PyQt4 模拟记事本基本功能（保存，打开文件）

# -*- coding: utf-8 -*-
import sys
from PyQt4 import QtCore, QtGui
from edytor import Ui_notepad
from os.path import isfile
import codecs

class StartQt4(QtGui.QMainWindow):
    def __init__(self, parent=None, flags=0):
        QtGui.QWidget.__init__(self, parent)
        self.ui = Ui_notepad()
        self.ui.setupUi(self)
        ‘‘‘ click点击 button_open 执行file_dialog‘‘‘
        QtCore.QObject.connect(self.ui.button_open, QtCore.SIGNAL("clicked()"), self.file_dialog)
        ‘‘‘ click点击 button_save 执行file_save保存‘‘‘
        QtCore.QObject.connect(self.ui.button_save, QtCore.SIGNAL("clicked()"), self.file_save)
        ‘‘‘ editor_window的内容发送改变时，执行enable_save函数，enable = true‘‘‘
        QtCore.QObject.connect(self.ui.editor_window, QtCore.SIGNAL("textChanged()"),self.enable_save )
        
    def file_dialog(self):
        ‘‘‘ 使用QFileDialog来选择文件‘‘‘
        fd = QtGui.QFileDialog(self) 
        ‘‘‘ 使用getOpenFileName()弹出一个文件选择框
        fd.getOpenFileName()用于返回我们选择文件的名字。如果没有选择文件的话，会得打一个空的文件名
        ‘‘‘
        self.filename = fd.getOpenFileName()
        if isfile(self.filename):
            text = codecs.open(self.filename, ‘r‘, ‘utf-8‘).read()
            self.ui.editor_window.setPlainText(text)    
            self.ui.button_save.setEnabled(False)
                  
    def file_save(self):
        if isfile(self.filename):
            file = codecs.open(self.filename, ‘w‘, ‘utf-8‘)
            file.write(unicode(self.ui.editor_window.toPlainText()))
            file.close()  
            self.ui.button_save.setEnabled(False)
           
    def enable_save(self):
        self.ui.button_save.setEnabled(True)
        
           
if __name__ == "__main__":
     app = QtGui.QApplication(sys.argv)
     myapp = StartQt4()
     myapp.show()
     sys.exit(app.exec_())