源代码版本号来自3.x，转载请注明
cocos2d-x 源代码分析总文件夹
http://blog.csdn.net/u011225840/article/details/31743129
1.继承结构
1.1 结构
1.2.EventDispatcher,EventListener,Event三者的关系
详细的，能够看源代码分析。
2.源代码分析
2.1Event相关
2.1.1 Event
enum class Type
{
TOUCH,
KEYBOARD,
ACCELERATION,
MOUSE,
FOCUS,
CUSTOM
};
Type _type; ///< Event type
bool _isStopped; ///< whether the event has been stopped.
Node* _currentTarget; 2.1.2 EventTouch
enum class EventCode
{
BEGAN,
MOVED,
ENDED,
CANCELLED
};2.1.3 EventCustom
void* _userData; ///< User data
std::string _eventName;有没有似曾相识的感觉，还是一样的key。还是一样的userData（有点不一样。原来是CCObject*）。
2.2 EventListener相关
2.2.1 EventListener
std::function<void(Event*)> _onEvent; /// Event callback function
Type _type; /// Event listener type
ListenerID _listenerID; /// Event listener ID
bool _isRegistered; /// Whether the listener has been added to dispatcher.
int _fixedPriority; // The higher the number, the higher the priority, 0 is for scene graph base priority.
Node* _node; // scene graph based priority
bool _paused; // Whether the listener is paused
bool _isEnabled; // Whether the listener is enabled /** Enables or disables the listener
* @note Only listeners with `enabled` state will be able to receive events.
* When an listener was initialized, it's enabled by default.
* An event listener can receive events when it is enabled and is not paused.
* paused state is always false when it is a fixed priority listener.
*/
inline void setEnabled(bool enabled) { _isEnabled = enabled; };/** Sets paused state for the listener
* The paused state is only used for scene graph priority listeners.
* `EventDispatcher::resumeAllEventListenersForTarget(node)` will set the paused state to `true`,
* while `EventDispatcher::pauseAllEventListenersForTarget(node)` will set it to `false`.
* @note 1) Fixed priority listeners will never get paused. If a fixed priority doesn't want to receive events,
* call `setEnabled(false)` instead.
* 2) In `Node`'s onEnter and onExit, the `paused state` of the listeners which associated with that node will be automatically updated.
*/
inline void setPaused(bool paused) { _paused = paused; };上面两段话。解释了什么时候一个Listener是能够接收事件，什么时候是不能够的。
2.2.2 EventListenerOneByOne
/// Overrides
virtual EventListenerTouchOneByOne* clone() override;
virtual bool checkAvailable() override;
//
public:
std::function<bool(Touch*, Event*)> onTouchBegan;
std::function<void(Touch*, Event*)> onTouchMoved;
std::function<void(Touch*, Event*)> onTouchEnded;
std::function<void(Touch*, Event*)> onTouchCancelled;EventListenerTouchOneByOne* EventListenerTouchOneByOne::clone()
{
//深拷贝
auto ret = new EventListenerTouchOneByOne();
if (ret && ret->init())
{
ret->autorelease();
ret->onTouchBegan = onTouchBegan;
ret->onTouchMoved = onTouchMoved;
ret->onTouchEnded = onTouchEnded;
ret->onTouchCancelled = onTouchCancelled;
ret->_claimedTouches = _claimedTouches;
ret->_needSwallow = _needSwallow;
}
else
{
CC_SAFE_DELETE(ret);
}
return ret;
}bool EventListenerTouchOneByOne::checkAvailable()
{
// EventDispatcher will use the return value of 'onTouchBegan' to determine whether to pass following 'move', 'end'
// message to 'EventListenerTouchOneByOne' or not. So 'onTouchBegan' needs to be set.
