重定向wxPython程序的输出

#!/usr/bin/env python
import wx
import sys
class Frame(wx.Frame):
	def __init__(self, parent, id, title):
		print "Frame __init__"
		wx.Frame.__init__(self, parent, id, title)
		
class App(wx.App):
	
	
	def __init__(self, redirect = True, filename = None):
		print "App __init__"
		wx.App.__init__(self, redirect, filename)
		
	def OnInit(self):
		print "OnInit"
		self.frame = Frame(parent = None, id = -1, title = "Startup")
		self.frame.Show()
		self.SetTopWindow(self.frame)
		print >> sys.stderr, "A pretend error message"
		return True
		
	# after the last window closes but before wxPython’s internal cleanup.
	# normal shutdown
	#   wx.App.OnExit()
	#   Even if the application is closed with wx.Exit(), the OnExit() method is still triggered.
	# emergency shutdown
	#   1. wx.App.ExitMainLoop()
	#   2. wx.Exit()
	def OnExit(self):
		print "OnExit"

if __name__ == "__main__":
	# if redirect == True
	#   a console frame will display message
	# if redirect == True
    #   filename can point to a local system file for recording message.
	app = App(redirect = True, filename = "listing2.1output.txt")
	print "before MainLoop"
	app.MainLoop()
	print "aflter Main Loop"