qt installEventFilter的使用

#include "widget.h"
#include "ui_widget.h"
#include 

Widget::Widget(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::Widget)
{
    ui->setupUi(this);

    ui->label->installEventFilter(this);
    ui->label->setObjectName("hello");
}

Widget::~Widget()
{
    delete ui;
}


bool Widget::eventFilter(QObject *obj, QEvent *event)
{
    //当鼠标按下label时，输出该对象名hello
    if (event->type() == QEvent::MouseButtonPress)
    {
        if (obj->inherits("QLabel"))
        {
            QLabel* label = qobject_cast(obj);
            if(label)
                qDebug() << label->objectName();
        }
    }

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