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Thread: How to update GUI from a thread?

  1. #1
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    Feb 2021
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    Default How to update GUI from a thread?

    I'm trying to update the QLabel in the GUI with the number, generated in a thread. Can this be done?

    Qt Code:
    1. import threading, random, sys
    2. from PyQt5.QtWidgets import *
    3. from PyQt5.QtGui import *
    4. from PyQt5.QtCore import *
    5. from PyQt5 import QtCore, QtTest
    6.  
    7.  
    8. def update():
    9. while True:
    10. n = random.randint(0,22)
    11. QtTest.QTest.qWait(500)
    12.  
    13. threading.Thread(target=update, daemon = True).start()
    14.  
    15. class MainWindow(QMainWindow):
    16.  
    17. def __init__(self, *args, **kwargs):
    18. super(MainWindow, self).__init__(*args, **kwargs)
    19. self.setFixedSize(200, 200)
    20.  
    21. self.labl = QLabel(self)
    22. self.labl.setText("value of n goes here")
    23.  
    24.  
    25. app = QApplication(sys.argv)
    26. window = MainWindow()
    27. window.show()
    28. sys.exit(app.exec_())
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  2. #2
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    Default Re: How to update GUI from a thread?

    The usual way is to have your thread emit a signal that is handled by a slot in the your GUI thread, where you pass the value as an argument in the signal.

    This also means you probably need to use QThread for your thread implementation.
    <=== The Great Pumpkin says ===>
    Please use CODE tags when posting source code so it is more readable. Click "Go Advanced" and then the "#" icon to insert the tags. Paste your code between them.

  3. The following user says thank you to d_stranz for this useful post:

    kiskivancsi (7th February 2021)

  4. #3
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    Default Re: How to update GUI from a thread?

    Have same problem

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