CODEWITHSUNDEEP
pythonmultithreadingpython-2.7user-interfacewxpython
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Reputation: 5315

Error while creating an object of an other class in a class of type Thread in Python

Level: Beginner

I am using python v2.7 and wxPython v3.0 on windows 7 32-bit.

My app: I have 3 classes. One class is gui(wx.Frame) and other is TestThread(Thread) and the third is labels().

Problem: I am trying to create an object of the gui(wx.Frame) class in TestThread(Thread) class, but I am getting an error as given below:

Traceback (most recent call last):
  File "C:\test\post.py", line 11, in <module>
    class TestThread(Thread):
  File "C:\test\post.py", line 12, in TestThread
    guiObj = gui()
NameError: name 'gui' is not defined

However if I try to call the createPanels() of gui(wx.Frame) class from the TestThread(Thread) class like this wx.CallAfter(gui().createPanels()) then I get following error:

Exception in thread Thread-1:
Traceback (most recent call last):
  File "C:\Python27\lib\threading.py", line 810, in __bootstrap_inner
    self.run()
  File "C:\test\post.py", line 24, in run
    wx.CallAfter(gui().createPanels())
TypeError: __init__() takes exactly 4 arguments (1 given)

I think the reason is something related to the __init__() of the gui(wx.Frame) I didn't understand the reason.

Update: I tried to create an object of labels() class in TestThread(Thread) class, I get the same error as shown in first case above. Is there something special about this TestThread(Thread) class?

The complete code is provided below and can be downloaded here to avoid identation problems:

#!/usr/bin/env python

from random import randrange
import wx
import wx.lib.scrolledpanel
from threading import Thread
from wx.lib.pubsub import setuparg1
from wx.lib.pubsub import pub as Publisher
##################################################
class TestThread(Thread):
     guiObj = gui()

     def __init__(self):
        Thread.__init__(self)
        self.start()    # start the thread

     def run(self):
        wx.CallAfter(guiObj.createPanels())
        time.sleep(5)

##############################################
class gui(wx.Frame):

    def __init__(self, parent, id, title):
        screenWidth = 800
        screenHeight = 450
        screenSize = (screenWidth, screenHeight)
        wx.Frame.__init__(self, None, id, title, size=screenSize)
        self.locationFont = locationFont = wx.Font(15, wx.MODERN, wx.NORMAL, wx.BOLD)
        mainSizer = wx.BoxSizer(wx.VERTICAL)
        self.sizer = sizer = wx.BoxSizer(wx.VERTICAL)
        self.panel = panel = wx.lib.scrolledpanel.ScrolledPanel(self, -1, style=wx.SIMPLE_BORDER)
        panel.SetupScrolling()
        panel.SetBackgroundColour('#FFFFFF')
        panel.SetSizer(sizer)
        mainSizer.Add(panel, 15, wx.EXPAND|wx.ALL)
        self.SetSizer(mainSizer)

    def createPanels(self):
       k = 0
       labelObj = labels()
       locations = labelObj.getLabel()
       print locations
       for i in locations:
           sPanels = 'sPanel'+str(k)
           sPanels = wx.Panel(self.panel)
           label = str(k+1)
           text = wx.StaticText(sPanels, -1, label0)
           text.SetFont(self.locationFont)
           text.SetForegroundColour('#0101DF')
           self.sizer.Add(sPanels, 0, wx.ALL, 5)
           self.sizer.Add(wx.StaticLine(self.panel), 0, wx.ALL|wx.EXPAND, 0)
           k += 1

   TestThread()
################################################
class labels():
    def getLabel(self):
       mylist =[]
       i = randrange(10)
       for k in range(1,i+1):
           mylist.append(k)
       return mylist
###############################################

if __name__=='__main__':
   app = wx.App()
   frame = gui(parent=None, id=-1, title="Test")
   frame.Show()
   app.MainLoop()

Thank you for your time!

Upvotes: 0

Views: 76

Answers (1)

Valentin Lorentz
Valentin Lorentz

Reputation: 9753

For the first issue:

guiObj = gui() is executed when Python first runs the file, which causes two problems:

  • Python does not know about gui when executing it
  • All instances of TestThread will have the same gui instance

To fix both of them, you have to put guiObj = gui() in the constructor of TestThread

If you only want to fix the first one, put the declaration of gui before the declaration of TestThread.

For the second issue:

Using gui() is wrong because the constructor of gui takes three arguments (four actually, but the first one is implicit. You have to call it with three arguments, like you did at the end of the program: gui(parent=None, id=-1, title="Test")

Upvotes: 1

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