pyqt5 打开文件

import sys
import os
from PyQt5.QtCore import *
from PyQt5.QtWidgets import *

class Notepad(QMainWindow):
def __init__(self):
super().__init__()
self.initUI()

def initUI(self):
openAction = QAction('Open', self)
openAction.setShortcut('Ctrl+O')
openAction.setStatusTip('Open a file')
openAction.triggered.connect(self.openFile)

closeAction = QAction('Close', self)
closeAction.setShortcut('Ctrl+Q')
closeAction.setStatusTip('Close Notepad')
closeAction.triggered.connect(self.close)

menubar = self.menuBar()
fileMenu = menubar.addMenu('&File')
fileMenu.addAction(openAction)
fileMenu.addAction(closeAction)

self.textEdit = QTextEdit(self)
self.textEdit.setFocus()
self.textEdit.setReadOnly(True)

self.resize(700, 800)
self.setWindowTitle('Notepad')
self.setCentralWidget(self.textEdit)
self.show()

def openFile(self):
filename, _ = QFileDialog.getOpenFileName(self, 'Open File', os.getenv('HOME'))

fh = ''

if QFile.exists(filename):
fh = QFile(filename)

if not fh.open(QFile.ReadOnly):
QtGui.qApp.quit()

data = fh.readAll()
codec = QTextCodec.codecForUtfText(data)
unistr = codec.toUnicode(data)

tmp = ('Notepad: %s' % filename)
self.setWindowTitle(tmp)

self.textEdit.setText(unistr)

def main():
app = QApplication(sys.argv)
notepad = Notepad()
sys.exit(app.exec_())

if __name__ == '__main__':
main()