I tried the codes in FC6 :
code:
.......
#include "../imagesource/app_hover.xpm"
........

QPixmap app_Normal;
app_Normal.convertFromImage(app_normal);
QFile debugFile("/root/debughuiqin.txt");
if( debugFile.open(IO_Append | IO_WriteOnly) )
{
QTextStream debugOut( &debugFile );
if(app_Normal.isNull())
debugOut<<"this is a null pixmap"<<endl;
else debugOut<<"this is not a null pixmap"<<endl;
debugFile.close();
}


menuwgt=new QFrame(this) ;
menu1=new QMenuBar(menuwgt) ;
menu1->setPaletteBackgroundPixmap(app_Normal);
the result is "this is not a null pixmap"


thank you for your reply