Qt使用信号槽模拟全局广播
Qt的信号槽很好用，可以轻松的对代码解耦，现在我不想在类里面声明信号槽，也不想写Q_OBJECT，因此有了以下的方式模拟一个全局广播，通过一个全局的实例（单例）发送接收数据
//CGlobalBroadcast.h
#pragma once
#include 注册全局广播实例
CGlobalBroadcast::Install(parent);
在A类中发送广播
struct StructA {
int a;
QString b;
};
Q_DECLARE_METATYPE(StructA);
void A::sendEvent(){
//没有参数的通知
CGlobalBroadcast::PostEvent(BroadcastEvent::CUSTOM_EVENT_VOID);
//发送1个QString
CGlobalBroadcast::PostEvent(BroadcastEvent::CUSTOM_EVENT_VARIANT, "hello B!");
//发送1个StructA
StructA structA;
CGlobalBroadcast::PostEvent(BroadcastEvent::CUSTOM_EVENT_VARIANT, QVariant::fromValue(structA));
//发送一堆数据
QVariantList data;
data << 1;
data << "abc";
CGlobalBroadcast::PostEvent(BroadcastEvent::CUSTOM_EVENT_VARIANT_LIST, data);
}
在B类中接收广播
void B::receiverEvent(){
//接收没有参数的通知
CGlobalBroadcast::RegisterEvent(BroadcastEvent::CUSTOM_EVENT_VOID, [&]() {
//do something...
});
//接收A发送的QString
CGlobalBroadcast::RegisterEvent(BroadcastEvent::CUSTOM_EVENT_VARIANT, [&](QVariant data) {
auto str = data.toString();
//do something...
});
//接收A发送的结构体
CGlobalBroadcast::RegisterEvent(BroadcastEvent::CUSTOM_EVENT_VARIANT, [&](QVariant data) {
auto structA = data.value<StructA>();
//do something...
});
//接收A发送的一堆数据
CGlobalBroadcast::RegisterEvent(BroadcastEvent::CUSTOM_EVENT_VARIANT_LIST, [&](QVariantList data) {
auto dataInt = data.at(0).toInt();
auto dataStr = data.at(1).toString();
//do something...
});
}
用起来很爽，发送和接收都不用connect了，甚至不用继承QObject，A类和B类相隔十万八千里，只要都包含CGlobalBroadcast.h就可以传递数据，不同的消息可以通过消息ID区分，而且B看心情接收不接收消息，B和另一个C也可以接收相同的消息，但是…由于添加消息写在头文件里，每添加1个消息ID后，所有用到CGlobalBroadcast的cpp得全部重新编译一次。
改进
主要解决上述1个问题：由于消息的传递是通过1个实例进行的，在同一个线程下的接收函数发送频率太高会发生阻塞。由此将CGlobalBroadcast做成模板基类，可以实现多个消息发送类，让定义消息分开
定义模板基类CGlobalBroadcastImpl.h
#pragma once
#include 重新定义CGlobalBroadcast，使用方法跟原来一样
//CGlobalBroadcast.h
#pragma once
#include "CGlobalBroadcastImpl.h"
//添加消息Id
struct BroadcastEvent {
enum Event_Void {
CUSTOM_EVENT_VOID = 0,
};
enum Event_Variant {
CUSTOM_EVENT_VARIANT = 0,
};
enum Event_Variant_List {
CUSTOM_EVENT_VARIANT_LIST = 0,
};
};
class CGlobalBroadcast : public CGlobalBroadcastImpl<CGlobalBroadcast, BroadcastEvent> {
Q_OBJECT
public:
CGlobalBroadcast(QObject* parent) : CGlobalBroadcastImpl(parent) {
installFuncVoid();
installFuncVariant();
installFuncVariantList();
}
private:
void installFuncVoid() override;
void installFuncVariant() override;
void installFuncVariantList() override;
//定义消息信号
signals:
//function void
F_VOID(custom_event_void);
//function variant
F_VARIANT(custom_event_variant);
//function variant list
F_VARIANT_LIST(custom_event_variant_list);
};
//CGlobalBroadcast.cpp
#include "CGlobalBroadcast.h"
CGlobalBroadcast* CGlobalBroadcast::globalBroadcast = nullptr;
void CGlobalBroadcast::installFuncVoid() {
funcMap_void.insert(BroadcastEvent::CUSTOM_EVENT_VOID, &CGlobalBroadcast::custom_event_void);
}
void CGlobalBroadcast::installFuncVariant() {
funcMap_variant.insert(BroadcastEvent::CUSTOM_EVENT_VARIANT, &CGlobalBroadcast::custom_event_variant);
}
void CGlobalBroadcast::installFuncVariantList() {
funcMap_variant_list.insert(BroadcastEvent::CUSTOM_EVENT_VARIANT_LIST, &CGlobalBroadcast::custom_event_variant_list);
}
demo工程下载