Question

I am rather new to wx/python so please excuse if this is stupid or ill described.

I am substituting a nested sizer with a new one as shown in the snippet below. after some tinkering everything seems to work out but the re-drawing of the parent-sizer.
the content of the old nested sizer remains and gets “painted” over with the new sizer content despite my sizer.Layout()

system setup:
– python 2.5.5.2 and 2.6.4
– wxpython 2.8

# -*- coding: utf8 -*-

import wx

class Frame(wx.Frame):
def __init__(self):
    wx.Frame.__init__(self, None, wx.ID_ANY, title='test')

class Test(wx.App):
    def OnInit(self):
        frame = Frame()
        self.panel = wx.Panel(frame)
        self.panel.SetBackgroundColour('red')
        self.sizer = wx.BoxSizer(wx.VERTICAL)
        button = wx.Button(self.panel, wx.ID_ANY, 'TEST')

        self.hsizer = wx.BoxSizer(wx.HORIZONTAL)
        self.hsizer.Add(wx.StaticText(self.panel, wx.ID_ANY, 'nacknack'))

        self.sizer.Add(button)
        self.Bind(wx.EVT_BUTTON, self.on_test_button, button)
        self.text = wx.StaticText(self.panel, wx.ID_ANY, 'FOOO')
        self.sizer.Add(self.text)
        self.sizer.Add(self.hsizer)
        self.panel.SetSizer(self.sizer)
        frame.Show()
        return True

    def on_test_button(self, evt):
        tmpsizer = wx.BoxSizer(wx.VERTICAL)
        tmpsizer.Add(self.makesizer())
        tmpitem = tmpsizer.GetChildren()[0]

        self.sizer.Replace(2, tmpitem)
        self.sizer.Layout()

    def makesizer(self):
        testsizer = wx.BoxSizer(wx.HORIZONTAL)
        testsizer.Add(wx.StaticText(self.panel, wx.ID_ANY, 'testsizer'))
        return testsizer

    if __name__ == '__main__':
        app = Test()
        app.MainLoop()

Answer 1

After looking through your code (and it wasn’t easy – please consider formatting it differently next time – maybe grouping the self.sizer.add functions or something) I think I discovered your bug:

When you call Replace on a sizer, the item being replaced is not destroyed but becomes no longer managed by the sizer. You need to hide or destroy the old window (the wx.StaticText)

As mentioned in the wxWidgets docs:

virtual bool Replace (wxWindow *oldwin, wxWindow *newwin, bool recursive=false)
    Detaches the given oldwin from the sizer and replaces it with the given newwin.