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    <p>here, try this:</p> <pre><code>from Tkinter import * import time root=Tk() variable=StringVar() def update_label(): i=0 while 1: i=i+1 variable.set(str(i)) root.update() your_label=Label(root,textvariable=variable) your_label.pack() start_button=Button(root,text="start",command=update_label) start_button.pack() root.mainloop() </code></pre> <p>That should give you a good example. However, it is important to note that during the while loop, you MUST call <code>root.update()</code> otherwise your GUI will freeze until the loop completes (in this case it <em>never</em> does) and never show your numbers.</p> <p>Also note that you <em>can</em> call <code>update_label()</code> from anywhere in your program. I just added it to the start button for example purposes.</p> <p>What was wrong with your code was that you had set the while loop free-floating and most importantly <em>before</em> your GUI's mainloop. When you do this, since this loop is infinate, it never allows <code>Tkinter</code> to start its <code>mainloop()</code>. However, if you were to put the while loop <em>after</em> the mainloop, then that would never be executed until <em>after</em> you exit the GUI, this is because the mainloop is infinate until it is stopped (closing the GUI).</p> <p>So to fix this you simply put it in a function and call it later on during <code>Tkinter</code>'s mainloop. You can do this various ways as well, for example, you can use <code>.after()</code> to perform a specific task after a certain amount of time, or make it the command of a button to be run when pressed, ect., ect. .</p> <p>However, The <em>proper</em> code you should use is the following, as you do not really want infinate loops in your code (other then you mainloop).:</p> <pre><code>class App (object): def __init__(self): self.root=Tk() self.variable=StringVar() self.i=0 self.your_label=Label(self.root,textvariable=self.variable) def grid(self): self.your_label.pack() def update_label(self): self.i=self.i+1 self.variable.set(str(self.i)) self.root.after(20,self.update_label) def run(self): self.grid() self.root.after(20,self.update_label) self.root.mainloop() if __name__=='__main__': App().run() </code></pre>
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    1. CO-1: you should never call sleep in the main thread of a GUI. Doing so in an answer sets a bad example. You are wrong when you say that by calling `update` this never freezes. While the sleep is active, the UI _will_ be frozen, even if only for half a second.
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    2. CO@BryanOakley Ok i changed that.
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    3. COIt's still not the right solution. In addition to not calling `sleep`, as a rule of thumb you shouldn't have infinite loops either. To update a label every half second you should take advantage of the event loop and use `after`
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