9_1.cpp

一个qt设计的教程

#include <qapplication.h>
#include <qwidget.h>
#include <qpainter.h>

class MyMainWindow:public QWidget
{
 public:
    MyMainWindow();
 private:
    void paintEvent(QPaintEvent*);
    QPainter *paint;
};

void MyMainWindow::paintEvent(QPaintEvent*)
{
 paint = new QPainter;
 paint->begin(this);
 paint->drawRect(20,20,160,160);
 paint->end();
}

MyMainWindow::MyMainWindow()
{
 setGeometry(100,100,200,200);
}

main(int argc,char **argv)
{
 QApplication a(argc,argv);
 MyMainWindow w;

 a.setMainWidget(&w);
 w.show();
 a.exec();
}