Reimplementing event handler

Events in PyQt4 are processed often by reimplementing event handlers.

#!/usr/bin/python
# -*- coding: utf-8 -*-

"""
ZetCode PyQt4 tutorial 

In this example, we reimplement an 
event handler. 

author: Jan Bodnar
website: zetcode.com 
last edited: October 2011
"""

import sys
from PyQt4 import QtGui, QtCore


class Example(QtGui.QWidget):
    
    def __init__(self):
        super(Example, self).__init__()
        
        self.initUI()
        
    def initUI(self):      
        
        self.setGeometry(300, 300, 250, 150)
        self.setWindowTitle('Event handler')
        self.show()
        
    def keyPressEvent(self, e):
        
        if e.key() == QtCore.Qt.Key_Escape:
            self.close()
        
def main():
    
    app = QtGui.QApplication(sys.argv)
    ex = Example()
    sys.exit(app.exec_())


if __name__ == '__main__':
    main()

In our example, we reimplement the keyPressEvent() event handler.

def keyPressEvent(self, e):
    
    if e.key() == QtCore.Qt.Key_Escape:
        self.close()

If we click the Escape button, the application terminates.