wxPython/samples/wxPIA_book/Chapter-18/worker_threads.py

   1 import wx
   2 import threading
   3 import random
   4
   5 class WorkerThread(threading.Thread):
   6     """
   7     This just simulates some long-running task that periodically sends
   8     a message to the GUI thread.
   9     """
  10     def __init__(self, threadNum, window):
  11         threading.Thread.__init__(self)
  12         self.threadNum = threadNum
  13         self.window = window
  14         self.timeToQuit = threading.Event()
  15         self.timeToQuit.clear()
  16         self.messageCount = random.randint(10,20)
  17         self.messageDelay = 0.1 + 2.0 * random.random()
  18
  19     def stop(self):
  20         self.timeToQuit.set()
  21
  22     def run(self):
  23         msg = "Thread %d iterating %d times with a delay of %1.4f\n" \
  24               % (self.threadNum, self.messageCount, self.messageDelay)
  25         wx.CallAfter(self.window.LogMessage, msg)
  26
  27         for i in range(1, self.messageCount+1):
  28             self.timeToQuit.wait(self.messageDelay)
  29             if self.timeToQuit.isSet():
  30                 break
  31             msg = "Message %d from thread %d\n" % (i, self.threadNum)
  32             wx.CallAfter(self.window.LogMessage, msg)
  33         else:
  34             wx.CallAfter(self.window.ThreadFinished, self)
  35
  36
  37
  38 class MyFrame(wx.Frame):
  39     def __init__(self):
  40         wx.Frame.__init__(self, None, title="Multi-threaded GUI")
  41         self.threads = []
  42         self.count = 0
  43
  44         panel = wx.Panel(self)
  45         startBtn = wx.Button(panel, -1, "Start a thread")
  46         stopBtn  = wx.Button(panel, -1, "Stop all threads")
  47         self.tc = wx.StaticText(panel, -1, "Worker Threads: 00")
  48         self.log = wx.TextCtrl(panel, -1, "",
  49                                style=wx.TE_RICH|wx.TE_MULTILINE)
  50
  51         inner = wx.BoxSizer(wx.HORIZONTAL)
  52         inner.Add(startBtn, 0, wx.RIGHT, 15)
  53         inner.Add(stopBtn, 0, wx.RIGHT, 15)
  54         inner.Add(self.tc, 0, wx.ALIGN_CENTER_VERTICAL)
  55         main = wx.BoxSizer(wx.VERTICAL)
  56         main.Add(inner, 0, wx.ALL, 5)
  57         main.Add(self.log, 1, wx.EXPAND|wx.ALL, 5)
  58         panel.SetSizer(main)
  59
  60         self.Bind(wx.EVT_BUTTON, self.OnStartButton, startBtn)
  61         self.Bind(wx.EVT_BUTTON, self.OnStopButton, stopBtn)
  62         self.Bind(wx.EVT_CLOSE,  self.OnCloseWindow)
  63
  64         self.UpdateCount()
  65
  66     def OnStartButton(self, evt):
  67         self.count += 1
  68         thread = WorkerThread(self.count, self)
  69         self.threads.append(thread)
  70         self.UpdateCount()
  71         thread.start()
  72
  73     def OnStopButton(self, evt):
  74         self.StopThreads()
  75         self.UpdateCount()
  76
  77     def OnCloseWindow(self, evt):
  78         self.StopThreads()
  79         self.Destroy()
  80
  81     def StopThreads(self):
  82         while self.threads:
  83             thread = self.threads[0]
  84             thread.stop()
  85             self.threads.remove(thread)
  86
  87     def UpdateCount(self):
  88         self.tc.SetLabel("Worker Threads: %d" % len(self.threads))
  89
  90     def LogMessage(self, msg):
  91         self.log.AppendText(msg)
  92
  93     def ThreadFinished(self, thread):
  94         self.threads.remove(thread)
  95         self.UpdateCount()
  96
  97
  98 app = wx.PySimpleApp()
  99 frm = MyFrame()
 100 frm.Show()
 101 app.MainLoop()