How can we set the width of a vertical header in a TableView when new rows are added.?

[saratchand.kandukuri]

I tried using the QHeaderView, kept the orientation as Vertical. Then with the help of the sizeHint of the QHeaderView class like below:

@QSize QHeaderView::sizeHint() const
{
Q_D(const QHeaderView);
if (d->cachedSizeHint.isValid())
return d->cachedSizeHint;
d->cachedSizeHint = QSize(0, 0); //reinitialize the cached size hint
const int sectionCount = count();

// get size hint for the first n sections
int i = 0;
for (int checked = 0; checked < 100 && i < sectionCount; ++i) {
    if (isSectionHidden(i))
        continue;
    checked++;
    QSize hint = sectionSizeFromContents(i);
    d->cachedSizeHint = d->cachedSizeHint.expandedTo(hint);
}
// get size hint for the last n sections
i = qMax(i, sectionCount - 100 );
for (int j = sectionCount - 1, checked = 0; j >= i && checked < 100; --j) {
    if (isSectionHidden(j))
        continue;
    checked++;
    QSize hint = sectionSizeFromContents(j);
    d->cachedSizeHint = d->cachedSizeHint.expandedTo(hint);
}
return d->cachedSizeHint;

}@

Then I used the geometriesChanged function of the QTableView. which is:
@
void QTableView::updateGeometries()
{
Q_D(QTableView);
if (d->geometryRecursionBlock)
return;
d->geometryRecursionBlock = true;

int width = 0;
if (!d->verticalHeader->isHidden()) {
    width = qMax(d->verticalHeader->minimumWidth(), d->verticalHeader->sizeHint().width());
    width = qMin(width, d->verticalHeader->maximumWidth());
}
int height = 0;
if (!d->horizontalHeader->isHidden()) {
    height = qMax(d->horizontalHeader->minimumHeight(), d->horizontalHeader->sizeHint().height());
    height = qMin(height, d->horizontalHeader->maximumHeight());
}
bool reverse = isRightToLeft();
 if (reverse)
     setViewportMargins(0, height, width, 0);
 else
     setViewportMargins(width, height, 0, 0);

// update headers

QRect vg = d->viewport->geometry();

int verticalLeft = reverse ? vg.right() + 1 : (vg.left() - width);
d->verticalHeader->setGeometry(verticalLeft, vg.top(), width, vg.height());
if (d->verticalHeader->isHidden())
    QMetaObject::invokeMethod(d->verticalHeader, "updateGeometries");

int horizontalTop = vg.top() - height;
d->horizontalHeader->setGeometry(vg.left(), horizontalTop, vg.width(), height);
if (d->horizontalHeader->isHidden())
    QMetaObject::invokeMethod(d->horizontalHeader, "updateGeometries");

@

I called this function in a signal slot connection when new columns are added. But still the size is the minimumwidth(20) or something which I set in the starting.. Even though there are index in the vertival footer with numbers upto 5000 and these are displayed so small because of 20 minimumwidth I set.

If what I think is wrong, please sugggest another idea. I just want it to change and get set dynamically.

Thanks in advance.

[SGaist]

Hi,

Something is not clear, QHeaderView should resize itself automatically. What problem did you encounter ?

[saratchand.kandukuri]

Hii SGaist

The width of the vertical header is not set automatically. I dont know why.. Can you tell me why? The minimum width that I set in the constructor is the fixed width but changing even though there are more numbers of more width added.

[SGaist]

Can you show a minimal sample for code that shows that the header is not resized ?

[saratchand.kandukuri]

Hey SGaist, I found the way for setting it. I solved it. I used a signal from the QHeaderView : sectionCountChanged(int, int).. I connected it to a public slot in my class that inherits QTableView.
In the connected slot, I took the font of the tableview and then considered the width of the last number of the index in the vertical header. There could be a small offset but I added a offset of 4 pixels and set this as the minimumwidth of the vertical header. The width gets updated when new rows are added.

my header file containing the slot is:
@
public slots:
void slotVerticalSectionsCountChanged(int xOld, int xNew);
@

My cpp file contains the connect in the constructor like:
@
connect(verticalHeader(), SIGNAL(sectionCountChanged(int, int)), this, SLOT(slotVerticalSectionsCountChanged(int, int)));
@

The slot is defined as follows:
@
void xxxxxxxx::slotVerticalSectionsCountChanged(int xOld, int xNew)
{
Q_UNUSED(xOld)
Q_UNUSED(xNew)

// Get the current no. of rows of the table view
QString tString = count(); 

// QString tString = xNew; // xNew is the current rows

// The font of the current table or the vertical header is taken for calculating the width of the index value of the last index
QFont font = verticalHeader()->font();
QFontMetrics tFm(font);

// 4 pixels are added as buffer pixels since the margins slightly affect the view of the vertical header
int width = tFm.width(tString) + 4;

// We set this value as the width
verticalHeader()->setMinimumWidth(width);

}
@

Hope this could be a help for anyone in the future. Cheers!