QSortFilterProxyModel lessThan is never called.

[atomic]

I tested this code with QStandardItemModel and it works fine, lessThan is called properly so I think that problem is in my CustomTableModel. Maybe I forgot about some important function which should be reimplemented?

[atomic]

Very stupid mistake =-=. And you can see it in my code, exactly in mainwindow.h.
First I tested sorting data with QSortFilterProxyModel and when I wrote my CustomSortFilterProxyModel I forgot to change the definitions of these classes in mainwindow.h....

Sorry for that.

But I have one more question - it is a good way for sort table by multiple column? or in Qt we have better way for this?

[anda_skoa]

You can always sort inside your model.
I usually prefer that over using a proxy if the sorting gets more complicated.

Cheers,
_

[d_stranz]

But I have one more question - it is a good way for sort table by multiple column?

QSortFilterProxyModel only supports sorting on a single column. You could probably write a lessThan() method that would do a multi-level sort for a custom QSortFilterProxyModel, but the proxy is still going to maintain its state under the assumption that it is a single-column sort. As anda_skoa says, it is usually easier to do this in the source model if the sorting is complex.

[yeye_olive]

There is a reason for the focus on single-column sorting. If each sort is stable (which is usually expected in a UI), then you can get the lexicographic order on columns c1..cn by sorting by cn, then cn-1, ..., then c1. E.g. to sort files by date, then name, you can first click on the "name" column, then on the "date" column.

[d_stranz]

to sort files by date, then name, you can first click on the "name" column, then on the "date" column.

I don't think that works in a custom model (or even in the off-the-shelf QSortFilterProxyModel) - unless the model (or proxy) implements such multi-column sort behavior. How does a standard QSortFilterProxyModel know to maintain the sort on one column that contains duplicates while sorting a second column with respect to those duplicates? As far as I have seen, sorting on any column occurs independently of other columns and results in all rows being reordered solely on the sort order of the chosen column.