//OneByOne仅仅须要onTouchBegan不为空，则能够觉得其是可用的。
if (onTouchBegan == nullptr)
{
CCASSERT(false, "Invalid EventListenerTouchOneByOne!");
return false;
}
return true;
}
什么是可用性，当在dispatcher进行事件分发时，假设一个Listener是不可用的。则不会将该事件分发给他。 std::vector<Touch*> _claimedTouches;
bool _needSwallow;OneByOne的touch是能够设置吞噬属性的。
2.2.3 EventListenerAllAtOnce
std::function<void(const std::vector<Touch*>&, Event*)> onTouchesBegan;
std::function<void(const std::vector<Touch*>&, Event*)> onTouchesMoved;
std::function<void(const std::vector<Touch*>&, Event*)> onTouchesEnded;
std::function<void(const std::vector<Touch*>&, Event*)> onTouchesCancelled;bool EventListenerTouchAllAtOnce::checkAvailable()
{
if (onTouchesBegan == nullptr && onTouchesMoved == nullptr
&& onTouchesEnded == nullptr && onTouchesCancelled == nullptr)
{
CCASSERT(false, "Invalid EventListenerTouchAllAtOnce!");
return false;
}
return true;
}2.3 EventListenerCustom
3. EventDispatcher
3.1 EventListenerVector
class EventListenerVector
{
public:
EventListenerVector();
~EventListenerVector();
size_t size() const;
bool empty() const;
void push_back(EventListener* item);
void clearSceneGraphListeners();
void clearFixedListeners();
void clear();
inline std::vector<EventListener*>* getFixedPriorityListeners() const { return _fixedListeners; };
inline std::vector<EventListener*>* getSceneGraphPriorityListeners() const { return _sceneGraphListeners; };
inline ssize_t getGt0Index() const { return _gt0Index; };
inline void setGt0Index(ssize_t index) { _gt0Index = index; };
private:
std::vector<EventListener*>* _fixedListeners;
std::vector<EventListener*>* _sceneGraphListeners;
ssize_t _gt0Index;
};size_t EventDispatcher::EventListenerVector::size() const
{
//vector内部的size大小是两个list的和
size_t ret = 0;
if (_sceneGraphListeners)
ret += _sceneGraphListeners->size();
if (_fixedListeners)
ret += _fixedListeners->size();
return ret;
}void EventDispatcher::EventListenerVector::push_back(EventListener* listener)
{
//查看listener的priority。假设为0，增加sceneGraphList，否则增加fixedList
if (listener->getFixedPriority() == 0)
{
if (_sceneGraphListeners == nullptr)
{
_sceneGraphListeners = new std::vector<EventListener*>();
_sceneGraphListeners->reserve(100);
}
_sceneGraphListeners->push_back(listener);
}
else
{
if (_fixedListeners == nullptr)
{
_fixedListeners = new std::vector<EventListener*>();
_fixedListeners->reserve(100);
}
_fixedListeners->push_back(listener);
}
}上面两个函数是与一般Vector不一样的地方。须要注意的地方我已经标注了凝视。
3.2 Add操作
3.2.1 sceneGraph类
void EventDispatcher::addEventListenerWithSceneGraphPriority(EventListener* listener, Node* node)
{
CCASSERT(listener && node, "Invalid parameters.");
CCASSERT(!listener->isRegistered(), "The listener has been registered.");
//检查Listener可用性
if (!listener->checkAvailable())
return;
//设置listener相关属性
listener->setAssociatedNode(node);
listener->setFixedPriority(0);
listener->setRegistered(true);
addEventListener(listener);
}3.2.2 fixed类
void EventDispatcher::addEventListenerWithFixedPriority(EventListener* listener, int fixedPriority)
{
CCASSERT(listener, "Invalid parameters.");
//一个事件仅仅能被注冊一次
CCASSERT(!listener->isRegistered(), "The listener has been registered.");
//Fixed类型的事件优先级不能是0
CCASSERT(fixedPriority != 0, "0 priority is forbidden for fixed priority since it's used for scene graph based priority.");
//检查可用性
if (!listener->checkAvailable())
return;
//设置关联属性
listener->setAssociatedNode(nullptr);
listener->setFixedPriority(fixedPriority);
listener->setRegistered(true);
listener->setPaused(false);
addEventListener(listener);
}
3.2.3 custom类
EventListenerCustom* EventDispatcher::addCustomEventListener(const std::string &eventName, const std::function<void(EventCustom*)>& callback)
{
//custom类的事件加入是通过eventName 和 eventcallBack来进行加入的
