2

I am trying to create a window that receives simple event notifications from a Process. Here is the code that I have so far:

import wx, wx.lib.newevent, time, sys
from multiprocessing import Process

size_width = 320
size_height = 240
background_color = (226,223,206)

SomeNewEvent, EVT_SOME_NEW_EVENT = wx.lib.newevent.NewEvent()


class StatusWindow(wx.Frame):
    def __init__(self, parent):
        super(StatusWindow, self).__init__(parent, title='Monitor', size=(size_width, size_height))

        self.Bind(EVT_SOME_NEW_EVENT, self.updateStatus)

        staticBox = wx.StaticBox(self, label='Monitor Status:', pos=(5, 105), size=(size_width - 28, size_height/3))
        self.statusLabel = wx.StaticText(staticBox, label='None', pos=(10, 35), size=(size_width, 20), style=wx.ALIGN_LEFT)
        self.count = 0
        self.InitUI()

        self.monitor = cMonitor()
        self.monitor.start()

    def InitUI(self):
        panel = wx.Panel(self)    
        self.SetBackgroundColour(background_color)
        self.Centre()
        self.Show()

    def updateStatus(self, evt):
        self.statusLabel.SetLabel(evt.attr1)

class cMonitor(Process):
    def __init__(self):
        super(cMonitor, self).__init__()

    def run(self):
        time.sleep(2)
        print 'This is an update'
        #create the event
        evt = SomeNewEvent(attr1="Some event has just occured")
        #post the event
        wx.PostEvent(EVT_SOME_NEW_EVENT, evt)

if __name__ == '__main__':
    app = wx.App()
    window = StatusWindow(None)
    app.MainLoop()

The window gets created, but the Process does not appear to be either executing or sending the post event notification correctly. I should note that the print statement in the run method is not showing up either. What is causing the GUI to not be updated?? This was what I used as a reference:

http://wiki.wxpython.org/CustomEventClasses

1
  • I'm getting a fatal IO error 11 when I run this code on Linux. Full error log here: pastebin.com/ggvELbMY Commented Sep 8, 2014 at 13:38

1 Answer 1

1

First of all, your code throws an error:

Traceback (most recent call last):
  File "C:\Python27\lib\multiprocessing\process.py", line 232, in _bootstrap
    self.run()
  File "C:\PyProgs\stackoverflow_answers\wx_answers\wx_events1.py", line 44, in run
    wx.PostEvent(EVT_SOME_NEW_EVENT, evt)
  File "C:\Python27\lib\site-packages\wx-3.0-msw\wx\_core.py", line 8410, in PostEvent
    return _core_.PostEvent(*args, **kwargs)
TypeError: in method 'PostEvent', expected argument 1 of type 'wxEvtHandler *'

According the docs, PostEvent(dest, event) send an event to a window or other wx.EvtHandler to be processed later, but in your code first parameter has type PyEventBinder. Your code would have to look something like this:

wx.PostEvent(self.wxWindow, evt)

where self.wxWindow - object of StatusWindow class. But there is another problem: you can not use wxPython objects as multiprocessor arguments(link).

One way to do what you want - using threading module instead multiprocessing:

import wx, wx.lib.newevent, time, sys
from threading import *
size_width = 320
size_height = 240
background_color = (226,223,206)

SomeNewEvent, EVT_SOME_NEW_EVENT = wx.lib.newevent.NewEvent()


class StatusWindow(wx.Frame):
    def __init__(self, parent):
        super(StatusWindow, self).__init__(parent, title='Monitor', size=(size_width, size_height))

        self.Bind(EVT_SOME_NEW_EVENT, self.updateStatus)

        staticBox = wx.StaticBox(self, label='Monitor Status:', pos=(5, 105), size=(size_width - 28, size_height/3))
        self.statusLabel = wx.StaticText(staticBox, label='None', pos=(10, 35), size=(size_width, 20), style=wx.ALIGN_LEFT)
        self.count = 0
        self.InitUI()

        # Set up event handler for any worker thread results
        self.monitor = cMonitor(self)
        self.monitor.start()

    def InitUI(self):
        panel = wx.Panel(self)    
        self.SetBackgroundColour(background_color)
        self.Centre()
        self.Show()

    def updateStatus(self, evt):
        self.statusLabel.SetLabel(evt.attr1)



class cMonitor(Thread):
    def __init__(self, wxWindow):
        super(cMonitor, self).__init__()
        self.wxWindow = wxWindow


    def run(self):
        time.sleep(2)
        print 'This is an update'
        #create the event
        evt = SomeNewEvent(attr1="Some event has just occured")
        #post the event
        wx.PostEvent(self.wxWindow, evt)

if __name__ == '__main__':

    app = wx.App()
    window = StatusWindow(None)
    app.MainLoop()
Sign up to request clarification or add additional context in comments.

Comments

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Start asking to get answers

Find the answer to your question by asking.

Ask question

Explore related questions

See similar questions with these tags.