widget.h：

#ifndef WIDGET_H
#define WIDGET_H

#include

class Widget : public QWidget
{
Q_OBJECT

public:
Widget(QWidget *parent = 0);
~Widget();
public slots:
void showColor();
};

#endif // WIDGET_H

widget.cpp:

#include "widget.h"
#include
#include
#include
#include //调色板
#include
#include
Widget::Widget(QWidget *parent)
: QWidget(parent)
{
this->resize(600,480);
QPalette qpalette=this->palette();
QHBoxLayout *s=new QHBoxLayout(this);
qpalette.color( QPalette::WindowText);
qpalette.setColor(QPalette::WindowText,QColor(255,0,0));
qpalette.setColor(QPalette::Background,QColor("#0f8Fb0"));
this->setPalette(qpalette);
QPushButton *qp=new QPushButton("打开",this);
QLabel* ql=new QLabel("打开",this);
s->addWidget(qp);
s->addWidget(ql);
connect(qp,SIGNAL(clicked()),this,SLOT(showColor()));
}
void Widget::showColor()
{
QColor qc=QColorDialog::getColor(QColor("#0023ff"),this,"dfsd");
if(qc.isValid())
{
QPalette temp=this->palette();
temp.setColor(QPalette::Background,qc);
this->setPalette(temp);
}
}
Widget::~Widget()
{

}

main.cpp:

#include "widget.h"
#include

int main(int argc, char *argv[])
{
QApplication a(argc, argv);
Widget w;
w.show();

return a.exec();  

}

效果图: