Question

Im using Qt framework , and i looking for the best method to show the user im processing something
how in Qt i can:
put the main window in the background and pop up window to the foreground with
for example ” processing ” massage
until its done processing the ” processing ” window will close and the main window returns to the foreground .

Answer 1

Use QProgressDialog. It is designed for that kind of use. You can use the QProgressDialog as a modal dialog thus preventing any user interaction to your main window. QProgressDialog also gives you an easy way to present the progress of your processing and an optional pushbutton to abort processing.

Edit:

QProgressBar can be used in two states: progressing in steps or just showing busy state.

QProgressDialog’s progress bar cannot be used showing busy state because that would require setting QProgressDialog’s min and max values to 0, which immediately closes the progress dialog. However, you can give the QProgressDialog a new progress bar using setBar()-function. Then you can set this progress bar’s min, max and value to 0 and then getting the busy look.

QProgressDialog progressDialog("Processing...", "Abort", 0, INT_MAX, this);

QProgressBar* bar = new QProgressBar(&progressDialog);
bar->setRange(0, 0);
bar->setValue(0);
progress.setBar(bar);

progressDialog.setMinimumWidth(350);
progressDialog.setMinimumDuration(1000);
progressDialog.setWindowModality(Qt::WindowModal);
progressDialog.setValue(0);


// Do your time consuming processing here, but remember to change 
// the progress dialog's value a few times per second. 
// That will keep the busy indicator moving.
progressDialog.setValue(progressDialog.value() + 1);

// And check if the user has cancelled the processing
if (progressDialog.wasCanceled())
    break or return or whatever necessary


// When your processing is done, close the dialog.
progressDialog.close();