C++如何实现事件驱动 C++事件驱动编程的实现方式

#include <iostream>
#include <vector>
#include <functional>

// 事件类型
enum class EventType {
    ButtonClicked,
    DataReceived
};

// 事件基类
class Event {
public:
    EventType type;
    Event(EventType t) : type(t) {}
};

// ButtonClick事件
class ButtonClickEvent : public Event {
public:
    ButtonClickEvent() : Event(EventType::ButtonClicked) {}
};

// DataReceived事件
class DataReceivedEvent : public Event {
public:
    DataReceivedEvent(std::string data) : Event(EventType::DataReceived), data_(data) {}
    std::string data() const { return data_; }
private:
    std::string data_;
};


// 事件监听器接口
class EventListener {
public:
    virtual void onEvent(Event* event) = 0;
};

// 事件源 (Subject)
class EventSource {
public:
    void addListener(EventListener* listener, EventType type) {
        listeners_[type].push_back(listener);
    }

    void removeListener(EventListener* listener, EventType type) {
        // 移除监听器，这里简化了实现
    }

protected:
    void fireEvent(Event* event) {
        auto& l = listeners_[event->type];
        for (EventListener* listener : l) {
            listener->onEvent(event);
        }
    }

private:
    std::unordered_map<EventType, std::vector<EventListener*>> listeners_;
};

// 示例监听器
class MyButton : public EventSource {
public:
    void click() {
        fireEvent(new ButtonClickEvent());
    }
};

class MyDataReceiver : public EventSource {
public:
    void receiveData(const std::string& data) {
        fireEvent(new DataReceivedEvent(data));
    }
};

class MyEventHandler : public EventListener {
public:
    void onEvent(Event* event) override {
        if (event->type == EventType::ButtonClicked) {
            std::cout << "Button Clicked!" << std::endl;
        } else if (event->type == EventType::DataReceived) {
            DataReceivedEvent* dataEvent = static_cast<DataReceivedEvent*>(event);
            std::cout << "Data Received: " << dataEvent->data() << std::endl;
        }
        delete event; // 释放事件内存
    }
};

int main() {
    MyButton button;
    MyDataReceiver receiver;
    MyEventHandler handler;

    button.addListener(&handler, EventType::ButtonClicked);
    receiver.addListener(&handler, EventType::DataReceived);

    button.click();
    receiver.receiveData("Hello, Event-Driven World!");

    return 0;
}