clickedLabel.h

#ifndef CLICKLABEL_H

#define CLICKLABEL_H

#include <QLabel>

#include <QMouseEvent>

class ClickLabel : public QLabel

{

    Q_OBJECT

public:

    explicit ClickLabel(QWidget *parent = 0);

    ~ClickLabel();

signals:

    void clicked();//自定义clicked()信号,在mousePressEvent事件发生时触发

protected:

    virtual void mousePressEvent(QMouseEvent* event);//重写mousePressEvent事件

};

#endif // CLICKLABEL_H

clickedLabel.cpp

#include "clicklabel.h"

ClickLabel::ClickLabel(QWidget* parent)

    : QLabel(parent)

{

}

ClickLabel::~ClickLabel()

{

}

void ClickLabel::mousePressEvent(QMouseEvent *event)//重写mousePressEvent事件,检测事件类型是不是点击了鼠标左键

{

    //如果单击了就触发clicked信号

    if (event->button() == Qt::LeftButton) {

        //触发clicked信号

        emit clicked();

    }

    //将该事件传给父类处理

    QLabel::mousePressEvent(event);

}

使用前把qlabel的类提升为ClickLabel 
 

添加SLOT函数

private slots:

    void clicklabel_clicked();  //定义槽函数处理label clicked

connect

 connect(ui->setrefresh_img_label, SIGNAL(clicked()), this, SLOT(clicklabel_clicked()));