代码如下
MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    this->sence=new QGraphicsScene(0,0,this->width(),this->height());
    this->view=new QGraphicsView(this);
    this->view->setScene(this->sence);
//    this->view->setRenderHints(QPainter::TextAntialiasing | QPainter::Antialiasing);
//    this->setCentralWidget(this->view);
    QGraphicsEllipseItem* one=new QGraphicsEllipseItem();
    QGraphicsItem* two=new QGraphicsLineItem();
    QGraphicsEllipseItem* three=new QGraphicsEllipseItem();
    one->setBrush(QBrush(Qt::red));
    this->sence->addItem(one);
    this->sence->addItem(two);
    this->sence->addItem(three);
    this->sence->update();
    this->view->update();
    this->setCentralWidget(this->view);
}
有什么问题呢,窗口中央都是白的一片,什么都没有