EventListenerCustom *listener = EventListenerCustom::create(eventName, callback);
//custom的事件优先级被默觉得1
addEventListenerWithFixedPriority(listener, 1);
return listener;
}能够看出，加入函数最后都用到了一个函数addEventListener，以下对其进行剖析（这个函数又用到了其它函数。又。又，又。。
。
。。
。）
3.2.4 addEventListener
void EventDispatcher::addEventListener(EventListener* listener)
{
//假设当前Dispatcher正在进行事件Dispatch，则放到toAddList中。
if (_inDispatch == 0)
{
forceAddEventListener(listener);
}
else
{
// std::vector
_toAddedListeners.push_back(listener);
}
listener->retain();
}3.2.5 forceAddEventListener
void EventDispatcher::forceAddEventListener(EventListener* listener)
{
EventListenerVector* listeners = nullptr;
EventListener::ListenerID listenerID = listener->getListenerID();
//找到该类eventlistener的vector。此处的vector是EventVector
auto itr = _listenerMap.find(listenerID);
//假设没有找到，则须要向map中加入一个pair
if (itr == _listenerMap.end())
{
listeners = new EventListenerVector();
_listenerMap.insert(std::make_pair(listenerID, listeners));
}
else
{
listeners = itr->second;
}
//将该类别listenerpush_back进去（这个函数调用的是EventVector的pushback哦）
listeners->push_back(listener);
//假设优先级是0。则设置为graph。
if (listener->getFixedPriority() == 0)
{
//设置该listenerID的DirtyFlag
//(setDirty函数能够这样理解，每一个ListenerID都有特定的dirtyFlag。每次进行add操作后，都要更新该ID的flag)
setDirty(listenerID, DirtyFlag::SCENE_GRAPH_PRIORITY);
//假设是sceneGraph类的事件。则须要处理两个方面：
//1.将node 与event 关联
//2.假设该node是执行中的。则须要恢复其事件（由于默认的sceneGraph listener的状态时pause）
//添加该listener与node的关联
auto node = listener->getAssociatedNode();
CCASSERT(node != nullptr, "Invalid scene graph priority!");
associateNodeAndEventListener(node, listener);
//恢复node的执行状态
if (node->isRunning())
{
resumeEventListenersForTarget(node);
}
}
else
{
setDirty(listenerID, DirtyFlag::FIXED_PRIORITY);
}
}3.2.6associateNodeAndEventListener
void EventDispatcher::associateNodeAndEventListener(Node* node, EventListener* listener)
{
//将listener与node关联，先从map中找到与该node相关的listener vector
std::vector<EventListener*>* listeners = nullptr;
auto found = _nodeListenersMap.find(node);
if (found != _nodeListenersMap.end())
{
listeners = found->second;
}
else
{
listeners = new std::vector<EventListener*>();
_nodeListenersMap.insert(std::make_pair(node, listeners));
}
//vector内加入该listener，这里的vector 是std::vector
listeners->push_back(listener);
}3.2.7 removeEventListenersForTarget
void EventDispatcher::resumeEventListenersForTarget(Node* target, bool recursive/* = false */)
{
//恢复Node的执行状态
auto listenerIter = _nodeListenersMap.find(target);
if (listenerIter != _nodeListenersMap.end())
{
auto listeners = listenerIter->second;
for (auto& l : *listeners)
{
l->setPaused(false);
}
}
// toAdd List中也要进行恢复
for (auto& listener : _toAddedListeners)
{
if (listener->getAssociatedNode() == target)
{
listener->setPaused(false);
}
}
//将该Node 与 node的child 都放到dirtyNode中，来记录与event相关的node
setDirtyForNode(target);
if (recursive)
{
const auto& children = target->getChildren();
for (const auto& child : children)
{
resumeEventListenersForTarget(child, true);
}
}
}3.3 Remove
3.3.1 removeEventListener
void EventDispatcher::removeEventListener(EventListener* listener)
{
//说在前面，移除一个事件的代价比較大，假设没有必要，请不要无故移除事件。
//删除一个listener的步骤:
if (listener == nullptr)
return;
bool isFound = false;
//lambda函数。函数从std::vector<EventListener*>* listeners 中移除该listener
auto removeListenerInVector = [&](std::vector<EventListener*>* listeners){
if (listeners == nullptr)
return;
//遍历
for (auto iter = listeners->begin(); iter != listeners->end(); ++iter)
{
auto l = *iter;
if (l == listener)
{
//找到后的处理方法，标记状态位，并处理关联Node
CC_SAFE_RETAIN(l);
l->setRegistered(false);
if (l->getAssociatedNode() != nullptr)
{
dissociateNodeAndEventListener(l->getAssociatedNode(), l);
l->setAssociatedNode(nullptr); // NULL out the node pointer so we don't have any dangling pointers to destroyed nodes.
