重载自定义信号与槽

重载信号与槽

1. 添加信号声明

class Sender : public QObject
{
    Q_OBJECT
public:
    explicit Sender(QObject *parent = nullptr);

signals:
    void sendSignal();
    void sendSignal(QString message);
};

2. 添加槽声明

class Sendee : public QObject
{
    Q_OBJECT
public:
    explicit Sendee(QObject *parent = nullptr);

signals:

public slots:
    void receiveSignal();
    void receiveSignal(QString message);
};

3. 实现重载槽函数 

void Sendee::receiveSignal(QString message) {
    qDebug()<<"We have received the signal.The message is"<<message;
}

添加函数指针

因为重载了信号函数与槽函数，原先的连接函数存在歧义；故而需要添加函数指针指明待连接的信号函数与槽函数，以消除歧义

#include <QPushButton>
#include "sendee.h"

Widget::Widget(QWidget *parent)
    : QWidget(parent)
{
    QPushButton *btn = new QPushButton("发送", this);
    connect(btn, &QPushButton::clicked, this, &Widget::emitSignal);

    sder = new Sender();
    Sendee* sdee = new Sendee();

    void (Sender::*send)(QString) = &Sender::sendSignal;
    void (Sendee::*receive)(QString) = &Sendee::receiveSignal;
    connect(sder, send, sdee, receive);
}

void Widget::emitSignal() {
    emit sder->sendSignal("Hello, world of QT!");
}

 简便版：

#include <QPushButton>
#include "sendee.h"

Widget::Widget(QWidget *parent)
    : QWidget(parent)
{
    QPushButton *btn = new QPushButton("发送", this);
    connect(btn, &QPushButton::clicked, this, &Widget::emitSignal);

    sder = new Sender();
    Sendee* sdee = new Sendee();

    connect(
        sder,
        qOverload<QString>(&Sender::sendSignal),
        sdee,
        qOverload<QString>(&Sendee::receiveSignal)
    );
}

void Widget::emitSignal() {
    emit sder->sendSignal("Hello, world of QT!");
}

实现效果