文件目录

Teacher.h

#ifndef TEACHER_H
#define TEACHER_H

#include <QObject>

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

signals:
    void hungry(QString foodName);
    void hungry();


};

#endif // TEACHER_H

teacher.cpp

是信号，不需要实现

student.h

#ifndef STUDENT_H
#define STUDENT_H

#include <QObject>
#include <QString>

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

signals:

public slots:
    // void 返回值类型，需要声明和实现
    // 可以有参数，可以发生重载
    void say();
    void say(QString foodName);

};

#endif // STUDENT_H

student.cpp

#include "student.h"
#include <QDebug>


Student::Student(QObject *parent) : QObject(parent)
{

}

void Student::say()
{
    qDebug() << "Go Away!";

}

void Student::say(QString foodName)
{
    // QString先转QByteArray，然后转Char *
    qDebug() << "eat " << foodName.toUtf8().data();
}

mainwindows.cpp

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



MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    this->setFixedSize(200, 100);

    QPushButton * buttonTech = new QPushButton;
    buttonTech->resize(80, 40);
    buttonTech->setText("class over");
    buttonTech->move(100, 10);
    buttonTech->setParent(this);

    this->tea = new Teacher(this);      // C++创建对象方式，h文件声明，C文件指针new
    this->stu = new Student(this);

    // 函数重载，无参，不知道调用哪个地址的同名函数
    //connect(tea, &Teacher::hungry, stu, &Student::say);
    // 函数重载，有参,定义函数指针，指向类内函数的地址
    void(Teacher:: *teaSingal)(QString) = &Teacher::hungry;
    void(Student:: *stuSlot)(QString) = &Student::say;
    connect(tea, teaSingal, stu, stuSlot);    // 老师hungry信号和学生say槽函数连接
    classIsOver();      // 发射老师hungry信号

    // 按钮触发槽函数, 第三个参数，信号的接受者是当前窗口类，并触发窗口的槽函数
    // 按钮触发的信号和这个窗口的classIsOver函数相连接，这个函数发送emit hungry信号
    connect(buttonTech, &QPushButton::clicked, this, &MainWindow::classIsOver);

    // 无参数的信号和槽连接
    void(Teacher:: *teaSingalN)(void) = &Teacher::hungry;
    void(Student:: *stuSlotN)(void) = &Student::say;
    connect(tea, teaSingalN, stu, stuSlotN);
    classIsOver();      // 发射老师hungry信号

    // 信号和信号的连接
    QPushButton * button = new QPushButton("signal", this);
    button->resize(50, 50);
    button->move(0, 0);
    connect(button, &QPushButton::clicked, stu, stuSlotN);

    // 信号断开, 上一行代码的connect，无效了
    disconnect(button, &QPushButton::clicked, stu, stuSlotN);
}

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

void MainWindow::classIsOver()
{
    emit tea->hungry("asd");
    emit tea->hungry();
}

标签：QT,void,hungry,用法,细节,Student,include,MainWindow,Teacher
来源： https://www.cnblogs.com/starc/p/16081356.html