QT的信号和槽函数的使用(一）

一，信号的使用

语法：

参数解释：

1. sender：发出信号的对象
2. signal：发送对象发出的信号
3. receiver：接收信号的对象
4. slot：接收对象在接收到信号之后所需要调用的函数（槽函数）
   自带信号的槽函数的使用案例

  //第一个参数是:按键   第二参数是：处理的点击事件，    //第三个参数接收到事件的处理的人    //第四个参数处理事件    connect(ui->pushButton, &QPushButton::clicked, this, &QMainWindow::close);

二，自定义的信号处理事件

1. newspaper.h头文件

#ifndef NEWSPAPER_H#define NEWSPAPER_H#include <QObject>class NewsPaper : public QObject{    Q_OBJECTpublic:    explicit NewsPaper(QObject *parent = 0);    //发送信令    void sendSignal3();signals:    //信令操作    void hasNewsPaper();    void hasNewsPaper(QString name);public slots:};#endif // NEWSPAPER_H

2.newspaper.cpp实现

#include "newspaper.h"NewsPaper::NewsPaper(QObject *parent) : QObject(parent){}void NewsPaper::sendSignal3(){    //发送自定义信令    emit hasNewsPaper();     emit hasNewsPaper("sdlkfj");}

3.Reader.h头文件

#ifndef READER_H#define READER_H#include <QObject>class Reader : public QObject{    Q_OBJECTpublic:    explicit Reader(QObject *parent = 0);    //信令处理函数， 槽函数    void buyNewsPaper3();    void buyNewsPaper3(QString name);signals:public slots:};#endif // READER_H

4.实现

#include "reader.h"#include <QDebug>Reader::Reader(QObject *parent) : QObject(parent){}void Reader::buyNewsPaper3(){    qDebug() << "songli" ;}void Reader::buyNewsPaper3(QString name){    qDebug() << "songli name :" << name  ;}

测试：

#include "mywidget.h"#include "ui_mywidget.h"#include "newspaper.h"#include "reader.h"MyWidget::MyWidget(QWidget *parent) :    QWidget(parent),    ui(new Ui::MyWidget){    ui->setupUi(this);    NewsPaper* newsPaper = new NewsPaper(this);    Reader* reader = new Reader(this);    connect(ui->pushButton, &QPushButton::clicked, newsPaper, &NewsPaper::sendSignal3);    void(NewsPaper::*myfunc)(QString) = &NewsPaper::hasNewsPaper;    void(Reader::*myRead)(QString) = &Reader::buyNewsPaper3;    connect(newsPaper, myfunc, reader, myRead);}MyWidget::~MyWidget(){    delete ui;}

三，总结

QT的信令就是IOC控制反转的实现