QT控件添加信号

#ifndef MYLINEEDIT_H
#define MYLINEEDIT_H

#include <QLineEdit>
#include <QMouseEvent>

class MyLineEdit : public QLineEdit
{
    Q_OBJECT
public:
    explicit MyLineEdit(QWidget *parent = 0);
    
protected:
    virtual void mousePressEvent(QMouseEvent *event);   //QWidget中到保护成员函数

signals:
    void LineEditClicked();
    
public slots:
    
};

#endif // MYLINEEDIT_H

#include "mylineedit.h"

MyLineEdit::MyLineEdit(QWidget *parent) :
    QLineEdit(parent)
{
}

void MyLineEdit::mousePressEvent(QMouseEvent *event)
{
    if (event->button() == Qt::LeftButton)
    {
       emit LineEditClicked();
    }
    QLineEdit::mousePressEvent(event);
}