Qt實現全局觀察者模式(多層窗體之間直接傳遞消息)
近來做項目發現,多個窗體之間要通信真的好麻煩,比如:A調出B,B調出C,那麼C給A發消息,那就得經過B轉發才能實現。對於兩三層窗體,這種方法還可以接受,但嵌套太多就有點煩人了。
基於這個原因,那麼要實現的東西就很清楚了,有一個全局類,去直接綁定信號槽關係,在需要觸發的時候,通過這個全局類的函數,去相應的觸發一下,就可以實現直連通信了。
globalObserver.h
#ifndef GLOBALOBSERVER_H
#define GLOBALOBSERVER_H
#include <QObject>
#include "obesrverApater.h"
struct relationData
{
QString type;
QObject *reciver;
obesrverApater *obesrverApater;
};
class globalObserver : public QObject
{
Q_OBJECT
public:
//因爲是全局只有一個,所以直接單例模式
static globalObserver* getGlobalObserver();
static void release();
static globalObserver *m_pInst;
//綁定
void attach(const QString type, QObject *reciver, const char *method);
//解綁
void detach(const QString type, const QObject* reciver);
//觸發
void notify(const QString type);
private:
explicit globalObserver(QObject *parent = 0);
~globalObserver();
private:
QList<relationData*> m_oRelationList;
};
#endif // GLOBALOBSERVER_H
- relationData:結構體,保存對應關係;
- relationData::type:字符串類型,就相當於信號的唯一標識符
- relationData::reciver:信號接收者,保存這個變量主要實在detach的時候去使用。
- relationData::obesrverApater;這個類的作用就很重要了,具體看該類的詳解。
obesrverApater.h
#ifndef OBESRVERAPATER_H
#define OBESRVERAPATER_H
#include <QObject>
class obesrverApater;
//工廠,方便構造對象
class obesrverApaterFactory
{
public:
static obesrverApaterFactory *getInst();
static void realese();
static obesrverApaterFactory* inst;
obesrverApater* createObesrverApater();
private:
obesrverApaterFactory()
{}
};
//中間層,用來連接信號槽
class obesrverApater : public QObject
{
Q_OBJECT
public:
explicit obesrverApater(QObject *parent = 0);
signals:
void notify();
};
#endif // OBESRVERAPATER_H
- obesrverApater:該類的主要目的是attach的時候,將傳進來的槽函數直接綁定到改類的notify信號,因爲傳進來的槽函數,要想在觸發時去掉用拿不到函數名稱,所以藉助中間層直接綁定,在觸發的時候直接去觸發中間層的信號,就可達到目的。
- obesrverApaterFactory:創建中間層的工廠,方便類創建。 -
接下來就主要看看具體函數的實現了:
- 工廠類去創建中間層對象實體
obesrverApater *obesrverApaterFactory::createObesrverApater()
{
return new obesrverApater();
}
- 觀察者綁定函數實現
void globalObserver::attach(const QString type, QObject *reciver, const char *method)
{
obesrverApater *oA = obesrverApaterFactory::getInst()->createObesrverApater();
connect(oA, SIGNAL(notify()), reciver, method);
relationData *data = new relationData();
data->type = type;
data->reciver = reciver;
data->obesrverApater = oA;
m_oRelationList.append(data);
}
- 觀察者解綁函數實現
void globalObserver::detach(const QString type, const QObject *reciver)
{
QList<relationData*>::iterator iter = m_oRelationList.begin();
while (iter != m_oRelationList.end())
{
if ((*iter)->type.compare(type) == 0 && (*iter)->reciver == reciver)
{
relationData *data = *iter;
m_oRelationList.removeOne((*iter));
delete data->obesrverApater;
delete data;
return;
}
iter++;
}
}
- 觀察者觸發函數實現
void globalObserver::notify(const QString type)
{
QList<relationData*>::iterator iter = m_oRelationList.begin();
while (iter != m_oRelationList.end())
{
if ((*iter)->type.compare(type) == 0)
{
emit (*iter)->obesrverApater->notify();
}
iter++;
}
}
- 程序結束時別忘了銷燬
globalObserver::~globalObserver()
{
//釋放列表數據
QList<relationData*>::iterator iter = m_oRelationList.begin();
while (iter != m_oRelationList.end())
{
delete (*iter)->obesrverApater;
delete *iter;
iter++;
}
}
測試:
- 測試代碼
Widget::Widget(QWidget *parent)
: QWidget(parent)
{
globalObserver::getGlobalObserver()->attach("haha", this, SLOT(haha()));
globalObserver::getGlobalObserver()->attach("hehe", this, SLOT(hehe()));
QPushButton *p = new QPushButton("haha", this);
connect(p, SIGNAL(clicked()), this, SLOT(onHaha()));
p->setGeometry(10, 10, 200, 40);
}
Widget::~Widget()
{
globalObserver::getGlobalObserver()->detach("haha", this);
globalObserver::getGlobalObserver()->detach("hehe", this);
}
void Widget::haha()
{
QMessageBox::about(this, "", "haha");
}
void Widget::hehe()
{
QMessageBox::about(this, "", "hehe");
}
void Widget::onHaha()
{
globalObserver::getGlobalObserver()->notify("haha");
}
備註:自己在空閒時間寫的,功能相對簡單,有問題歡迎討論!