c++ - Forcing the Qt GUI to update before entering a separate function

Question

This seems like it should be automatic, but apparently it's not. I have the following code:

    ui.my_label->setText("Test 1...");
    ui.my_label->adjustSize();

    processThatTakesAbout30SecondsToFinish(files[0].toStdString());

    ui.my_label->setText("Finished.");
    ui.my_label->adjustSize();

What is happening is that I never see "Test1...", as the GUI seems to hang until the following function completes, and I eventaully only see "Finished.".

How can I make sure the GUI is updating before it enters that function?
Thanks.

Answer 1

You shuld be able to process the event queue before entering your code if you;

#include <QApplication>

and, when you want to refresh your GUI, call;

qApp->processEvents();

Note that it may be a good idea to let your long running process call that function now and then, to make your GUI feel more responsive.