Why time.sleep and after freeze whole Python program?

Question

0.00/5 (No votes)

See more:

In my python program using TKinter, the function "code04" calls printIt04 and that function prints something each time and waits for 0.2 seconds. but when "code04" called, the whole app freezes and then all of the text will be printed once. How can I solve it?

What I have tried:

Python

	def code04(self):
		w = len(self.Matrix[0])
		for x in range(0, 8):
			self.printIt04(w, x)

.
.
.
	def printIt04(self, w, x):
		if (w > 200):
			MStartCol = int(round( (w - 200)/2))
			MEndCol = 200 + MStartCol
			IStartCol = 0
			IEndCol = 200
		else:
			MStartCol = 0
			MEndCol = w
			IStartCol = int(round( (200 - w)/2))
			IEndCol = IStartCol + w
		r = int(round( (w - 200)/2))
		for col in range(MStartCol, MEndCol):
			for row in range(0, x+1):
				if self.Matrix[7-row][col] == 1:
					self.img.put ("#ff0000", ( IStartCol - MStartCol + col, 7-row))
				else:
					self.img.put ("#000000", ( IStartCol - MStartCol + col, 7-row))
		time.sleep(0.2)

Posted 26-Jun-16 6:24am

Ali-RNT

Updated 26-Jun-16 7:23am

Add a Solution

Comments

Sergey Alexandrovich Kryukov 26-Jun-16 16:41pm

I cannot imagine a single valid case of using sleep in UI thread. Why?
—SA

1 solution

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Dave Kreskowiak · Accepted Answer · 2016-06-26T07:23:00

The reason it does this is because all of your code is running on the startup thread, otherwise known as the "UI thread". Your code is hogging the thread, stopping it from receiving and processing the WM_PAINT messages the thread is getting. Until your code returns and the thread goes back to idle, these paint messages will just queue up. When you finally give up control all the queued message get processed and the window gets repainted showing you the end result.

You either have to use a timer to "tick" through your loop or move all of the "work" to a background thread freeing up the UI thread to process the messages.