自定义的QWidget [复制链接]

为什么我自己定义的QWidget，我重写了paintEvent方法，
如果我就在FORM上放这个WIDGET是没有问题，但如果把它再包含一层的话就不显示了
请问这是为什么呢,下面是该WIDGET的代码

.h文件
#include <QtGui>

class ClockWidget: public QLabel {
    Q_OBJECT
public:
    ClockWidget(QWidget *parent = 0);
    ClockWidget();
    ~ClockWidget();
protected:
    void paintEvent(QPaintEvent *e);
};

.cpp文件


#include "clockwidget.h"

ClockWidget::ClockWidget(QWidget *parent):QLabel(parent)
{
    this->setAutoFillBackground(true);
    QTimer *timer = new QTimer(this);
    //连接信号与槽
    connect(timer, SIGNAL(timeout()), this, SLOT(update()));
    timer->start(1000);
}

ClockWidget::~ClockWidget()
{

    return ;
}

void ClockWidget::paintEvent(QPaintEvent *e)
{
    //下面三个数组用来定义表针的三个顶点，以便后面的填充
    static const QPoint hourHand[3] = {
         QPoint(1, 2),
     QPoint(-1, 2),
     QPoint(0, -4)
};
     static const QPoint minuteHand[3] = {
         QPoint(1, 2),
     QPoint(-1, 2),
     QPoint(0, -7)
};
     static const QPoint secondHand[3] = {
         QPoint(1, 3),
     QPoint(-1, 3),
     QPoint(0, -10)
};
     //填充表针的颜色
     QColor hourColor(127, 0, 127);
     QColor minuteColor(0, 127, 127, 191);
     QColor secondColor(127, 127,0,120);
     //绘制的范围
             int side = qMin(width(), height());
     //获取当前的时间
             QTime time = QTime::currentTime();
     //声明用来绘图用的“画家”
             QPainter painter(this);
     painter.setRenderHint(QPainter::Antialiasing);
     //重新定位坐标起始点点
             painter.translate(60, 60);
     //设定花布的边界
             painter.scale(side / 200.0, side / 200.0);
     //填充时针，不需要边线所以NoPen
             painter.setPen(Qt::NoPen);
     //画刷颜色设定
             painter.setBrush(hourColor);
     //保存“画家”的状态
             painter.save();
     //将“画家”（的”视角“）根据时间参数转移
             painter.rotate(30.0 * ((time.hour() + time.minute() / 60.0)));
     //填充时针的区域
             painter.drawConvexPolygon(hourHand, 3);
     //恢复填充前“画家”的状态
             painter.restore();
     //下面画表示小时的刻度，此时要用到画笔（因为要划线）
     painter.setPen(hourColor);
     //后面的跟前面的类似，分别绘制了分针和秒针，及相应的刻度，我就不废话了
     painter.setPen(Qt::NoPen);
     painter.setBrush(minuteColor);
     painter.save();
     painter.rotate(6.0 * (time.minute() + time.second() / 60.0));
     painter.drawConvexPolygon(minuteHand, 3);
     painter.restore();

             painter.setPen(minuteColor);


    painter.setPen(Qt::NoPen);
    painter.setBrush(secondColor);

    painter.save();
    painter.rotate(6.0*time.second());
    painter.drawConvexPolygon(secondHand,3);
    painter.restore();

}