Cocos2dx引擎10-事件派发

it2025-10-02  6

本文介绍Cocos2dx事件(以下简称Event)处理机制中的事件分发模块,在Event发生后,进过一系列处理,最后将会分发Event;

 

1、dispatchEvent& dispatchTouchEvent方法

voidEventDispatcher::dispatchEvent(Event* event) { if (!_isEnabled) return; updateDirtyFlagForSceneGraph(); DispatchGuard guard(_inDispatch); if (event->getType() ==Event::Type::TOUCH) { dispatchTouchEvent(static_cast<EventTouch*>(event)); return; } auto listenerID = __getListenerID(event); sortEventListeners(listenerID); auto iter = _listenerMap.find(listenerID); if (iter != _listenerMap.end()) { auto listeners = iter->second; auto onEvent =[&event](EventListener* listener) -> bool{ event->setCurrentTarget(listener->getAssociatedNode()); listener->_onEvent(event); return event->isStopped(); }; dispatchEventToListeners(listeners,onEvent); } updateListeners(event); }

在dispatchEvent方法中:

(1)  推断分发Event机制是否使能

(2)  更新脏数据标志

(3)  分发触摸Event

(4)  分发其它类型Event

 

voidEventDispatcher::dispatchTouchEvent(EventTouch* event) { sortEventListeners(EventListenerTouchOneByOne::LISTENER_ID); sortEventListeners(EventListenerTouchAllAtOnce::LISTENER_ID); auto oneByOneListeners =getListeners(EventListenerTouchOneByOne::LISTENER_ID); auto allAtOnceListeners =getListeners(EventListenerTouchAllAtOnce::LISTENER_ID); if (nullptr == oneByOneListeners &&nullptr == allAtOnceListeners) return; bool isNeedsMutableSet = (oneByOneListeners&& allAtOnceListeners); const std::vector<Touch*>&originalTouches = event->getTouches(); std::vector<Touch*>mutableTouches(originalTouches.size()); std::copy(originalTouches.begin(),originalTouches.end(), mutableTouches.begin()); if (oneByOneListeners) { auto mutableTouchesIter =mutableTouches.begin(); auto touchesIter =originalTouches.begin(); for (; touchesIter !=originalTouches.end(); ++touchesIter) { bool isSwallowed = false; auto onTouchEvent =[&](EventListener* l) -> bool { .... }; dispatchEventToListeners(oneByOneListeners, onTouchEvent); if (event->isStopped()){ return; } if (!isSwallowed) ++mutableTouchesIter; } } if (allAtOnceListeners &&mutableTouches.size() > 0) { auto onTouchesEvent =[&](EventListener* l) -> bool{ .... }; dispatchEventToListeners(allAtOnceListeners, onTouchesEvent); if (event->isStopped()){ return; } } updateListeners(event); }

在dispatchTouchEvent方法中:

(1) 对单指点击&多指点击EventListener列表进行排序;当然排序算法中首先推断眼下EventListener列表是否为脏数据,假设是脏数据,则进行排序;排序的具体细节以下会具体讲述

(2) 获取单指点击&多指点击EventListener列表,并推断EventListener是否为空

(3) 获取Event信息

(4) 若单指点击EventListener列表不为空,则分发单指点击Event

(5) 若多指点击EventListener列表不为空,则分发多指点击Event

(6) 更新EventListener列表状态

 

2、dispatchTouchEvent 方法中EvnetListener排序sortEventListeners

在dispatchTouchEvent方法中使用了sortEventListeners方法对EventListener列表进行排序,以下将具体解说该方法;

voidEventDispatcher::sortEventListeners(const EventListener::ListenerID&listenerID) { DirtyFlag dirtyFlag = DirtyFlag::NONE; auto dirtyIter =_priorityDirtyFlagMap.find(listenerID); if (dirtyIter !=_priorityDirtyFlagMap.end()){ dirtyFlag = dirtyIter->second; } if (dirtyFlag != DirtyFlag::NONE) { dirtyIter->second = DirtyFlag::NONE; if ((int)dirtyFlag &(int)DirtyFlag::FIXED_PRIORITY) { sortEventListenersOfFixedPriority(listenerID); } if ((int)dirtyFlag &(int)DirtyFlag::SCENE_GRAPH_PRIORITY) { auto rootNode =Director::getInstance()->getRunningScene(); if (rootNode) { sortEventListenersOfSceneGraphPriority(listenerID, rootNode); }else{ dirtyIter->second =DirtyFlag::SCENE_GRAPH_PRIORITY; } } } }

在sortEventListeners方法中:

(1)  在脏数据列表中查找该listenerID的EventListener是否存在脏数据,若不存在脏数据则不须要排序,退出该方法;若存在脏数据,则进行排序

(2)  针对优先级不等于0的EventListener列表进行排序

(3)  针对优先级等于0的EventListener列表进行排序

 

