formatting a QTableView header

mzimmers

Do I need to derive a subclass from QStyle to do this?

kshegunov

@mzimmers said in formatting a QTableView header:

Do I need to derive a subclass from QStyle to do this?

Yes. But maybe try QProxyStyle instead, so you have less work to do.

mzimmers

I'm afraid that I'm going to have to temporarily abandon this thread. I just don't know enough about styles/hints/etc. and I don't have time to give it the attention it deserves.

Thanks for the assistance; I'll get back to this as soon as I can.

mzimmers

OK, I have a little spare time now. I've copied this code (from the page):

class MyProxyStyle : public QProxyStyle
{
  public:
    int styleHint(StyleHint hint, const QStyleOption *option = 0,
                  const QWidget *widget = 0, QStyleHintReturn *returnData = 0) const override
    {
        if (hint == QStyle::SH_UnderlineShortcut)
            return 0;
        return QProxyStyle::styleHint(hint, option, widget, returnData);
    }
};

What would you suggest I use instead of SH_UnderlineShortcut to test whether my styling is taking effect? (Given the trouble we were having earlier.)

Thanks.

SGaist

Hi,

How did you set your custom style ?

mzimmers

Hi SGaist - like this:

    MyProxyStyle *mps = new MyProxyStyle;
    ui->tableView->setStyle(mps);

SGaist

What if you set it application wide ?

mzimmers

I can try that. What I was asking for, though, was a style hint that would be readily apparent in my app. The one in the example might work perfectly, but I'd never see it without implementing any shortcuts (at least I think not).

mzimmers

For what it's worth, this line of code produces expected results:

ui->tableView->setStyleSheet("background-color: red");

But this one does not:

    ui->tableView->horizontalHeader()->setStyleSheet("background-color: red");

So the problem seems to be in the header object, doesn't it?

kshegunov

You don't need a style hint if you're trying to override the painting. You'd have to reimplement QStyle::drawControl and handle the QStyle::CE_Header control. Something like this:

class MyProxyStyle : public QProxyStyle
{
public:
    void drawControl(ControlElement element, const QStyleOption *option, QPainter *painter, const QWidget *widget = nullptr) const override
    {
        if (element != QStyle::CE_Header)  {
             baseStyle()->drawControl(element, option, painter, widget);
             return;
        }

        // Paint here ...
    }
};

It's been a long time since I last played with the styles, but I hope this is of help.

VRonin

You might want to try just adding QApplication::setStyle(QStyleFactory::create("Fusion")); to your main(). The fusion style supports the styling of QHeaderViews even on windows

mzimmers

@VRonin using that style, along with the style sheet, did in fact paint my header background red. Thank you!

Now, for creating a separation line under the header...is it recommended that I try to use a style sheet, or QStyles?

VRonin

Try the fast way, use stylesheet

mzimmers

Interesting results...I tried this:

    ui->tableView->horizontalHeader()->setStyleSheet("border-bottom: 5px solid red");

And got this:

I must be malforming the stylesheet (I pulled the contents directly from a CSS example I found online), but the curious (to me) part is I'm now getting an underline (actually a bottom border, I guess) across the entire header, but only the middle column is painted red (which I don't understand either).

Thoughts?

VRonin

http://doc.qt.io/qt-5/stylesheet-examples.html#customizing-qheaderview

mzimmers

Disregard my image above: the setting of the red background was due to a separate experiment I'd been performing on the model. It was disguised when I set the entire header view to red, then reappeared when I removed that CSS in favor of the bottom border.

I'd actually read that page you referenced, but I don't fully understand the syntax. I can see that everything in the braces is Qt style information, but what is the context in which they're used? For example, in this:

QHeaderView::section

What is "section?"

VRonin

it's the sub element inside the headerview. That style applies to every single row/column header cell

mzimmers

Ah, I see (I think). Well, the upshot is that I can remove all of my stylesheet settings. The use of the Fusion style gave me the desired look:

Which is fortunate, because this attempt at stylesheet setting didn't work:

    ui->tableView->horizontalHeader()->setStyleSheet("border-bottom: 5px solid red");

Not sure why (the red background worked).