QPalette help pls

[munna]

Hi,

I have a widget whose constructor is something like this :

QPalette pal;
	pal.setBrush(QPalette::Window,QBrush(QPixmap(":/images/background.png")));
	setPalette(pal);
 
	nameLabel = new QLabel(tr("Name"),this);
	nameLabel->setFont(QFont("Arial",9));
 
	QIcon icon(":/images/plusbutton.png");
	addButton = new QPushButton(tr(""),this);
	addButton->setIcon(icon);
	addButton->setFlat(true);
	addButton->setFixedSize(20,20);
	connect(addButton,SIGNAL(pressed()),this,SLOT(addContact()));
 
	QHBoxLayout *hLay = new QHBoxLayout;
	hLay->addSpacing(5);
	hLay->addWidget(nameLabel);
	hLay->addStretch(1);
	hLay->addWidget(addButton);
 
	nameListWidget = new NameListWidget(c,this);
	connect(nameListWidget,SIGNAL(currentItemChanged(QListWidgetItem *,QListWidgetItem *)),
		this,SLOT(selectionChanged(QListWidgetItem *,QListWidgetItem *)));
	connect(nameListWidget,SIGNAL(clearContact()),this,SLOT(clearContact()));
 
	//connect(nameListWidget,SIGNAL(currentRowChanged(int )),this,SLOT(selectionChanged(int )));
 
	QVBoxLayout *mainLayout = new QVBoxLayout;
	mainLayout->setMargin(0);
	mainLayout->addSpacing(5);
	mainLayout->addLayout(hLay);
	mainLayout->addWidget(nameListWidget);
	setLayout(mainLayout);

QPalette pal;
	pal.setBrush(QPalette::Window,QBrush(QPixmap(":/images/background.png")));
	setPalette(pal);

	nameLabel = new QLabel(tr("Name"),this);
	nameLabel->setFont(QFont("Arial",9));

	QIcon icon(":/images/plusbutton.png");
	addButton = new QPushButton(tr(""),this);
	addButton->setIcon(icon);
	addButton->setFlat(true);
	addButton->setFixedSize(20,20);
	connect(addButton,SIGNAL(pressed()),this,SLOT(addContact()));

	QHBoxLayout *hLay = new QHBoxLayout;
	hLay->addSpacing(5);
	hLay->addWidget(nameLabel);
	hLay->addStretch(1);
	hLay->addWidget(addButton);

	nameListWidget = new NameListWidget(c,this);
	connect(nameListWidget,SIGNAL(currentItemChanged(QListWidgetItem *,QListWidgetItem *)),
		this,SLOT(selectionChanged(QListWidgetItem *,QListWidgetItem *)));
	connect(nameListWidget,SIGNAL(clearContact()),this,SLOT(clearContact()));

	//connect(nameListWidget,SIGNAL(currentRowChanged(int )),this,SLOT(selectionChanged(int )));

	QVBoxLayout *mainLayout = new QVBoxLayout;
	mainLayout->setMargin(0);
	mainLayout->addSpacing(5);
	mainLayout->addLayout(hLay);
	mainLayout->addWidget(nameListWidget);
	setLayout(mainLayout);

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The background is not changing though I have set the palette.

Can someone please help ?
Thanks a lot.