[pygtk] Add gtk threading example, bug 461551

[John Stowers <jstowers src gnome org>]

commit 5eea5d244e7a69b517f08506e8c1950fb721d6f9
Author: Dieter Verfaillie <dieterv optionexplicit be>
Date:   Fri Dec 24 00:43:15 2010 +1300

    Add gtk threading example, bug 461551

 examples/threading/gtk_threading.py |  100 +++++++++++++++++++++++++++++++++++
 1 files changed, 100 insertions(+), 0 deletions(-)
---
diff --git a/examples/threading/gtk_threading.py b/examples/threading/gtk_threading.py
new file mode 100644
index 0000000..452b81f
--- /dev/null
+++ b/examples/threading/gtk_threading.py
@@ -0,0 +1,100 @@
+#!/usr/bin/env python
+
+
+import time
+import threading
+
+import gtk
+import gobject
+
+
+def identify(message):
+    t = threading.current_thread()
+    print t.name, message
+
+
+class WorkerThread(threading.Thread):
+    def __init__(self, window):
+        identify('Initializing new thread')
+
+        threading.Thread.__init__(self)
+        self.window = window
+
+    def run(self):
+        identify('Doing work in new thread')
+
+        for i in range(10):
+            # Let's do some hard work here
+            time.sleep(0.5)
+
+            # let the window know we did something
+            gobject.idle_add(self.window.worker_update, 'Doing hard work: %s' % str(i+1))
+
+            # and update the progressbar
+            fraction = (i + 1) / float(10)
+            gobject.idle_add(self.window.progress.set_fraction, fraction)
+
+        # We're done
+        gobject.idle_add(self.window.worker_join)
+
+
+class TestWindow(gtk.Window):
+    __gtype_name = 'TestWindow'
+
+    def __init__(self):
+        gtk.Window.__init__(self)
+        self.set_border_width(4)
+        self.connect('delete-event', self.on_delete_event)
+        self.working = False
+
+        self.vbox = gtk.VBox(spacing=4)
+        self.add(self.vbox)
+
+        self.progress = gtk.ProgressBar()
+        self.vbox.pack_start(self.progress)
+
+        self.label = gtk.Label()
+        self.vbox.pack_start(self.label)
+
+        self.button = gtk.Button('start thread')
+        self.button.connect('clicked', self.button_clicked)
+        self.vbox.pack_start(self.button)
+
+    def on_delete_event(self, widget, event):
+        if self.working:
+            # do not close this window now, we'e working!
+            return True
+        else:
+            return False
+
+    def button_clicked(self, button):
+        self.button.set_sensitive(False)
+        self.worker_start()
+
+    def worker_start(self):
+        self.working = True
+        self.worker = WorkerThread(self)
+        self.worker.start()
+
+    def worker_update(self, value):
+        t = threading.current_thread()
+        print t.name, 'Updating label'
+        self.label.set_text(value)
+
+    def worker_join(self):
+        self.worker.join()
+        self.button.set_sensitive(True)
+        self.label.set_text('Done!')
+        self.working = False
+
+
+if __name__ == '__main__':
+    gobject.threads_init()
+
+    testwindow = TestWindow()
+    testwindow.connect('delete-event', gtk.main_quit)
+    testwindow.show_all()
+
+    gtk.main()
+
+