以下为优先级不等于0的EventListener列表排序方法:

voidEventDispatcher::sortEventListenersOfFixedPriority(constEventListener::ListenerID& listenerID) { auto listeners = getListeners(listenerID); if (listeners == nullptr) return; auto fixedListeners =listeners->getFixedPriorityListeners(); if (fixedListeners == nullptr) return; std::sort(fixedListeners->begin(),fixedListeners->end(), [](const EventListener* l1, const EventListener* l2){ return l1->getFixedPriority() <l2->getFixedPriority(); }); intindex = 0; for (auto& listener : *fixedListeners){ if (listener->getFixedPriority()>= 0) break; ++index; } listeners->setGt0Index(index); }

在sortEventListenersOfFixedPriority方法中:

(1) 依据ID获取EventListener列表,并推断列表是否为空

(2) 获取EventListener列表中优先级不等于0的EventListener列表_fixedListeners

(3) 使用STL中sort方法对_fixedListeners方法从小到大排序

(4) 统计fixedListeners类表中优先级数值小于0的EventListener的个数

从排序的方法能够得知,高优先级(数值越小优先级越高)EventListener先运行;若优先级同样,先注冊的EventListener先运行

 

以下为优先级等于0的EventListener列表排序方法:

voidEventDispatcher::sortEventListenersOfSceneGraphPriority(constEventListener::ListenerID& listenerID, Node* rootNode) { auto listeners = getListeners(listenerID); if (listeners == nullptr) return; auto sceneGraphListeners =listeners->getSceneGraphPriorityListeners(); if (sceneGraphListeners == nullptr) return; _nodePriorityIndex = 0; _nodePriorityMap.clear(); visitTarget(rootNode, true); std::sort(sceneGraphListeners->begin(),sceneGraphListeners->end(), [this](const EventListener* l1, constEventListener* l2) { return_nodePriorityMap[l1->getAssociatedNode()] > _nodePriorityMap[l2->getAssociatedNode()]; }); }

在sortEventListenersOfSceneGraphPriority方法中:

(1) 依据ID获取EventListener列表,并推断列表是否为空

(2) 获取EventListener列表中优先级等于0的EventListener列表_sceneGraphListeners

(3) 使用_globalZOrder值对该Scene下的Node排序

(4) 依据EventListener相应Node的_globalZOrder值从大到小将_sceneGraphListeners列表排序

 

3、dispatchTouchEvent 方法中dispatchEventToListeners方法

voidEventDispatcher::dispatchEventToListeners(EventListenerVector* listeners, conststd::function<bool(EventListener*)>& onEvent) { bool shouldStopPropagation = false; auto fixedPriorityListeners =listeners->getFixedPriorityListeners(); auto sceneGraphPriorityListeners =listeners->getSceneGraphPriorityListeners(); ssize_t i = 0; if (fixedPriorityListeners) { if(!fixedPriorityListeners->empty()){ for (; i <listeners->getGt0Index(); ++i) { auto l =fixedPriorityListeners->at(i); if (l->isEnabled()&& !l->isPaused() && l->isRegistered() &&onEvent(l)) { shouldStopPropagation =true; break; } } } } if (sceneGraphPriorityListeners) { if (!shouldStopPropagation) { for (auto& l :*sceneGraphPriorityListeners) { if (l->isEnabled()&& !l->isPaused() && l->isRegistered() &&onEvent(l)) { shouldStopPropagation =true; break; } } } } if (fixedPriorityListeners) { if (!shouldStopPropagation) { ssize_t size =fixedPriorityListeners->size(); for (; i < size; ++i) { auto l =fixedPriorityListeners->at(i); if (l->isEnabled()&& !l->isPaused() && l->isRegistered() &&onEvent(l)) { shouldStopPropagation = true; break; } } } } }

在dispatchEventToListeners函数中:

(1) 获取_fixedListeners&_sceneGraphListeners列表

(2) 当_fixedListeners不为空时;运行_fixedListeners类表中EventToListener处理

(3) 当_sceneGraphListeners不为空时;运行_sceneGraphListeners类表中EventToListener处理

在_fixedListeners类表中EventToListener处理中,优先级小于0的是不运行的处理方法的;EventToListener的处理方法是通过參数传递过来的匿名函数;该匿名函数的实现以下会继续讲述

 

