qt信号和槽

按钮->点击->窗口->关闭窗口

connect(信号的发送者，发送具体信号，信号的接收者，信号的处理);

信号处理函数称为槽

信号槽的优点，松散耦合，信号发送端和接收端本身是没有关联的，通过connect连接将两端耦合在一起

//点击按钮，关闭当前窗口
connect(myBtn, &QPushButton::clicked, this, &QWidget::close);

自定义信号和槽

teacher.h

#ifndef TEACHER_H
#define TEACHER_H

#include <QObject>

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

    //自定义信号写到signals下
    //返回值类型为void，只需要声明，不需要实现
    //可以有参数，可以重载
signals:
    void hungry();

};

#endif // TEACHER_H

student.h

#ifndef STUDENT_H
#define STUDENT_H

#include <QObject>

class Student : public QObject
{
    Q_OBJECT
public:
    explicit Student(QObject *parent = nullptr);
    //可以写到public下
    //返回值类型为void，需要声明，也需要实现
    //可以有参数，也可以重载
    void please();

signals:

};

#endif // STUDENT_H

student.cpp

#include "student.h"
#include <iostream>
Student::Student(QObject *parent) : QObject(parent)
{

}
void Student::please()
{
    std::cout << "please teacher eat dinner" << std::endl;
}

mywidget.h

#ifndef MYWIDGET_H
#define MYWIDGET_H

#include <QWidget>
#include "teacher.h"
#include "student.h"
class myWidget : public QWidget
{
    Q_OBJECT

public:
    myWidget(QWidget *parent = nullptr);

    Teacher *t = new Teacher(this);
    Student *s = new Student(this);


    ~myWidget();
};
#endif // MYWIDGET_H

mywidegt.cpp

#include "mywidget.h"

myWidget::myWidget(QWidget *parent)
    : QWidget(parent)
{
    connect(this->t, &Teacher::hungry, this->s, &Student::please); //建立信号与槽的连接
    emit(this->t->hungry()); //发射信号

}

myWidget::~myWidget()
{
}