Qt-jambi-interest Archive, June 2007
Problems with QTableView
Message 1 in thread
Hi folks,
I'm having an issue with QTableView since Qt Jambi 0.1. It looks like
QTableView isn't updated as expected although this worked in QtJambi
0.1_beta2. My testcase builds up a simple table with an also simple
QAbstractTableModel. This model will return 0 columns and rows for the
first two seconds the program runs, then layoutChanged is emited and
columnCount gets 4 and rowCount gets 15. This thing works flawlessly
with beta2 but the table remains empty with 0.1_final. Firing other
signals like dataChanged or headerChanged doesn't help, still empty. So
which signal should be emitted when the modeldata updates?
My testcase can be found here:
http://crosswidgets.sourceforge.net/QtTest.java
I found out that there's a difference in methodcalls between beta2 and
final by printing the stack trace of an Exception ( if (done) new
Exception().printStackTrace(); ) in check(). It seems that beta2 queries
all methods from the model whereas final only queries columnCount() and
nothing else.
More Details: I previously used Qt Jambi 0.1_beta2 32bit for Linux, now
I use the 64bit version of 0.1_final.
Best regards
Georg Schild
Message 2 in thread
Hi,
I had the same problem when I switched from Beta 2 to the final release.
Just call reset() instead of layoutChanged() and it should work again.
Regards,
Andreas
Message 3 in thread
Hi,
Andreas Heck schrieb:
> I had the same problem when I switched from Beta 2 to the final release.
> Just call reset() instead of layoutChanged() and it should work again.
thank you, that function did it. I didn't search for some function from
the model which does the update, I thought it would either be a signal
in the model or an update-function of the QTableView.
Best regards
Georg Schild
Message 4 in thread
Georg Schild wrote:
> Hi folks,
>
> I'm having an issue with QTableView since Qt Jambi 0.1. It looks like
> QTableView isn't updated as expected although this worked in QtJambi
> 0.1_beta2. My testcase builds up a simple table with an also simple
> QAbstractTableModel. This model will return 0 columns and rows for the
> first two seconds the program runs, then layoutChanged is emited and
> columnCount gets 4 and rowCount gets 15. This thing works flawlessly
> with beta2 but the table remains empty with 0.1_final. Firing other
> signals like dataChanged or headerChanged doesn't help, still empty. So
> which signal should be emitted when the modeldata updates?
You should not emit these signals yourself. They should be emitted by
the QAbstractItemModel when you explicitly tell it that you have added
rows and colums. This is done using the functions beginInsertRows() and
beginInsertColumns(). Between begin() and end() you update your
datastructure so that rowCount() and columnCount() returns the right
values for the new layout.
private void check() {
System.out.println("checking " + done + " " + first);
if (System.currentTimeMillis()-2000 >= oldTime) {
done = true;
if (!first) {
first = true;
beginInsertRows(null, 0, 15);
beginInsertColumns(null, 0, 4);
// update datastructure...
endInsertRows();
endInsertColumns();
}
}
}
best regards,
Gunnar
