Question

can I force my Qt application to use different look and feel just like it is done in KDE ?

Answer 1

You can always change styles of widgets using QApplication::setStyle.
There are a few predefined options available in Qt4.

In main.cpp do something like this

#include <QPlastiqueStyle>

int main(int argc, char *argv[])
{
[...]

    QApplication::setStyle(new QPlastiqueStyle());
}

This way your application will alwyas look the same on different OS.
In my opinion Plastique looks better under windowsXP/2000 then default QWindowsXPStyle.
Cleanlooks is quite nice too.

There are other options:

#include <QPlastiqueStyle>
#include <QCleanlooksStyle>
#include <QWindowsXPStyle>
#include <QWindowsVistaStyle>
#include <QMotifStyle>
#include <QCDEStyle>

I hope this helps.