[Qt-interest] QProgressBar kind of functionality withQProgressDialog (Size of file being copied not known)

[Ben Swerts]

HI Usman,

I hope you understood from the other posts that you need to let the
eventloop spin (e.g. QApplication::processEvents) such that the
QProgressDialog can be shown. There are, however, a few other caveats you
should be aware of:

- QProgressDialog is only shown after the specified minimumDuration(). The
default value is 4 seconds, but as you mentioned that the process runs for a
few minutes you don't have to worry about that.

- The progress bar can be made moving by setting the same minimum and
maximum value. I had to perform a workaround (Qt 4.3.3) to actually get it
to move in the QProgressDialog:

  progressDialog->setRange(0, 1);
  progressDialog->setValue(0);
  progressDialog->setRange(0, 0);

I don't know whether this fix is still needed with the latest version of Qt.

Hope it helps.
Greets,


	Ben

> Let me rephrase my question:
> 
> Can i show the progress of my operation with the help of a blue fluid
> moving to and from in the bar of QProgressDialog?
> 
> I want such functionality because i don't know the size of the operation.
> 
> I went through QProgressDialog class reference but invain. Kindly suggest
> something.
> 
> Thanks
> 
> 
> On Mon, May 25, 2009 at 12:33 PM, Usman Ajmal <uzmanajmal at gmail.com>
> wrote:
> 
> 
> 	Hi,
> 	I set setMaximum() and setMinimum(), of QProgressBar, equal to zero
> which gave be the ability to show a kinda progress without showing the
> percentage of the operation completed. It only showed a blue fluid moving
> to and from in the bar which showed that something is being copied.
> 
> 	Now i want to have the same kind of progress presentation with
> QProgressDialog but i could not see anything showing up when i start the
> operation. I don't see even the dialog.
> 
> 	Following z the snippet from my code: In following code 'line' is
> QString and 'image' is QTextStream.
> 
> 	QProgressDialog progress("Copying files...", "Abort Copy", 0, 0,
> this);
> 	while (!line.isNull())
> 	            {
> 	                if (progress.wasCanceled())
> 	                     break;
> 	                line = in.readLine();
> 	                image<<line<<endl;
> 
> 	            }
> 
> 	What else do i need to add here?
> 
> 	Thanks.
> 
> 	--
> 	Usman
> 
>