How to control QTableView's Header using QAbstractTableModel

Question

Example below shows how 'My Column Name' header name is being centered from inside of the scope of TableView definition using:

self.horizontalHeader().setDefaultAlignment(QtCore.Qt.AlignHCenter | QtCore.Qt.AlignVCenter) 

While this works I would like to know how to control Header from inside of QAbstractTableModel using its headerData() method.

As is the headerData() returns the header name:

if orientation==QtCore.Qt.Horizontal:
            return QtCore.QVariant('My Column Name')

And it also returns a dummy QtCore.QVariant() if role!=QtCore.Qt.DisplayRole

    if role!=QtCore.Qt.DisplayRole:
        return QtCore.QVariant()

What other roles and values are available to be used with model's headerData()?

import sys, os
from PyQt4 import QtCore, QtGui
app=QtGui.QApplication(sys.argv)

class TableModel(QtCore.QAbstractTableModel):
    def __init__(self):
        QtCore.QAbstractTableModel.__init__(self)      

        self.items=['One','Two','Three','Four','Five','Six','Seven']

    def rowCount(self, parent=QtCore.QModelIndex()):   
        return len(self.items)
    def columnCount(self, index=QtCore.QModelIndex()):
        return 1

    def data(self, index, role):
        if not index.isValid() or not (0<=index.row()<len(self.items)):
            return QtCore.QVariant()

        item=str(self.items[index.row()])

        if role==QtCore.Qt.UserRole:
            return item

        if role==QtCore.Qt.DisplayRole:
            return item

        if role==QtCore.Qt.TextColorRole:
            return QtCore.QVariant(QtGui.QColor(QtCore.Qt.white))

        if role == QtCore.Qt.BackgroundRole:
            if index.row()%2:
                return QtCore.QVariant(QtGui.QColor("#242424"))
            else:
                return QtCore.QVariant(QtGui.QColor(QtCore.Qt.black))

    def headerData(self, column, orientation, role=QtCore.Qt.DisplayRole):
        if role!=QtCore.Qt.DisplayRole:
            return QtCore.QVariant()
        if orientation==QtCore.Qt.Horizontal:
            return QtCore.QVariant('My Column Name') 

class TableView(QtGui.QTableView):
    def __init__(self, parent=None):
        super(TableView, self).__init__(parent)

        self.setBackgroundRole(QtGui.QPalette.Base)
        p=self.palette()
        p.setColor(self.backgroundRole(), QtGui.QColor((QtCore.Qt.black)))
        self.setPalette(p)

        self.horizontalHeader().setResizeMode(QtGui.QHeaderView.Stretch)
        self.horizontalHeader().setDefaultAlignment(QtCore.Qt.AlignHCenter | QtCore.Qt.AlignVCenter)    

        font=QtGui.QFont()            
        font.setPointSize(9)        
        self.horizontalHeader().setFont(font)

        myModel=TableModel()
        self.setModel(myModel)      


view=TableView()
view.show()   
sys.exit(app.exec_())

Answer 1

Headers for table views are provided by QHeaderView. The doc describes which data roles are supported by it:

QHeaderView respects the following item data roles: TextAlignmentRole, DisplayRole, FontRole, DecorationRole, ForegroundRole, and BackgroundRole.

Here is an example of a headerData implementation (code is in C++):

QVariant
Model::headerData(int section, Qt::Orientation orientation, int role) const
{
    ...
    if (role == Qt::DisplayRole)
    {
        return QString("Header #%1").arg(section);
    }

    if (role == Qt::FontRole)
    {
        QFont serifFont("Times", 10, QFont::Bold, true);
        return serifFont;
    }

    if (role == Qt::TextAlignmentRole)
    {
        return Qt::AlignRight;
    }

    if (role == Qt::BackgroundRole)
    {
        return QBrush(Qt::blue);
    }

    if (role == Qt::ForegroundRole)
    {
        return QBrush(Qt::red);
    }
    ...
}

Also it must be noted that BackgroundRole most likely will be overriden by a widget palette and a general application style. You can check this answer about this.