4、dispatchTouchEvent 方法中单点匿名方法onTouchEvent

auto onTouchEvent =[&](EventListener* l) -> bool { EventListenerTouchOneByOne* listener =static_cast<EventListenerTouchOneByOne*>(l); if (!listener->_isRegistered) returnfalse; event->setCurrentTarget(listener->_node); bool isClaimed = false; std::vector<Touch*>::iteratorremovedIter; EventTouch::EventCode eventCode =event->getEventCode(); if (eventCode ==EventTouch::EventCode::BEGAN) { if (listener->onTouchBegan) { isClaimed =listener->onTouchBegan(*touchesIter, event); if (isClaimed &&listener->_isRegistered) { listener->_claimedTouches.push_back(*touchesIter); } } } else if (listener->_claimedTouches.size()> 0 && ((removedIter =std::find(listener->_claimedTouches.begin(),listener->_claimedTouches.end(), *touchesIter)) != listener->_claimedTouches.end())){ isClaimed = true; switch (eventCode) { case EventTouch::EventCode::MOVED: if (listener->onTouchMoved) { listener->onTouchMoved(*touchesIter,event); } break; case EventTouch::EventCode::ENDED: if (listener->onTouchEnded) { listener->onTouchEnded(*touchesIter,event); } if (listener->_isRegistered) { listener->_claimedTouches.erase(removedIter); } break; caseEventTouch::EventCode::CANCELLED: if (listener->onTouchCancelled){ listener->onTouchCancelled(*touchesIter,event); } if (listener->_isRegistered) { listener->_claimedTouches.erase(removedIter); } break; default: CCASSERT(false, "Theeventcode is invalid."); break; } } if (event->isStopped()){ updateListeners(event); return true; } if (isClaimed &&listener->_isRegistered && listener->_needSwallow) { if (isNeedsMutableSet) { mutableTouchesIter =mutableTouches.erase(mutableTouchesIter); isSwallowed = true; } return true; } return false; };

在匿名方法onTouchEvent中:

(1) 将传递參数强制转换成EventListenerTouchOneByOne类型,并推断是否为空

(2) 获取触摸(Win32下为鼠标点击\拖动)Event类型

(3) 推断Event类型是BEGAN时

            a)  调用EventListener在注冊时指定的onTouchBegan,并获取返回值

            b)  若返回值是true,将该Event的Touch信息放入_claimedTouches中

(4) 推断Event类型不是BEGAN时

            a)  _claimedTouches的内容不为空,在_claimedTouches中有该Event的Touch信息

            b)  若Event类型是MOVED,调用EventListener在注冊时指定的onTouchMoved

            c)  若Event类型是ENDED,调用EventListener在注冊时指定的onTouchEnded

            d)  若Event类型是CANCELLED,调用EventListener在注冊时指定的onTouchCancelled

            e)  将该Event的Touch信息从_claimedTouches中移除

(5) 若该Event被停止,更新EventListener列表

(6) 若在onTouchBegan返回值为true,而且_needSwallow被设置为true时,将当前Event从多点触摸Event列表中移除

在该匿名方法中,onTouchBegan的返回值非常重要,他关注着兴许其它触摸操作(onTouchMoved\onTouchEnded\onTouchCancelled)是否运行,关注则_needSwallow标志是否生效;

 

5、dispatchTouchEvent 方法中多点的匿名方法onTouchEvent

auto onTouchesEvent= [&](EventListener* l) -> bool{ EventListenerTouchAllAtOnce* listener =static_cast<EventListenerTouchAllAtOnce*>(l); if (!listener->_isRegistered) returnfalse; event->setCurrentTarget(listener->_node); switch (event->getEventCode()) { case EventTouch::EventCode::BEGAN: if (listener->onTouchesBegan) { listener->onTouchesBegan(mutableTouches,event); } break; case EventTouch::EventCode::MOVED: if (listener->onTouchesMoved) { listener->onTouchesMoved(mutableTouches,event); } break; case EventTouch::EventCode::ENDED: if (listener->onTouchesEnded) { listener->onTouchesEnded(mutableTouches,event); } break; case EventTouch::EventCode::CANCELLED: if (listener->onTouchesCancelled){ listener->onTouchesCancelled(mutableTouches,event); } break; default: CCASSERT(false, "The eventcodeis invalid."); break; } if (event->isStopped()){ updateListeners(event); return true; } return false; };

在匿名方法onTouchEvent中:

(1)  将传递參数强制转换成EventListenerTouchAllAtOnce类型,并推断是否为空

(2)  获取触摸(Win32下为鼠标点击\拖动)Event类型

(3)  若Event类型为BEGAN时,调用EventListener在注冊时指定的onTouchBegan方法

(4)  若Event类型为MOVED时,调用EventListener在注冊时指定的onTouchesMoved方法

(5)  若Event类型为ENDED时,调用EventListener在注冊时指定的onTouchesEnded方法

(6)  若Event类型为CANCELLED时,调用EventListener在注冊时指定的onTouchesCancelled方法

(7)  若该Event被停止,更新EventListener列表

转载于:https://www.cnblogs.com/bhlsheji/p/4278931.html

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