Qt 4.8 Model/View Tutorial - Part 7

The following code is based on Qt 4.8 Model/View Tutorial - 3.2 Working with Selections.

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

'''
    PyQt4 conversion of Qt Model-View Tutorial
    
        Build a selectable tree view and update the application's
        Window Title with the selected item's content and 
        hierarchy level.
     
    NOTES:
    =====
        Tree is displayed as one expandable column.
      
last modified: 2012-01-28 jg
ref:
    http://developer.qt.nokia.com/doc/qt-4.8/modelview.html#3-2-working-with-selections
    
'''
from PyQt4.QtGui import (QApplication, QMainWindow, QTreeView, QStandardItem,
                         QStandardItemModel, QItemSelection)
from PyQt4.QtCore import (pyqtSlot, Qt, QModelIndex)

ROWS = 2
COLUMNS = 3

class MainWindow(QMainWindow):
    def __init__(self, parent=None):    # initialise base class
        super(MainWindow, self).__init__(parent)

        self.treeView = QTreeView(self)
        self.setCentralWidget(self.treeView)
        stdModel = QStandardItemModel()
        rootNode = stdModel.invisibleRootItem()

        # define a few items
        americaItem = QStandardItem("America");
        mexicoItem = QStandardItem("Canada");
        usaItem = QStandardItem("USA");
        bostonItem = QStandardItem("Boston");
        europeItem = QStandardItem("Europe");
        italyItem = QStandardItem("Italy");
        romeItem = QStandardItem("Rome");
        veronaItem = QStandardItem("Verona");

        # build the hierarchy
        rootNode.appendRow(americaItem);
        rootNode.appendRow(europeItem);
        americaItem.appendRow(mexicoItem);
        americaItem.appendRow(usaItem);
        usaItem.appendRow(bostonItem);
        europeItem.appendRow(italyItem);
        italyItem.appendRow(romeItem);
        italyItem.appendRow(veronaItem);

        # register the model
        self.treeView.setModel(stdModel)
        self.treeView.expandAll()

        # connect selection signal to slot
        selModel = self.treeView.selectionModel()
        selModel.selectionChanged.connect(self.selChanged)

    @pyqtSlot(QItemSelection, QItemSelection)
    def selChanged(self, newSel, oldSel):
        # get selected item's text
        index = self.treeView.selectionModel().currentIndex()
        selText = index.data(Qt.DisplayRole)

        # find the selected item's hierarchy level
        hierLevel = 1
        seekRoot = index
        while seekRoot.parent() != QModelIndex():
            seekRoot = seekRoot.parent()
            hierLevel += 1

        # update the window title
        showString = "{0}, Level {1}".format(selText, hierLevel)
        self.setWindowTitle(showString)

# main ========================================================================
def main():
    import sys

    app = QApplication(sys.argv)
    mw = MainWindow()
    mw.setWindowTitle("Tree View Selections")
    mw.show()

    sys.exit(app.exec_())

if __name__ == '__main__':
    main()