}
//当前没有在分发事件 则直接从listeners中移除该listener（由于标记了状态未。假设此时在分发事件。则会等结束后再移除）
if (_inDispatch == 0)
{
listeners->erase(iter);
CC_SAFE_RELEASE(l);
}
isFound = true;
break;
}
}
};
for (auto iter = _listenerMap.begin(); iter != _listenerMap.end();)
{
//从listenersmap 中遍历全部。拿出全部的vector
auto listeners = iter->second;
auto fixedPriorityListeners = listeners->getFixedPriorityListeners();
auto sceneGraphPriorityListeners = listeners->getSceneGraphPriorityListeners();
//从graphList中寻找。找到后须要更新该listenerID的dirty flag。
removeListenerInVector(sceneGraphPriorityListeners);
if (isFound)
{
// fixed #4160: Dirty flag need to be updated after listeners were removed.
setDirty(listener->getListenerID(), DirtyFlag::SCENE_GRAPH_PRIORITY);
}
//从fixedList中寻找
else
{
removeListenerInVector(fixedPriorityListeners);
if (isFound)
{
setDirty(listener->getListenerID(), DirtyFlag::FIXED_PRIORITY);
}
}
//假设vector在删除后是空的，则须要移除该vector。而且将对应的listenerID从_priorityDirtyFlagMap中移除。
if (iter->second->empty())
{
_priorityDirtyFlagMap.erase(listener->getListenerID());
auto list = iter->second;
iter = _listenerMap.erase(iter);
CC_SAFE_DELETE(list);
}
else
{
++iter;
}
if (isFound)
break;
}
if (isFound)
{
CC_SAFE_RELEASE(listener);
}
//假设在上述过程中未找到。则从toAddList中寻找
else
{
for(auto iter = _toAddedListeners.begin(); iter != _toAddedListeners.end(); ++iter)
{
if (*iter == listener)
{
listener->setRegistered(false);
listener->release();
_toAddedListeners.erase(iter);
break;
}
}
}
}
3.3.2 removeEventListenersForListenerID
void EventDispatcher::removeEventListenersForListenerID(const EventListener::ListenerID& listenerID)
{
auto listenerItemIter = _listenerMap.find(listenerID);
if (listenerItemIter != _listenerMap.end())
{
auto listeners = listenerItemIter->second;
auto fixedPriorityListeners = listeners->getFixedPriorityListeners();
auto sceneGraphPriorityListeners = listeners->getSceneGraphPriorityListeners();
//啊哦 又是一个lambda函数。将std::vector<EventListener*>* listenerVector中的Listener所有移除
auto removeAllListenersInVector = [&](std::vector<EventListener*>* listenerVector){
if (listenerVector == nullptr)
return;
for (auto iter = listenerVector->begin(); iter != listenerVector->end();)
{
//设置要删除的listener状态，清空与其相关的node信息
auto l = *iter;
l->setRegistered(false);
if (l->getAssociatedNode() != nullptr)
{
dissociateNodeAndEventListener(l->getAssociatedNode(), l);
l->setAssociatedNode(nullptr); // NULL out the node pointer so we don't have any dangling pointers to destroyed nodes.
