自定义信号和槽

来源：互联网发布：什么行业需要网络推广编辑：程序博客网时间：2024/06/05 05:42

发送者和接收者都需要是QObject的子类（当然，槽函数是全局函数、Lambda 表达式等无需接收者的时候除外）；

使用 signals 标记信号函数，信号是一个函数声明，返回 void，不需要实现函数代码；

槽函数是普通的成员函数，作为成员函数，会受到 public、private、protected 的影响；
使用 emit 在恰当的位置发送信号；
使用QObject::connect()函数连接信号和槽。



//!!! Qt4
#include <QObject>
 
////////// newspaper.h
classNewspaper:publicQObject
{
    Q_OBJECT
public:
    Newspaper(constQString&name):
        m_name(name)
    {
    }
 
 
    voidsend()const
    {
        emitnewPaper(m_name);
    }
 
signals:
    voidnewPaper(constQString&name)const;
 
private:
    QStringm_name;
};
 
////////// reader.h
#include <QObject>
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//!!! Qt4
#include <QObject>
 
////////// newspaper.h
classNewspaper:publicQObject
{
    Q_OBJECT
public:
    Newspaper(constQString&name):
        m_name(name)
    {
    }
 
    voidsend()const
    {
        emitnewPaper(m_name);
    }
 
signals:
    voidnewPaper(constQString&name)const;
 
private:
    QStringm_name;
};
 
////////// reader.h
#include <QObject>
#include <QDebug>
 
classReader:publicQObject
{
    Q_OBJECT
public:
    Reader(){}
 
publicslots:
    voidreceiveNewspaper(constQString&name)const
    {
        qDebug()<<"Receives Newspaper: "<<name;
    }
};
 
////////// main.cpp
#include <QCoreApplication>
 
#include "newspaper.h"
#include "reader.h"
 
intmain(intargc,char*argv[])
{
    QCoreApplicationapp(argc,argv);
 
    Newspapernewspaper("Newspaper A");
    Readerreader;
    QObject::connect(&newspaper,SIGNAL(newPaper(QString)),
                    &reader,    SLOT(receiveNewspaper(QString)));
    newspaper.send();
 
    returnapp.exec();
}

发送者和接收者都需要是QObject的子类（当然，槽函数是全局函数、Lambda 表达式等无需接收者的时候除外）；
使用 signals 标记信号函数，信号是一个函数声明，返回 void，不需要实现函数代码；
槽函数是普通的成员函数，作为成员函数，会受到 public、private、protected 的影响；
使用 emit 在恰当的位置发送信号；
使用QObject::connect()函数连接信号和槽。
<QDebug>
 
classReader:publicQObject
{
    Q_OBJECT
public:
    Reader(){}
 
publicslots:
    voidreceiveNewspaper(constQString&name)const
    {
        qDebug()<<"Receives Newspaper: "<<name;
    }
};
 
////////// main.cpp
#include <QCoreApplication>
 
#include "newspaper.h"
#include "reader.h"
 
intmain(intargc,char*argv[])
{
    QCoreApplicationapp(argc,argv);
 
    Newspapernewspaper("Newspaper A");
    Readerreader;
    QObject::connect(&newspaper,SIGNAL(newPaper(QString)),
                    &reader,    SLOT(receiveNewspaper(QString)));
    newspaper.send();
 
    returnapp.exec();
}

//!!! Qt4
#include <QObject>
 
////////// newspaper.h
classNewspaper:publicQObject
{
    Q_OBJECT
public:
    Newspaper(constQString&name):
        m_name(name)
    {
    }
 
    voidsend()const
    {
        emitnewPaper(m_name);
    }
 
signals:
    voidnewPaper(constQString&name)const;
 
private:
    QStringm_name;
};
 
////////// reader.h
#include <QObject>
#include <QDebug>
 
classReader:publicQObject
{
    Q_OBJECT
public:
    Reader(){}
 
publicslots:
    voidreceiveNewspaper(constQString&name)const
    {
        qDebug()<<"Receives Newspaper: "<<name;
    }
};
 
////////// main.cpp
#include <QCoreApplication>
 
#include "newspaper.h"
#include "reader.h"
 
intmain(intargc,char*argv[])
{
    QCoreApplicationapp(argc,argv);
 
    Newspapernewspaper("Newspaper A");
    Readerreader;
    QObject::connect(&newspaper,SIGNAL(newPaper(QString)),
                    &reader,    SLOT(receiveNewspaper(QString)));
    newspaper.send();
 
    returnapp.exec()<span class="crayon-sy" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit !important; font-stretch: inherit; font-size: inh

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