按钮显示不了，很简单的程序，大家帮帮忙呀 [复制链接]

大家帮忙看一下吧，我的两个按钮怎么显示不出来啊？很简单的一段代码。
#include <QImage>
#include <QWidget>

class QToolButton;

class display : public QWidget
{

public:
    display(QWidget *parent = 0);

protected:
    void paintEvent(QPaintEvent *event);

private:

    QToolButton *zoomInButton;
    QToolButton *zoomOutButton;
    QImage image;
    
};

#include "display.h"

#include <QtGui>
#include <QPainter>

display::display(QWidget *parent)
: QWidget(parent)
{
    setBackgroundRole(QPalette::Dark);
    setAutoFillBackground(true);
    setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);
    setFocusPolicy(Qt::StrongFocus);

    zoomInButton = new QToolButton(this);
    zoomInButton->setIcon(QIcon(":/images/zoomin.png"));
    zoomInButton->adjustSize();
    zoomInButton->move(5,5);

    zoomOutButton = new QToolButton(this);
    zoomOutButton->setIcon(QIcon(":/images/zoomout.png"));
    zoomOutButton->adjustSize();
    zoomOutButton->move(40,5);
    
}

void display::paintEvent(QPaintEvent * /* event */)
{
    image = QImage(size(),QImage::Format_RGB16);
    image.fill(0xffff);
    QPainter imagePainter(&image);
    imagePainter.initFrom(this);
    imagePainter.setPen(QColor(255,0,0));
    imagePainter.setRenderHint(QPainter::Antialiasing,true);
    imagePainter.drawEllipse(20,20,40,80);
    imagePainter.end();
    QPainter widgetPainter(this);
    widgetPainter.drawImage(0,0,image);
}

有哪位看出来问题出在哪里了吗？指点一下啊。

你的main.cpp是怎样写的。

没有show，也没有layout，你要怎么显示？