Qt C++ Observer模式（发布者-订阅者）

最新推荐文章于 2024-08-15 10:28:41 发布

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这篇博客介绍了如何在Qt C++中实现Observer模式，通过CSubjects和CObserver类展示了发布者-订阅者的设计，详细解释了CConServerA和CConServerB两个观察者的更新方法及其交互过程。

observer.h

#pragma once

#include <QDebug>

class CObserver;

class CSubjects
{
public:
CSubjects(){}
virtual ~CSubjects(){};
void attatch(CObserver *obj){m_lstObserver.append(obj);}
void detatch(CObserver *obj){m_lstObserver.removeAll(obj);}

void notify();

void setState(const QString &state){m_state = state;}
QString getState() const{return m_state;}

private:
QString m_state;
QList<CObserver *> m_lstObserver;
};

class CObserver
{
public:
virtual ~CObserver(){}
virtual void update(CSubjects *sub) = 0;
protected:
CObserver(){}
QString m_server;
};

class CConServerA : public CObserver
{
public:
CConServerA(CSubjects *sub):m_sub(sub){m_sub->attatch(this);}
~CConServerA(){m_sub->detatch(this);delete m_sub;}
void update(CSubjects *sub);

private:
CSubjects *m_sub;
};

class CConServerB : public CObserver
{
public:
CConServerB(CSubjects *sub):m_sub(sub){m_sub->attatch(this);}
~CConServerB(){m_sub->detatch(this);delete m_sub;}
void update(CSubjects *sub);
private:
CSubjects *m_sub;
};

observer.cpp

#include "observer.h"

void CSubjects::notify()
{
QListIterator<CObserver *> iter(m_lstObserver);
while(iter.hasNext())
{
CObserver *server = iter.next();
server->update(this);
}
}

void CConServerA::update(CSubjects *sub)
{
m_server = sub->getState();
qDebug() << m_server;
}

void CConServerB::update(CSubjects *sub)
{
m_server = sub->getState();
qDebug() << m_server;
}

main.cpp

#include <QApplication>
#include "observer.h"

int main(int argc,char **argv)
{
QApplication app(argc,argv);
//发布者
CSubjects *subject = new CSubjects;
//订阅者
CObserver *serverA = new CConServerA(subject);
CObserver *serverB = new CConServerB(subject);

subject->setState("jiji");
//subject->notify();
//serverA->update(subject);

return app.exec();
}