完成功能：
1. 默认【保存】按钮enable
2. 修改文本的内容后，【enable】
3. 解决字符乱码问题：utf-8
4. 提示：如果修改了文件没有保存的时候，又尝试打开新的文件，给出相关的提示信息
操作步骤：
1. 在Designer中设计，生产**.ui文件
2. 切换到.ui文件所在目录，运行如下命令，生成.py文件
pyuic4 **.ui > **.py
# -*- 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):
response = False
# buttton texts
SAVE = 'Save'
DISCARD = 'Discard'
CANCEL = 'Cancel' # if we have changes then ask about them
if self.ui.button_save.isEnabled() and self.filename:
message = QtGui.QMessageBox(self)
message.setText('What to do about unsaved changes ?')
message.setWindowTitle('Notpad')
message.setIcon(QtGui.QMessageBox.Question)
message.addButton(SAVE, QtGui.QMessageBox.AcceptRole)
message.addButton(DISCARD, QtGui.QMessageBox.DestructiveRole)
message.addButton(CANCEL, QtGui.QMessageBox.RejectRole)
message.setDetailedText('Unsaved changes in file: '+ str(self.filename))
message.exec_()
response = message.clickedButton().text() # save file
if response == SAVE:
self.file_save()
self.ui.button_save.setEnabled(False) # descard changes
elif response == DISCARD:
self.ui.button_save.setEnabled(False) # if we didn't cancelled show the file dialogue if response != CANCEL:
''' 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)
'''文本没有被保存的时候，显示提示消息 —— 通过save是否被禁用得到文本是否被保存''' 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_())