formatting a QTableView header

[mzimmers]

How do I convert a QVariant to a QBrush?

[kshegunov]

QBrush brush = variant.value<QBrush>();

However you can inspect the data directly in the variant as well, as far as I can see in the watch.

[Christian Ehrlicher]

@mzimmers: are you working on windows? https://bugreports.qt.io/browse/QTBUG-31804

[mzimmers]

@Christian-Ehrlicher yes, I am, and that would seem to be the problem here. Plus, there's this:

Widget::Widget(DeviceModel *d, QWidget *parent) : QWidget(parent), ui(new Ui::Widget)
{
...
    ui->tableView->horizontalHeader()->setBackgroundRole(QPalette::Window);

So, do I need to create a QStyle for the underlining, and set that on my header view?

[kshegunov]

@mzimmers said in formatting a QTableView header:

So, do I need to create a QStyle for the underlining, and set that on my header view?

I'd advise at least trying if that will fix the issue.

[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