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Thread: Update GUI before lengthy task

  1. #1
    Junior Member
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    Default Update GUI before lengthy task

    I'm trying to change a GUI element before preforming a lengthy function (little icon to show its busy), but I'm not too sure how to do it.

    If I make the change then start the task, GUI doesn't update until the function is finished.
    I can make the GUI changes then start the task in a new thread, but I want to lock all user input too, and disabling every component seems a bit tedious.

    So far, the most promising solution seems to be:
    1) change GUI
    2) set flag indicating long task is running (user input functions check this flag before doing anything)
    3) start thread with task
    4) when done, change GUI back, reset flag

    I'd like to know if there's a better way before continuing.

  2. #2
    Super Moderator helloworld922's Avatar
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    Default Re: Update GUI before lengthy task

    A gui should not become un-responsive due to a long task running.

    If you're using a Swing layered design you can loop through all components which have been added to a particular component.

    JPanel somePanel = new JPanel();
    // .. add a bunch of stuff to that somePanel
    // disable everything on somePanel
    for(Component c : somePanel.getComponents())

    Similarly, you can automatically re-enable everything using the same technique.

    I would recommend running your task on a separate thread. To simplify your job, have the separate thread do the disabling/enabling of components.

    This solution has the benefit of allowing you to leave certain components active (say for example if you wanted a cancel button) and make your gui more user-friendly (no one likes a non-responsive window). It may very well be easier to design, too.

  3. #3
    Crazy Cat Lady KevinWorkman's Avatar
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    Default Re: Update GUI before lengthy task

    I agree with helloworld. But you might also look into using a GlassPane to restrict user input (informatively, not annoyingly).
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