connect函数

connect(sender, signal, receiver, slot);

槽函数示例

void student:: treat(QString foodname)
void student:: treat(int index)

由上可见，有两个名字相同，但形参不同的槽函数。

可以通过函数指针的方式，用指针指向具体的函数。如下所示

    //连接
    //connect(zt,&teacher::hungery,st,&student::treat);
    void (teacher:: *teachersignals)(QString) = &teacher::hungery;
    void (student:: *studentslots)(QString) = &student::treat;
    connect(zt,teachersignals,st,studentslots);

示例

void student::treat(QString foodname)
{
    qDebug()<<"请老师吃"<<foodname;
}

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

signals:
    //自定义信号
    //返回值是void，只需要声明，不需要实现
    //可以有参数，可以重载
    void hungery();
    void hungery(QString foodname);
};

#include "mainwindow.h"
#include "ui_mainwindow.h"

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

    //创建对象
    this->zt = new teacher(this);
    this->st = new student(this);

    //连接
    //connect(zt,&teacher::hungery,st,&student::treat);
    void (teacher:: *teachersignals)(QString) = &teacher::hungery;
    void (student:: *studentslots)(QString) = &student::treat;
    connect(zt,teachersignals,st,studentslots);
    
    classover();

}
void MainWindow::classover()
{
    //emit 触发信号
   // emit zt->hungery();
    emit zt->hungery("宫保鸡丁");
}

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