Question

I have a for-loop which is setting the value of the progress bar on every iteration.
The for-loop executes the setProgress-method described here:

void setProgress(int progStep){
    progressBar->setValue(progStep);
    progStep++;
    QTextStream(stdout) << progStep << " " << progSum << endl;
}

I can print out that last line, so the method is executed but the GUI of the progress bar is not updated every time.

When I have a maximum value of 25 (and min 0), the method prints every number from 0-25. My goal is to have the progress bar to then show 25 different percentage values during this execution.

Structure:

 for(.....) {
     .....
     .....
     setProgress(progStep);
 }

What actually happens is that it updates the progress bar with percentage values about 2-3 times. The for-loop takes about 30 seconds so it should definitely be able to make 25 percentage updates.

How can I solve this?

Answer 1

You have to call QApplication::processEvents() after calling setProgress(progStep), to let the GUI thread update the progress bar.