CenterTest.py

#!/usr/bin/env python

import wx

class MyPanel(wx.Panel):
 def __init__(self, parent):
 wx.Panel.__init__(self, parent, -1)

 b = wx.Button(self, -1, "Hello")
 b.Bind(wx.EVT_BUTTON, self.OnClick)
 # the Bind() method removes the need to keep track of IDs

 Sizer = wx.BoxSizer(wx.VERTICAL)
 ## by adding a stretchable spacer above and below, you get the
 ## button centered.
 Sizer.Add((1,1), 1) ## this adds a 1X1 pixel spacer
 ## but the "1" means that it has a stretch factor of 1
 Sizer.Add(b, 0, wx.ALIGN_CENTER) # the "0" means it won't stretch
 Sizer.Add((1,1), 2) # same as above
 # try changing the stretch factors, and see what you get.

 self.SetSizer(Sizer)

 def OnClick(self, event):
 msgdialog = wx.MessageDialog(self,"HELLO WHIRLED",style=wx.OK)
 msgdialog.ShowModal()

class MyFrame(wx.Frame):
 def __init__(self, parent=None, id=-1, title='Wombat',
 pos=wx.DefaultPosition, size=(200, 200)):
 wx.Frame.__init__(self, parent, id, title, pos, size)
 panel = MyPanel(self)

class App(wx.App):
 def OnInit(self):
 frame = MyFrame()
 frame.Center()
 frame.Show()
 self.SetTopWindow(frame)
 return True

def main():
 app = App()
 app.MainLoop()

if __name__ == '__main__':
 main()