}
if (_inDispatch == 0)
{
iter = listenerVector->erase(iter);
CC_SAFE_RELEASE(l);
}
else
{
++iter;
}
}
};
//两种类型的事件哦
removeAllListenersInVector(sceneGraphPriorityListeners);
removeAllListenersInVector(fixedPriorityListeners);
// Remove the dirty flag according the 'listenerID'.
// No need to check whether the dispatcher is dispatching event.
_priorityDirtyFlagMap.erase(listenerID);
if (!_inDispatch)
{
listeners->clear();
delete listeners;
_listenerMap.erase(listenerItemIter);
}
}
//toAddList 的清理，真可怜，还没来得及进入家门就要被扫地出门了么。。。。
for (auto iter = _toAddedListeners.begin(); iter != _toAddedListeners.end();)
{
if ((*iter)->getListenerID() == listenerID)
{
(*iter)->setRegistered(false);
(*iter)->release();
iter = _toAddedListeners.erase(iter);
}
else
{
++iter;
}
}
}void EventDispatcher::removeEventListenersForType(EventListener::Type listenerType)
{
if (listenerType == EventListener::Type::TOUCH_ONE_BY_ONE)
{
removeEventListenersForListenerID(EventListenerTouchOneByOne::LISTENER_ID);
}
else if (listenerType == EventListener::Type::TOUCH_ALL_AT_ONCE)
{
removeEventListenersForListenerID(EventListenerTouchAllAtOnce::LISTENER_ID);
}
else if (listenerType == EventListener::Type::MOUSE)
{
removeEventListenersForListenerID(EventListenerMouse::LISTENER_ID);
}
else if (listenerType == EventListener::Type::ACCELERATION)
{
removeEventListenersForListenerID(EventListenerAcceleration::LISTENER_ID);
}
else if (listenerType == EventListener::Type::KEYBOARD)
{
removeEventListenersForListenerID(EventListenerKeyboard::LISTENER_ID);
}
else
{
CCASSERT(false, "Invalid listener type!");
}
}void EventDispatcher::removeCustomEventListeners(const std::string& customEventName)
{
removeEventListenersForListenerID(customEventName);
}3.3.3 removeAllEventListeners
void EventDispatcher::removeAllEventListeners()
{
bool cleanMap = true;
std::vector<EventListener::ListenerID> types(_listenerMap.size());
for (const auto& e : _listenerMap)
{
if (_internalCustomListenerIDs.find(e.first) != _internalCustomListenerIDs.end())
{
cleanMap = false;
}
else
{
types.push_back(e.first);
}
}
for (const auto& type : types)
{
removeEventListenersForListenerID(type);
}
if (!_inDispatch && cleanMap)
{
_listenerMap.clear();
}
}3.4 DispatchEvent（核心内容）
ok，让我们静静赞赏源代码吧。
3.4.1 dispatchEvent
void EventDispatcher::dispatchEvent(Event* event)
{
if (!_isEnabled)
return;
//为dirtyNodesVector中的dirtyNode更新Scene Flag。
updateDirtyFlagForSceneGraph();
DispatchGuard guard(_inDispatch);
//特殊touch事件，转到特殊的touch事件处理
if (event->getType() == Event::Type::TOUCH)
{
dispatchTouchEvent(static_cast<EventTouch*>(event));
return;
}
//依据事件的类型。获取事件的ID
auto listenerID = __getListenerID(event);
//依据事件ID，将该类事件进行排序（先响应谁）
sortEventListeners(listenerID);
auto iter = _listenerMap.find(listenerID);
if (iter != _listenerMap.end())
{
auto listeners = iter->second;
//该类事件的lambda函数
auto onEvent = [&event](EventListener* listener) -> bool{
//设置event的target
event->setCurrentTarget(listener->getAssociatedNode());
