Qt中重绘制窗口方法：

void CircleWidget::paintEvent(QPaintEvent * event)
{
    QPainter painter(this);

    int wight = this->width();
    int heigth = this->height();

    if (m_timers==0)
    {
    
        QColor green(0, 0, 0xff);
        QPen pen(green);

        painter.setBrush(QBrush(QColor(0x00, 0xFF, 0x00)));
        pen.setStyle(Qt::DashLine);
        painter.setPen(pen);
        m_timers++;
    }
    else
    {
        

        QColor red(0xff,0 ,0);
        QPen pen(red);

        painter.setBrush(QBrush(QColor(0xFF,0x00,0x00)));
        pen.setStyle(Qt::DashLine);
        painter.setPen(pen);    
        m_timers = 0;
    }
    painter.drawRect(0, 0, 100, 100);
}

void CircleWidget::timerEvent(QTimerEvent* event)
{
    if (event->timerId() == m_TimerID)
    {
        update();
    }
}