import sys
from PyQt4 import QtCore, QtGui


class StartQT4(QtGui.QMainWindow):
    def __init__(self, parent=None):
        QtGui.QWidget.__init__(self, parent)
        self.ui = Ui_MainWindow()
        self.ui.setupUi(self)

    def keyPressEvent(self, event):
        if type(event) == QtGui.QKeyEvent:
             #here accept the event and do something
            print event.key()   # Key Code gets printed to the console
            event.accept()
            self.ui.labelLetter.setText(event.text())

class Ui_MainWindow(object):
    def setupUi(self, MainWindow):
        MainWindow.setObjectName("MainWindow")
        MainWindow.resize(800, 600)
        MainWindow.setAutoFillBackground(True)
        self.centralwidget = QtGui.QWidget(MainWindow)
        self.centralwidget.setObjectName("centralwidget")
        self.labelDirections = QtGui.QLabel(self.centralwidget)
        self.labelDirections.setGeometry(QtCore.QRect(240, 140, 271, 191))
        font = QtGui.QFont()
        font.setFamily("Tempus Sans ITC")
        font.setPointSize(36)
        self.labelDirections.setFont(font)
        self.labelDirections.setAutoFillBackground(True)
        self.labelDirections.setObjectName("labelDirections")
        self.labelLetter = QtGui.QLabel(self.centralwidget)
        self.labelLetter.setGeometry(QtCore.QRect(240, 350, 271, 141))
        font = QtGui.QFont()
        font.setFamily("Tempus Sans ITC")
        font.setPointSize(72)
        self.labelLetter.setFont(font)
        self.labelLetter.setFrameShadow(QtGui.QFrame.Plain)
        self.labelLetter.setAlignment(QtCore.Qt.AlignCenter)
        self.labelLetter.setObjectName("labelLetter")
        MainWindow.setCentralWidget(self.centralwidget)
        self.menubar = QtGui.QMenuBar(MainWindow)
        self.menubar.setGeometry(QtCore.QRect(0, 0, 800, 20))
        self.menubar.setObjectName("menubar")
        MainWindow.setMenuBar(self.menubar)
        self.statusbar = QtGui.QStatusBar(MainWindow)
        self.statusbar.setObjectName("statusbar")
        MainWindow.setStatusBar(self.statusbar)

        self.retranslateUi(MainWindow)

    def retranslateUi(self, MainWindow):
        MainWindow.setWindowTitle(QtGui.QApplication.translate("MainWindow", "Key Press Demo", None, QtGui.QApplication.UnicodeUTF8))
        self.labelDirections.setText(QtGui.QApplication.translate("MainWindow", "Press any key", None, QtGui.QApplication.UnicodeUTF8))
        self.labelLetter.setText(QtGui.QApplication.translate("MainWindow", "", None, QtGui.QApplication.UnicodeUTF8))

if __name__ == "__main__":
    app = QtGui.QApplication(sys.argv)
    app.processEvents()

    myapp = StartQT4()
    myapp.show()
    sys.exit(app.exec_())