Show progress of a time consuming operation

[rainman110]

Hi,

i am writing a program which calculates the irradiation dose for cancer treatment. This can take some time, so my idea was, to show up a simple dialog with a progress-bar in it. I dont know really how to do it because when the dialog is started, the program stops as long it is opened.

I like to implement such an interface:

class ProgressDialog : public QWidget {
public:
   signalProgress(); //the bar should move a bit to right
   setTotalProgress(int); //maxValue of progress bar
}

class ProgressDialog : public QWidget {
public:
   signalProgress(); //the bar should move a bit to right
   setTotalProgress(int); //maxValue of progress bar
}

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My programm is a console program actually. I dont want to do all the calulation stuff in a window. So - how should i implement the main() function. My idea was like following, but this won't work:

void doComplicatedStuff(ProgressDialog& pd){
   while(calculating){
      someCalculation;
      pd.signalProgress();
   }
}
 
main(argc,argv){
    QApplication a(argc,argv);
    ProgressDialog pd;
    pd.show();
    doComplicatedStuff(pd);//no dialog visible
    return a.exec(); //here, the dialog pops up - swapping last lines is no solution
}

void doComplicatedStuff(ProgressDialog& pd){
   while(calculating){
      someCalculation;
      pd.signalProgress();
   }
}

main(argc,argv){
    QApplication a(argc,argv);
    ProgressDialog pd;
    pd.show();
    doComplicatedStuff(pd);//no dialog visible
    return a.exec(); //here, the dialog pops up - swapping last lines is no solution
}

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So what can i do instead? I hope, you can help me.
Thanks! Thanks! Thanks!

Cheers

[jpn]

Hi, you might want to take a look at QProgressDialog.

[wysota]

And QCoreApplication::processEvents.

[rainman110]

Thanks for your reply! I have found QProgressDialog already but it doesnt solve my problem, that the application is unresponsible.
What can I do with QCoreApplication::processEvents? I am really a newbie in qt programming.
I tried to do it with seperate threads - the main thread for the dialog, an extra thread for the calculation - but there the problem is, that you can't connect signal and slots from different threads (runtime exception).

[wysota]

With processEvents() you can.... process pending events thus making your application responsive.

[rainman110]

I think I have to do more reading about this stuff. Thank you!

[rainman110]

Okay... i read a bit about it. How should be now the semantic of the main function

like this?:

int main(argc,argv){
   QApplication app(argc,argv);
   QProgressDialog pd();
   pd.setrange(0,100);
 
   //now the calculation loop?
   for(int i = 0; i < 100, ++i){
      someCalculation;
      pd.setValue(i);
      app.processEvents();
   }
   return app.exec();
}

int main(argc,argv){
   QApplication app(argc,argv);
   QProgressDialog pd();
   pd.setrange(0,100);

   //now the calculation loop?
   for(int i = 0; i < 100, ++i){
      someCalculation;
      pd.setValue(i);
      app.processEvents();
   }
   return app.exec();
}

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Is this right? I dont know really, where to place the app.exec - why i need it.
Is this the right order, or should the app.exec() be placed over the calculation loop?

[jpn]

You don't have to enter to the event loop of the application at all if showing a progress bar is all what your application does...