莫非at不能定时执行图形程序？

想趁晚上没有人使用网路时用amule下载一些东西，却发现使用at并不能定时执行图形化的程序，而定时执行console程序是没有问题的，man了一下又google了半天没有任何收获，只得用python临时写一个简单的先凑合用着（下载）。

#!/usr/bin/python
#coding=UTF-8

import wx
import os

class MyApp(wx.App):
 def OnInit(self):
 self.frame = wx.Frame(None,-1,"RunAt",size=(290,77))

self.lblCmd = wx.StaticText(self.frame,-1,"命令：")
 self.txtCmd = wx.TextCtrl(self.frame,-1,size=(150,-1))
 self.btnSelect = wx.Button(self.frame,-1,"选择")
 self.btnSelect.Bind(wx.EVT_BUTTON,self.Select)

self.lblTime = wx.StaticText(self.frame,-1,"时间：")
 self.txtTime = wx.TextCtrl(self.frame,-1,size=(150,-1))
 self.btnSet = wx.Button(self.frame,-1,"设定")
 self.btnSet.Bind(wx.EVT_BUTTON,self.Set)

sizer1 = wx.BoxSizer(wx.HORIZONTAL)
 sizer1.Add(self.lblCmd,0,wx.LEFT|wx.TOP|wx.ALIGN_CENTER,5)
 sizer1.Add(self.txtCmd,0,wx.LEFT|wx.TOP|wx.ALIGN_CENTER,5)
 sizer1.Add(self.btnSelect,0,wx.LEFT|wx.TOP|wx.ALIGN_CENTER,5)

sizer2 = wx.BoxSizer(wx.HORIZONTAL)
 sizer2.Add(self.lblTime,0,wx.LEFT|wx.TOP|wx.ALIGN_CENTER,5)
 sizer2.Add(self.txtTime,0,wx.LEFT|wx.TOP|wx.ALIGN_CENTER,5)
 sizer2.Add(self.btnSet,0,wx.LEFT|wx.TOP|wx.ALIGN_CENTER,5)

sizer = wx.BoxSizer(wx.VERTICAL)
 sizer.Add(sizer1,0)
 sizer.Add(sizer2,0)

self.frame.SetSizer(sizer)

self.runTime = None

self.timer = wx.Timer()
 self.timer.Bind(wx.EVT_TIMER,self.OnTimer)
 self.timer.Start()

self.frame.Bind(wx.EVT_ICONIZE,self.OnMin)

self.frame.Center()
 self.frame.Show(True)
 self.SetTopWindow(self.frame)

return True

def Select(self,event):
 dlg = wx.FileDialog(self.frame)
 if dlg.ShowModal() == wx.ID_OK:
 self.txtCmd.SetValue(dlg.GetPath())

def OnTimer(self,event):
 if self.runTime == None:
 pass
 t = wx.DateTime.Now()
 str = "%02d:%02d" %(t.GetHour(),t.GetMinute())
 if str == self.runTime and t.GetSecond() == 0:
 os.system("%s&" %self.txtCmd.GetValue())

def Set(self,event):
 self.runTime = self.txtTime.GetValue()

def OnMin(self,event):
 self.frame.Show(False)

def main():
 app = MyApp(0)
 app.MainLoop()

if __name__ == "__main__":
 main()