Qt ProxyModel性能问题

Question

So I have this Qt application with a QTreeView with a custom model (derived from QAbstractItemModel ) and a custom model proxy for filtering (derived from QSortFilterProxyModel ). More or less straightforward (somewhat similar to the and works fine ) and works fine in terms of functionality.

The view shows a two-column tree with key-value pairs. The keys are updated very rarely but the values are updated frequently (a lot of entries with several updates every second each). In the proxy model I overload filterAcceptsRow to define visibility based on the key column. But every value change emits a dataChanged signal causing the view to call the proxy ( filterAcceptsRow ) again and that call is somewhat expensive (evaluate a regex on the element and its children). There is some room for optimization in filterAcceptsRow by caching all the calculations but it would be preferred to limit the calls to that function. Can it somehow be limited what columns trigger the calls to the proxy?

You have any advise for me?

Edit: Thanks for your input. I wasn't aware of dynamicSortFilter . I disabled dynamic sorting and also I connected the dataChanged -signal from the model to see if the key-column was changed and called invalidate in that case. That solved it.

Answer 1

If you look at the code for QSortFilterProxyModel you'll see that most of the work is only done when dynamicSortFilter is enabled. I guess that is the case for your code.

Can you live without it? Maybe call invalidate() once every 100 updates or second, depending on which happens first.

Answer 2

I had the same problem, solved it by emitting dataChanged signal from the proxy model itself, not from the main model. Alternatively, you can disable dynamic sort/filtering ( dynamicSortFilter property) and call it manually when you want to filter or sort.

Also, I'm not sure, but maybe simply specifying the column in dataChanged signal will do it for you.