[SOLVED] QTableView::setSortingEnabled() doesn't really work

[d2uriel]

Dear Qt community,

I'm facing a small problem with setSortingEnabled() method of QTableView class. I'm using a standard QTableWidget with selectionMode set to ExtendedSelection and selectionBehavior set to SelectRows. First column items are something like this:

@QTableWidgetItem* _pDateTime = new QTableWidgetItem();
_pDateTime->setFlags(_pDateTime->flags() ^ Qt::ItemIsEditable);
_pDateTime->setData(Qt::EditRole, QDateTime::fromString(json["dateTime"].toString(), "dd.MM.yyyy HH:mm:ss"));@

Before setting all QTableWidgetItem's in the table I disable sorting by calling setSortingEnabled(false);. Now as soon as all items are set in position I'm re-enabling sorting but it does nothing. In the docs it says:

Note: . Setting the property to true with setSortingEnabled() immediately triggers a call to sortByColumn() with the current sort section and order.

I guess there's a problem with the current sort section - how can I change it to be column 0? I've tried doing like this:

@tableWidget->horizontalHeader()->setSortIndicator(0, Qt::DescendingOrder);@

but this only crashes the table widget (meaning that it shows the items only in the first column). Any ideas?

Thank you in advance.

Edit: I just noticed one weird thing. My table widget has 12 columns and the last one is hidden. If I call:

@tableWidget->horizontalHeader()->setSortIndicator(11, Qt::DescendingOrder);@

it actually sorts the table without crashing the widget.

[xcoder]

Aloha,

I'm just guessing here, but you can always try to call the "sortByColumn":http://qt-project.org/doc/qt-5.1/qtwidgets/qtableview.html#sortByColumn method directly. And have the sorting enabled always.

If you do it directly you can specify which column to use.

Happy Coding

[d2uriel]

I ran some tests and it seems that setSortingEnabled(true) does try to sort the table so calling sortByColumn() manually does the job but significantly increases table setup.

I want to have this time as small as possible. If I don't turn sorting off and on between item insertion then the time to setup the table is around 340ms. If I have it turned off and on it increases to 380ms and if I manually call sortByColumn() it goes up to 420ms.

I have to disable sorting during item insertion because otherwise it's going to mess things up. I'm inserting the items in a loop to each row and docs suggest to turn sorting off for that.

PS: Of course I'm disabling sorting before any item is inserted and enabling it after all items are inserted.

[xcoder]

Aah, I understand your point, indeed, the approach I provided is definitely not the best approach, why execute something twice if you can do it once.

Again just guessing, but maybe, just maybe you could "set the current index":http://qt-project.org/doc/qt-5.1/qtwidgets/qabstractitemview.html#setCurrentIndex to 0th columns, before enabling the sorting.

OR maybe even easier way, would be to call "setCurrentCell ":http://qt-project.org/doc/qt-5.1/qtwidgets/qtablewidget.html#setCurrentCellmethod method from QTableWidget and set cell to 0,0

I hope it helps

[d2uriel]

Ugh, I guess I was wrong saying that sortByColumn() is running twice. I made some changes in the code and it seems that the call from setSortingEnabled() is not being executed.

My mistake, sorry.

[xcoder]

Oh what I meant about the sortByColumn and setSortingEnabled, is that setSortingEnabled already executes it, and you eventually do sorting twice.

I don't know if we are on the same page :D

Anyway, let me know if you find a solution

[d2uriel]

Hmm... I found the solution!

@tableWidget->horizontalHeader()->setSortIndicatorShown(true);
tableWidget->horizontalHeader()->setSortIndicator(0, Qt::DescendingOrder);@

And now setSortingEnabled() actually sorts the table.