Label in PyQt4 GUI not updating with every loop of FOR loop

Posted by user297920 on Stack Overflow See other posts from Stack Overflow or by user297920
Published on 2010-03-20T08:45:13Z Indexed on 2010/03/20 8:51 UTC
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I'm having a problem, where I wish to run several command line functions from a python program using a GUI. I don't know if my problem is specific to PyQt4 or if it has to do with my bad use of python code.

What I wish to do is have a label on my GUI change its text value to inform the user which command is being executed. My problem however, arises when I run several commands using a for loop. I would like the label to update itself with every loop, however, the program is not updating the GUI label with every loop, instead, it only updates itself once the entire loop is completed, and displays only the last command that was executed.

I am using PyQt4 for my GUI environment. And I have established that the text variable for the label is indeed being updated with every loop, but, it is not actually showing up visually in the GUI.

Is there a way for me to force the label to update itself? I have tried the update() and repaint() methods within the loop, but they don't make any difference.

I would really appreciate any help. Thank you.

Ronny.

Here is the code I am using:

# -*- coding: utf-8 -*-
import sys, os
from PyQt4 import QtGui, QtCore
Gui = QtGui
Core = QtCore

# ================================================== CREATE WINDOW OBJECT CLASS
class Win(Gui.QWidget):
    def __init__(self, parent = None):
        Gui.QWidget.__init__(self, parent)

        # --------------------------------------------------- SETUP PLAY BUTTON
        self.but1 = Gui.QPushButton("Run Commands",self)
        self.but1.setGeometry(10,10, 200, 100)

        # -------------------------------------------------------- SETUP LABELS
        self.label1 = Gui.QLabel("No Commands running", self)
        self.label1.move(10, 120)

        # ------------------------------------------------------- SETUP ACTIONS
        self.connect(self.but1, Core.SIGNAL("clicked()"), runCommands)


# =======================================================  RUN COMMAND FUNCTION
def runCommands():
    for i in commands:
        win.label1.setText(i)       # Make label display the command being run
        print win.label1.text()     # This shows that the value is actually
                                    # changing with every loop, but its just not
                                    # being reflected in the GUI label
        os.system(i)

# ======================================================================== MAIN

# ------------------------------------------------------  THE TERMINAL COMMANDS
com1 = "espeak 'senntence 1'"
com2 = "espeak 'senntence 2'"
com3 = "espeak 'senntence 3'"
com4 = "espeak 'senntence 4'"
com5 = "espeak 'senntence 5'"
commands = (com1, com2, com3, com4, com5)

# --------------------------------------------------- SETUP THE GUI ENVIRONMENT
app = Gui.QApplication(sys.argv)
win = Win()
win.show()

sys.exit(app.exec_())

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