//调用响应函数
listener->_onEvent(event);
//返回是否已经停止
return event->isStopped();
};
//将该类事件的listeners 和 该类事件的 lambda函数传给该函数
dispatchEventToListeners(listeners, onEvent);
}
//更新该事件相关的listener
updateListeners(event);
}
3.4.2 dispatchEventToListeners
void EventDispatcher::dispatchEventToListeners(EventListenerVector* listeners, const std::function<bool(EventListener*)>& onEvent)
{
bool shouldStopPropagation = false;
auto fixedPriorityListeners = listeners->getFixedPriorityListeners();
auto sceneGraphPriorityListeners = listeners->getSceneGraphPriorityListeners();
//总体操作流程分为三个部分，处理优先级<0，=0,>0三个部分
ssize_t i = 0;
// priority < 0
if (fixedPriorityListeners)
{
CCASSERT(listeners->getGt0Index() <= static_cast<ssize_t>(fixedPriorityListeners->size()), "Out of range exception!");
if (!fixedPriorityListeners->empty())
{
for (; i < listeners->getGt0Index(); ++i)
{
auto l = fixedPriorityListeners->at(i);
// onEvent（l）的操作调用了event的callBack，而且会返回是否停止，假设停止后，则将shouldStopPropagation标记为true
//在其后面的listeners则不会响应到该事件（这里能够看出触摸事件是怎样被吞噬的）
if (l->isEnabled() && !l->isPaused() && l->isRegistered() && onEvent(l))
{
shouldStopPropagation = true;
break;
}
}
}
}
if (sceneGraphPriorityListeners)
{
if (!shouldStopPropagation)
{
// priority == 0, scene graph priority
for (auto& l : *sceneGraphPriorityListeners)
{
if (l->isEnabled() && !l->isPaused() && l->isRegistered() && onEvent(l))
{
shouldStopPropagation = true;
break;
}
}
}
}
if (fixedPriorityListeners)
{
if (!shouldStopPropagation)
{
// priority > 0
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;
}
}
}
}
}
3.4.3 dispatchTouchEvent（3.x版本号的触摸机制）
void EventDispatcher::dispatchTouchEvent(EventTouch* event)
{
//先将EventListeners排序
sortEventListeners(EventListenerTouchOneByOne::LISTENER_ID);
sortEventListeners(EventListenerTouchAllAtOnce::LISTENER_ID);
auto oneByOneListeners = getListeners(EventListenerTouchOneByOne::LISTENER_ID);
auto allAtOnceListeners = getListeners(EventListenerTouchAllAtOnce::LISTENER_ID);
// If there aren't any touch listeners, return directly.
if (nullptr == oneByOneListeners && nullptr == allAtOnceListeners)
return;
//mutableTouches是用来处理allAtOnce的
bool isNeedsMutableSet = (oneByOneListeners && allAtOnceListeners);
//这些touch都来自该事件
const std::vector<Touch*>& originalTouches = event->getTouches();
std::vector<Touch*> mutableTouches(originalTouches.size());
std::copy(originalTouches.begin(), originalTouches.end(), mutableTouches.begin());
//
// process the target handlers 1st
//
if (oneByOneListeners)
{
auto mutableTouchesIter = mutableTouches.begin();
auto touchesIter = originalTouches.begin();
//遍历touches，每个touch都来自于同一个事件
for (; touchesIter != originalTouches.end(); ++touchesIter)
{
bool isSwallowed = false;
//事件处理的lambda函数
auto onTouchEvent = [&](EventListener* l) -> bool { // Return true to break
EventListenerTouchOneByOne* listener = static_cast<EventListenerTouchOneByOne*>(l);
// Skip if the listener was removed.
