Added the sample code from wxPython In Action to the samples dir

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@42925 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

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

@@ -0,0 +1,101 @@
+import wx
+import threading
+import random
+
+class WorkerThread(threading.Thread):
+    """
+    This just simulates some long-running task that periodically sends
+    a message to the GUI thread.
+    """
+    def __init__(self, threadNum, window):
+        threading.Thread.__init__(self)
+        self.threadNum = threadNum
+        self.window = window
+        self.timeToQuit = threading.Event()
+        self.timeToQuit.clear()
+        self.messageCount = random.randint(10,20)
+        self.messageDelay = 0.1 + 2.0 * random.random()
+
+    def stop(self):
+        self.timeToQuit.set()
+
+    def run(self):
+        msg = "Thread %d iterating %d times with a delay of %1.4f\n" \
+              % (self.threadNum, self.messageCount, self.messageDelay)
+        wx.CallAfter(self.window.LogMessage, msg)
+
+        for i in range(1, self.messageCount+1):
+            self.timeToQuit.wait(self.messageDelay)
+            if self.timeToQuit.isSet():
+                break
+            msg = "Message %d from thread %d\n" % (i, self.threadNum)
+            wx.CallAfter(self.window.LogMessage, msg)
+        else:
+            wx.CallAfter(self.window.ThreadFinished, self)
+            
+            
+
+class MyFrame(wx.Frame):
+    def __init__(self):
+        wx.Frame.__init__(self, None, title="Multi-threaded GUI")
+        self.threads = []
+        self.count = 0
+        
+        panel = wx.Panel(self)
+        startBtn = wx.Button(panel, -1, "Start a thread")
+        stopBtn  = wx.Button(panel, -1, "Stop all threads")
+        self.tc = wx.StaticText(panel, -1, "Worker Threads: 00")
+        self.log = wx.TextCtrl(panel, -1, "",
+                               style=wx.TE_RICH|wx.TE_MULTILINE)
+
+        inner = wx.BoxSizer(wx.HORIZONTAL)
+        inner.Add(startBtn, 0, wx.RIGHT, 15)
+        inner.Add(stopBtn, 0, wx.RIGHT, 15)
+        inner.Add(self.tc, 0, wx.ALIGN_CENTER_VERTICAL)
+        main = wx.BoxSizer(wx.VERTICAL)
+        main.Add(inner, 0, wx.ALL, 5)
+        main.Add(self.log, 1, wx.EXPAND|wx.ALL, 5)
+        panel.SetSizer(main)
+
+        self.Bind(wx.EVT_BUTTON, self.OnStartButton, startBtn)
+        self.Bind(wx.EVT_BUTTON, self.OnStopButton, stopBtn)
+        self.Bind(wx.EVT_CLOSE,  self.OnCloseWindow)
+
+        self.UpdateCount()
+
+    def OnStartButton(self, evt):
+        self.count += 1
+        thread = WorkerThread(self.count, self)
+        self.threads.append(thread)
+        self.UpdateCount()
+        thread.start()
+    
+    def OnStopButton(self, evt):
+        self.StopThreads()
+        self.UpdateCount()
+        
+    def OnCloseWindow(self, evt):
+        self.StopThreads()
+        self.Destroy()
+
+    def StopThreads(self):
+        while self.threads:
+            thread = self.threads[0]
+            thread.stop()
+            self.threads.remove(thread)
+            
+    def UpdateCount(self):
+        self.tc.SetLabel("Worker Threads: %d" % len(self.threads))
+        
+    def LogMessage(self, msg):
+        self.log.AppendText(msg)
+        
+    def ThreadFinished(self, thread):
+        self.threads.remove(thread)
+        self.UpdateCount()
+        
+
+app = wx.PySimpleApp()
+frm = MyFrame()
+frm.Show()
+app.MainLoop()