Question

My custom table model derives from QAbstractTableModel and is then displayed in a QTableView.

Looks like this:

I would like to change the text color for certain row headers, which can be decided in the model. Is it possible to color certain headers from there? I couldn’t find a way so far. What I found was about setting background/text color for all headers, not for special few. The color is supposed to be kind of markup for the user.

Answer 1

What you have to do is reimplement QAbstractTableModel::headerData().
Depending on the value of section (header index starting at zero) you can individually style the header items.
The relevant values for foreground (=text color) and background in Qt::ItemDataRole are Qt::BackgroundRole and Qt::ForegrondRole

E.g. like this:

QVariant MyTableModel::headerData(int section, Qt::Orientation orientation, int role) const {
  //make all odd horizontal header items black background with white text
  //for even ones just keep the default background and make text red
  if (orientation == Qt::Horizontal) {
    if (role == Qt::ForegroundRole) {
       if (section % 2 == 0)
          return Qt::red;
       else
         return Qt::white;
    }
    else if (role == Qt::BackgroundRole) {
       if (section % 2 == 0)
          return QVariant();
       else
         return Qt::black;
    }
    else if (...) {
      ...
      // handle other roles e.g. Qt::DisplayRole
      ...
    }
    else {
      //nothing special -> use default values
      return QVariant();
    }
  }
  else if (orientation == Qt::Vertical) {
      ...
      // handle the vertical header items
      ...
  }
  return QVariant();
}