QTableView - scroll performance changed from 4.0 to 4.1 and 4.2

**budul** · 8th November 2006, 13:01

Yes, you are surely right. Actualy i'm using 20x10 widgets, just to fill screen. Then i'm reusing them somehow. Simply i needed to have all widgets ready for edit and they are more complicated in real. Imagine some stock monitoring application with progress bars and custom designed widgets to edit and monitor courses. Probably "not focuesd ones" i should just paint. But anyway i have to solve my transfer to 4.2 from 4.0. And in 4.0 scroll was not a problem at all. So what changed here in the meantime? Is there another way out than change in design? Of course, to stay with 4.0 is not the answer.

Thanks again!
B.

**wysota** · 8th November 2006, 14:34

Probably something was optimised or fixed, but as you are using the framework in a very... emmm... uncommon way

the probably that optimisation turned out to be a slowdown for you or you might have been benefiting from a bug and when the bug was fixed the benefit vanished.

Maybe you should use a QScrollArea filled with widgets instead of a table view?

**budul** · 8th November 2006, 20:14

Please, tell me how one can easily paint widget which contains 3-4 other widgets to item in TableView. Simply i need these features of TableView as resizing columns, hiding columns. That's why i'm using table.

Attached is the picture of what i've got and need. How this can be done more optimized way?
Thanks a lot!
B.

**wysota** · 8th November 2006, 21:07

Originally Posted by budul

Please, tell me how one can easily paint widget which contains 3-4 other widgets to item in TableView.

Create a custom widget with the other widgets inside it (in a layout) and then use QAbstractItemView::setIndexWidget() to set the widget. If you need the widget to be able to edit the data inside the model then set it as an editor instead.

**budul** · 8th November 2006, 21:32

That's exactly what i'm doing, but via delegate. But my problem is that even if i set 20x10 widgets to the table i've got very poor performance. How can i create table with 20x10 custom widgets and will have good response from the GUI in 4.2?

I really can't have just text in the cells. :-(

Thanks again.
B.

**wysota** · 8th November 2006, 23:36

Each subsequent permanent editor takes longer to add to the view, so you might want to avoid those. Using index widgets should be faster as they are not updated by the view.

In your case maybe it would be best to get rid of the view and just emulate the columns by using a QHeaderView and a custom layout (you would probably need to implement an own grid layout, but it shouldn't be too hard).

**budul** · 23rd November 2006, 10:10

Solution which works much better with 4.2 is to leave QTableWidget as Wysota advised. So QHeaderView + QGridLayout in QScrollArea works fine for horizonatl scrolling now. It is different with resizing columns (as table does) and hiding columns. It's not so fast as before and as one can see with use of QSplitter, but it's not big deal for me. Thanks anyway.