python - Creating Toplevel widgets that are thread safe -

i'm trying learn how use thread module. followed along instructions here: http://effbot.org/zone/tkinter-threads.htm

my hope test script will:

1. print out "count" every 2 seconds
2. show pop-up dialog window (also every 2 seconds)
3. the pop-ups should allowed accumulate (if don't click "ok" while, there should multiple pop-ups)

however, when run script freeze main window , after while crash. think i'm not implementing thread module correctly.

could please have , point out i'm doing wrong?

here i've tried far:

from tkinter import * import thread import queue import time  class testapp:     def __init__(self, parent):         self.super_parent = parent         self.main_container = frame(parent)         self.main_container.pack()         self.top_frame = frame(self.main_container)         self.top_frame.pack(side=top)         self.bottom_frame = frame(self.main_container)         self.bottom_frame.pack(side=top)         self.text_box = text(self.top_frame)         self.text_box.config(height=20, width=20)         self.text_box.pack()         self.queue = queue.queue()         self.update_me()      def show_popup(self):         self.my_popup = toplevel(self.main_container)         self.my_popup.geometry('100x100')         self.popup_label = label(self.my_popup, text="hello!")         self.popup_label.pack(side=top)         self.pop_button = button(self.my_popup, text="ok", command=self.my_popup.destroy)         self.pop_button.pack(side=top)      def write(self, line):         self.queue.put(line)      def update_me(self):         try:             while 1:                 line = self.queue.get_nowait()                 if line none:                     self.text_box.delete(1.0, end)                 else:                     self.text_box.insert(end, str(line))                 self.text_box.see(end)                 self.text_box.update_idletasks()         except queue.empty:             pass         self.text_box.after(100, self.update_me)  def pipetowidget(input, widget):     widget.write(input)  def start_thread():     thread.start_new(start_test, (widget,))  def start_test(widget):     count = 0     while true:         pipetowidget(str(count) + "\n", widget)         count += 1         time.sleep(2)         widget.show_popup()  root = tk() widget = testapp(root) start_button = button(widget.bottom_frame, command=start_thread) start_button.configure(text="start test") start_button.pack(side=left) root.title("testing thread module") root.mainloop() 

i can't reproduce problem, can see why happen.

you're using queue pass messages background thread main thread updating text_box, correct. you're calling widget.show_popup() background thread, means creates , displays new toplevel in background thread. that's not correct.

all ui code must run in same thread—not ui code each top-level window, ui code period. on platforms, may away running each window in own thread (or free-threading everything), isn't supposed work, , crash or improper things on platforms. (also, single ui thread has initial thread on platforms, isn't relevant here.)

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so, fix this, need same dance creating popups updating textbox.

the obvious way move widget.show_popup() loop in update_me(). if want happen 2 seconds after textbox updates, add self.top_frame.after(2000, self.show_popup) method.

but i'm guessing you're trying teach how have multiple independent updating mechanisms, telling "just use single update queue everything" may not answer. in case, create 2 queues, , separate update method servicing each queue. then, pipetowidget, sleep 2 seconds, pipetopopup.

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another way around use mttkinter. you're doing, makes automatic, pushing each actual tk gui call onto queue run later main loop. of course objects have thread-safe, , means have deal gui calls 1 thread getting interleaved calls thread. long neither of problem (and don't seem in case), it's magic.

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if want know why freezing and/or crashing on win7 , not me on os x 10.8… well, need mess of tcl, c, , python code, , @ how each thing built. and, unless it's simple (like tk build isn't free-threaded), wouldn't tell anyway. code isn't supposed work, , if seems work me… means work every time until important demo of career, @ point fail.