student.h :

#ifndef STUDENT_H
#define STUDENT_H

#include <QObject>

class Student : public QObject
{
    Q_OBJECT
public:
    explicit Student(QObject *parent = 0);

signals:

public slots:
    //自定義信號  寫到slots下，低版本可以卸載public下
    //返回值是void  需要聲明  也需要實現(xiàn)
    //可以有參數(shù)悯仙，可以重載
    void treat();
    void treat(QString FoodName);
};

#endif // STUDENT_H

student.cpp :

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


Student::Student(QObject *parent) :
    QObject(parent)
{
}
void Student::treat()
{
    qDebug()<<"請老師吃飯";


}
void Student::treat(QString FoodName)
{
    qDebug()<<"請老師吃:"<<FoodName.toUtf8().data();


}

teacher.h :

#ifndef TEACHER_H
#define TEACHER_H

#include <QObject>

class Teacher : public QObject
{
    Q_OBJECT
public:
    explicit Teacher(QObject *parent = 0);

signals:
    //自定義信號  寫到signal下
    //返回值是void  只需要聲明  不需要實現(xiàn)
    //可以有參數(shù)民傻，可以重載
    void hungry();

    void hungry(QString FoodName);

public slots:

};

#endif // TEACHER_H

teacher.cpp:

#include "teacher.h"

Teacher::Teacher(QObject *parent) :
    QObject(parent)
{
}

widget.h:

#ifndef WIDGET_H
#define WIDGET_H

#include <QWidget>
#include"teacher.h"
#include"student.h"



namespace Ui {
class Widget;
}

class Widget : public QWidget
{
    Q_OBJECT

public:
    explicit Widget(QWidget *parent = 0);
    ~Widget();

private:
    Ui::Widget *ui;
    Teacher * zt;
    Student * st;

    void ClassOver();

};

#endif // WIDGET_H

widget.cpp :

#include "widget.h"
#include "ui_widget.h"
#include <QPushButton>


//Teacher 類  老師類
//Student 類  學生類

// 下課了  老師發(fā)出一個餓了的信號   學生請吃飯


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

    //創(chuàng)建老師對象
    this ->zt = new Teacher(this);
    //創(chuàng)建學生對象
    this ->st = new Student(this);

//    //老師餓了，學生請吃飯連接
//    //發(fā)個信號
//    connect(zt,&Teacher::hungry,st,&Student::treat);
//    ClassOver();

    //重載時  連接信號和槽 需要定義一個指針
    void(Teacher:: *teacherSingal)(QString)= &Teacher::hungry;
    void(Student:: *studentSlot)(QString) = &Student::treat;
    connect(zt,teacherSingal,st,studentSlot);
    //ClassOver();

    //點擊一個下課按鈕
    QPushButton *btn = new QPushButton("下課",this);
    resize(600,400);


    //點擊按鈕觸發(fā)下課
    //connect(btn,&QPushButton::clicked,this,&Widget::ClassOver);

    //無參數(shù)信號和槽連接
    void(Teacher:: *teacherSingal2)(void)= &Teacher::hungry;
    void(Student:: *studentSlot2)(void) = &Student::treat;
    connect(zt,teacherSingal2,st,studentSlot2);

    //信號連接信號
    connect(btn,&QPushButton::clicked,zt,teacherSingal2);


    //斷開信號
    //disconnect(zt,teacherSingal2,st,studentSlot2);

    //拓展
    //1、信號可以連接信號
    //2、一個信號可以連接多個槽函數(shù)
    //3、多個信號也可以連接一個槽函數(shù)
    //4澈蟆、信號和槽函數(shù)的參數(shù)  一一對應(yīng)的
    //5趟径、信號的參數(shù)個數(shù)可以多余槽函數(shù)參數(shù)的個數(shù)瘪吏，但是有的參數(shù)類型要對應(yīng)


    //版本4的信號和槽連接函數(shù)
    //connect(zt,SIGNAL(hungry()),st,SLOT(treat()));
    //4版本優(yōu)點，參數(shù)直觀蜗巧，缺點：編譯器對類型不做檢測（前后參數(shù)不一樣不做檢測）


// //Lambda表達式知識  匿名函數(shù)
//
//    [=](){
//        btn->setText("aa");
//    };          //沒()只是起到聲明作用掌眠；

//    [=](){
//        btn->setText("aa");
//    }();        //有()才會執(zhí)行

    //mutable關(guān)鍵字永續(xù)修飾值傳遞的變量,修改的時拷貝,而不是值,例子沒寫



    //利用lambda表達式實現(xiàn)點擊按鈕 關(guān)閉窗口

    QPushButton *btn2 = new QPushButton(this);
    btn2->setText("關(guān)閉窗口");
    btn2->move(100,0);

    //connect(btn2,&QPushButton::clicked,this,&Widget::close);

    connect(btn2,&QPushButton::clicked,this,[=](){          //若用lambda表達式連接  若第三個參數(shù)是this可以省略
        //this->close();
        emit zt->hungry("宮保雞丁");
        btn2->setText("bye!");

    });











}

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

void Widget::ClassOver()
{
   // emit zt->hungry();
    emit zt->hungry("宮保雞丁");
}