pyqt重写键盘事件+获取信号发送对象

# _*_ coding:utf-8 _*_
import sys
from PyQt4 import QtGui,QtCore

class Example(QtGui.QMainWindow):
    def __init__(self):
        super(Example,self).__init__()
        self.setWindowTitle('Escape')
        self.initUI()
        self.resize(250,150)
    def initUI(self):
        button1=QtGui.QPushButton('button1',self)
        button2=QtGui.QPushButton('button2',self)
        button1.move(30,30)
        button2.move(30,100)

        self.connect(button1,QtCore.SIGNAL('clicked()'),self.buttonClicked)
        self.connect(button2, QtCore.SIGNAL('clicked()'), self.buttonClicked)
        self.statusBar().showMessage('Ready')
    def buttonClicked(self):
        sender=self.sender()
        self.statusBar().showMessage(sender.text()+'was pressed')

    def  keyPressEvent(self,event):
        print event.key()
        print QtCore.Qt.Key_Escape
        if event.key()==QtCore.Qt.Key_Enter:
            self.close()
app=QtGui.QApplication(sys.argv)
ex=Example()
ex.show()
sys.exit(app.exec_())