Qt事件

    ui->label->installEventFilter(this);   //label控件安装过滤器
    ui->label->setMouseTracking(true);  //设置鼠标跟踪


bool Widget::eventFilter(QObject *watched, QEvent *event)
{
    if(watched == ui->label)
    {
        static int t = 0;
        QMouseEvent *env = (QMouseEvent *)(event);  //鼠标事件
        if(event->type() == QEvent::MouseMove)   //移动事件
        {
            ui->label->setText(QString("%1").arg(t++));
            return true;
        }

    }
        return QWidget::eventFilter(watched,event);
}