Login - what is the right way?

I've got my main application written and working. Now I need to add a 'login 
screen' that opens when they start the application. If they login correctly, 
then my  application's main window should be shown.

I got it working by building a login screen, then in the OK button click event  
I validate the login, and if it is good, then (still in the button click 
event) I do
   # Now start the real app.
    my $a = Qt::Application(\@ARGV);
    my $w = MMInternal::QTClient::UI;
    $a->setMainWidget($w);
    $w->show;
    exit $a->exec;

This works - but is seems weird to me to have the main application started 
from inside the OK button click.  Is this the best way - or is there a better 
way to do it?

Thanks,

-- 
Joe Claborn
[email protected]
254-829-2448