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Thread: Thread Issue: Unable to update UI

  1. #1
    Join Date
    Mar 2014
    Posts
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    Qt products
    Qt4 Qt5 Qt/Embedded
    Platforms
    Unix/X11 Windows

    Default Thread Issue: Unable to update UI

    Hi,
    I am developing an Qt application.
    It has one loop which keep on running for long time and at the same time i want to update the value in Ui.
    Whats happening in my case is UI become unresponsive for some time.

    I have created a background thread and running the loop in that thread but it seems that only this thread is running and result is not updated in UI. Only final value of loop is printed in Ui.
    Eg if loop runs 7000 times then only 7000 is displayed in UI, rest of values are not displayed.

    Code :
    Qt Code:
    1. class bgthread :Qthread
    2. {
    3. run()
    4. {
    5. loopFunction()
    6. }
    7. }
    8.  
    9. loopfunction()
    10. {
    11. emit valuechanged(i);
    12. }
    13.  
    14.  
    15. class guiCreate:Qmainwindow
    16. {
    17. connect(bgThread,SIGNAL(valuechanged(int)),this,SLOT(updateui(int)));
    18.  
    19. }
    20.  
    21. guiCreate::updateui(int i)
    22. {
    23. iterationQLabel->setText(QString::number(i));
    24. }
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    Last edited by anda_skoa; 27th May 2014 at 18:45. Reason: missing [code] tags

  2. #2
    Join Date
    Jan 2006
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    Qt products
    Qt3 Qt4 Qt5
    Platforms
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    Default Re: Thread Issue: Unable to update UI

    Paste some actual code and use code tags.

    Cheers,
    _

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