busy progress bar without thread ?

[npc]

Hi,

I am using progress bar which showing a busy mode ( minimum = maximum = 0 ).
and my code goes like this..

progressBar.setMinimum(0);
progressBar.setMaximum(0);
fn();
progressBar.hide();

progressBar.setMinimum(0);
progressBar.setMaximum(0);
fn();
progressBar.hide();

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When the process running in fn() the progress bar is not showing the busy mode.

But I want to show the progressbar in a busy mode till the fn retuns.
should I use threads for this ? or is there any easy way ?

Thanks
*npc*

[high_flyer]

you should call the progress bar in your fn() function.
Show your fn() fucntion code.

[npc]

It is a big code which is used to collect the system informations.

I called the progress bar in fn() like this

fn()
{
 
fn1();
prgressBar.show();
fn2();
progressBar.show();
 
}

fn()
{

fn1();
prgressBar.show();
fn2();
progressBar.show();

}

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But it doesnt helps me

Thanks,
*npc*

[high_flyer]

but where do you call setValue()?

[npc]

Because I want to show busy indicator in progress bar, I set minimum and maximum values as 0.

So what is the need of calling setvalue ? ..if it necessary what value have to send ?

Thanks,
*npc*

[high_flyer]

Well lets see -
How can the progress bar know, when to progress the bar?
I suggest you read the docs first:
http://doc.trolltech.com/4.2/qprogressbar.html

[wysota]

I think you're missing some QCoreApplication::processEvents() calls...

[high_flyer]

Wysota - I think so too, but even that wont help if he doesen't call setValue()...

[npc]

I think you're missing some QCoreApplication:rocessEvents() calls...

Exactly.. Thanks Wysota.

Now its working fine for me.. I called QCoreApplication:rocessEvents() in sub functions.

But I never called setValue() anywhere

[high_flyer]

So how is the progress bar incremented?

The progress bar uses the concept of steps. You set it up by specifying the minimum and maximum possible step values, and it will display the percentage of steps that have been completed when you later give it the current step value. The percentage is calculated by dividing the progress (value() - minimum()) divided by maximum() - minimum().

[wysota]

It's not, it's just spinning all the time like in Star Trek or Knightrider. This is a special case of using a progress bar that is activated by setting the range of values to [0,0].

[high_flyer]

Oh I see - it didn't sink in that he used [0,0].
Sorry about that.

[bmn]

how to make QProgress bar busy works

my code

ui.initStatus->setRange(0,0);
qApp->processEvents ( );

ui.initStatus->setRange(0,0);
qApp->processEvents ( );

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but, nothing happens.

thanks!

[jpn]

Calling processEvents() once before a busy loop won't do the trick. You have to call it every now and then during the busy loop. You must let the application to process its events meanwhile you do the calculation. Otherwise the application won't be able to update any widget.

[bmn]

for( int i=0; i<1000; i++ ){
	ui.initStatus->setMaximum(0);
	ui.initStatus->setMinimum(0);
	qApp->processEvents();
}

for( int i=0; i<1000; i++ ){
	ui.initStatus->setMaximum(0);
	ui.initStatus->setMinimum(0);
	qApp->processEvents();
}

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Don't work

ui.initStatus->setMaximum(0);
ui.initStatus->setMinimum(0);
for( int i=0; i<1000; i++ )
	qApp->processEvents();

ui.initStatus->setMaximum(0);
ui.initStatus->setMinimum(0);
for( int i=0; i<1000; i++ )
	qApp->processEvents();

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Don't work

[jpn]

What does "Don't work" mean? Is the progress bar visible at all? Is the user interface responsible? The latter version is the more correct one, there is no need to set the range many times.

[bmn]

ui.initStatus->setMaximum(0);
ui.initStatus->setMinimum(0);
this->timer = new QTimer(this);
connect(this->timer, SIGNAL(timeout()), this, SLOT(advanceProgressBar()));
this->timer->start(100);
 
void advanceProgressBar(){
    qApp->processEvents();
}

ui.initStatus->setMaximum(0);
ui.initStatus->setMinimum(0);
this->timer = new QTimer(this);
connect(this->timer, SIGNAL(timeout()), this, SLOT(advanceProgressBar()));
this->timer->start(100);

void advanceProgressBar(){
    qApp->processEvents();
}

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Don't work

how...
thanks!!

[bmn]

the bar does not move!
don't increment...it is stopped

[jpn]

Works for me:

// main.cpp
#include <QtGui>
 
int main(int argc, char* argv[])
{
    QApplication app(argc, argv);
    QProgressBar progressBar;
    progressBar.setMinimum(0);
    progressBar.setMaximum(0);
    progressBar.show();
    return app.exec();
}

// main.cpp
#include <QtGui>

int main(int argc, char* argv[])
{
    QApplication app(argc, argv);
    QProgressBar progressBar;
    progressBar.setMinimum(0);
    progressBar.setMaximum(0);
    progressBar.show();
    return app.exec();
}

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[bmn]

Works for me:

// main.cpp
#include <QtGui>
 
int main(int argc, char* argv[])
{
    QApplication app(argc, argv);
    QProgressBar progressBar;
    progressBar.setMinimum(0);
    progressBar.setMaximum(0);
    progressBar.show();
    return app.exec();
}

// main.cpp
#include <QtGui>

int main(int argc, char* argv[])
{
    QApplication app(argc, argv);
    QProgressBar progressBar;
    progressBar.setMinimum(0);
    progressBar.setMaximum(0);
    progressBar.show();
    return app.exec();
}

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Don't work... see

QApplication app(argc, argv);
QMainWindow window;
QProgressBar* progressBar = new QProgressBar(&window);
progressBar->setMaximumHeight(16);
progressBar->setMaximumWidth(200);
progressBar->setTextVisible(false);
progressBar->setMaximum(0);
progressBar->setMinimum(0);
 
progressBar->show(); // ??? don't move the bar
 
window.statusBar()->addPermanentWidget(progressBar);
window.statusBar()->showMessage("Loading");
window.show();
app.exec();

QApplication app(argc, argv);
QMainWindow window;
QProgressBar* progressBar = new QProgressBar(&window);
progressBar->setMaximumHeight(16);
progressBar->setMaximumWidth(200);
progressBar->setTextVisible(false);
progressBar->setMaximum(0);
progressBar->setMinimum(0);

progressBar->show(); // ??? don't move the bar

window.statusBar()->addPermanentWidget(progressBar);
window.statusBar()->showMessage("Loading");
window.show();
app.exec();

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