 seconds to try, and you can throw away if it makes no difference.

Qt introduced https://doc.qt.io/qt-5/qsortfilterproxymodel.html#recursiveFilteringEnabled-prop. The default is false. Try setting it to true and see whether that causes it to evaluate filterAcceptsRow() against whatever node you are saying it does not currently look at?

[Please_Help_me_D]

@Christian-Ehrlicher I'm thinking about this but I'm trying to avoid sending items that were not changed via dataChanged() signal.
@JonB Yes I've already tried it but this doesn't solve my task. It slightly changes the behaviour of proxy model but not in a way I expect it to be

[Please_Help_me_D]

I decided to make the following:
I'm going to make all the items (except the root) checkable. When I change checkstate of a item to Qt::Checked then this item also changes checkState of its parent to Qt::PartiallyChecked.
So this chain should work but I have not finished it yet