if (!listener->_isRegistered)
return false;
event->setCurrentTarget(listener->_node);
//claimed代表该listener是否接收了该touch（Began返回true or false）
bool isClaimed = false;
std::vector<Touch*>::iterator removedIter;
//依据eventNode的不同，会调用不同的callBack函数
EventTouch::EventCode eventCode = event->getEventCode();
if (eventCode == EventTouch::EventCode::BEGAN)
{
//调用began
if (listener->onTouchBegan)
{
isClaimed = listener->onTouchBegan(*touchesIter, event);
if (isClaimed && listener->_isRegistered)
{
//返回true后 将该touch放入该listener的claimedTouches
listener->_claimedTouches.push_back(*touchesIter);
}
}
}
//假设是后三个move end cancel
else if (listener->_claimedTouches.size() > 0
&& ((removedIter = std::find(listener->_claimedTouches.begin(), listener->_claimedTouches.end(), *touchesIter)) != listener->_claimedTouches.end()))
{
isClaimed = true;
//调用对应的callBack
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;
case EventTouch::EventCode::CANCELLED:
if (listener->onTouchCancelled)
{
listener->onTouchCancelled(*touchesIter, event);
}
if (listener->_isRegistered)
{
listener->_claimedTouches.erase(removedIter);
}
break;
default:
CCASSERT(false, "The eventcode is invalid.");
break;
}
}
// If the event was stopped, return directly.
if (event->isStopped())
{
updateListeners(event);
return true;
}
CCASSERT((*touchesIter)->getID() == (*mutableTouchesIter)->getID(), "");
//假设接收该touch而且须要吞噬该touch。会有两个影响
//1.Touches（standard 触摸机制）的触摸操作都接收不到该touch了
//2.由于返回值是true，在调用dispatchEventToListeners时。在该node之后的node将会不再接收该touch
if (isClaimed && listener->_isRegistered && listener->_needSwallow)
{
if (isNeedsMutableSet)
{
mutableTouchesIter = mutableTouches.erase(mutableTouchesIter);
isSwallowed = true;
}
return true;
}
return false;
};
//结合上面的dispatchEventToListeners的源代码分析。能够看出新版本号的OneByOne touch机制是这种：
//1.listener依据Node的优先级排序后。依次响应。值得注意的是，新版本号的优先级是依据Node的global Zorder来的。而不是2.x的触摸优先级。
//2.当TouchEvent Began来了之后，全部的listener会依次影响Touch Began。
然后再依次响应Touch Move...而不是一个listener响应完
//began move end之后 轮到下一个listener响应的顺序。
//3.吞噬操作仅仅有发生在began return true后才干够发生
dispatchEventToListeners(oneByOneListeners, onTouchEvent);
if (event->isStopped())
{
return;
}
if (!isSwallowed)
++mutableTouchesIter;
}
}
//
// process standard handlers 2nd
//
//相比于OneByOne。AllAtOnce要简单很多。值得注意的是被吞噬的touch也不会被AllAtOnce响应到
if (allAtOnceListeners && mutableTouches.size() > 0)
{
auto onTouchesEvent = [&](EventListener* l) -> bool{
EventListenerTouchAllAtOnce* listener = static_cast<EventListenerTouchAllAtOnce*>(l);
// Skip if the listener was removed.
if (!listener->_isRegistered)
return false;
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 eventcode is invalid.");
break;
}
// If the event was stopped, return directly.
if (event->isStopped())
{
updateListeners(event);
return true;
}
return false;
};
dispatchEventToListeners(allAtOnceListeners, onTouchesEvent);
if (event->isStopped())
{
return;
}
}
updateListeners(event);
}
2.当TouchEvent Began来了之后，全部的listener会依次影响Touch Began。然后再依次响应Touch Move...而不是一个listener响应完 began move end之后 轮到下一个listener响应的顺序。
3.吞噬操作仅仅有发生在began return true后才干够发生
3.4.4 DispatchCustomEvent （新版本号的NotificationCenter机制）
void EventDispatcher::dispatchCustomEvent(const std::string &eventName, void *optionalUserData)
{
EventCustom ev(eventName);
ev.setUserData(optionalUserData);
dispatchEvent(&ev);
}