cocos2dx-3.0 ： EventListener

#ifndef cocos2d_libs_EventListener_h
#define cocos2d_libs_EventListener_h

#include "CCPlatformMacros.h"
#include "CCObject.h"

#include <functional>
#include <string>
#include <memory>
#include <set>

NS_CC_BEGIN

class Event;
class Node;

/**
*  The base class of event listener.
*  If you need custom listener which with different callback, you need to inherit this class.
*  For instance, you could refer to EventListenerAcceleration, EventListenerKeyboard, EventListenerTouchOneByOne, EventListenerCustom.
*/
class EventListener : public Object
{
public:
enum class Type
{
UNKNOWN,
TOUCH_ONE_BY_ONE,
TOUCH_ALL_AT_ONCE,
KEYBOARD,
MOUSE,
ACCELERATION,
CUSTOM
};

typedef std::size_t ListenerID;

protected:
/** Constructor */
EventListener();

/** Initializes event with type and callback function */
bool init(Type t, ListenerID listenerID, std::function<void(Event*)>callback);
public:
/** Destructor */
virtual ~EventListener();

/** 检查该监听是否有效 */
virtual bool checkAvailable() = 0;

/** Clones the listener, its subclasses have to override this method. */
virtual EventListener* clone() = 0;

protected:
inline void setPaused(bool paused) { _paused = paused; };
inline bool isPaused() const { return _paused; };

inline void setRegistered(bool registered) { _isRegistered = registered; };
inline bool isRegistered() const { return _isRegistered; };

inline Type getType() const { return _type; };
inline ListenerID getListenerID() const { return _listenerID; };

inline void setFixedPriority(int fixedPriority) { _fixedPriority = fixedPriority; };
inline int getFixedPriority() const { return _fixedPriority; };

inline void setSceneGraphPriority(Node* node) { _node = node; };
inline Node* getSceneGraphPriority() const { return _node; };

std::function<void(Event*)> _onEvent;   /// 事件响应函数； c++11

Type _type;                             /// 事件类型，区分重力事件，键盘事件，touch 事件等
ListenerID _listenerID;                         /// Event listener ID
bool _isRegistered;                     /// 该监听是否被注册到dispather中

// The priority of event listener
int   _fixedPriority;   // 数值越大，优先级越高。0则表示基于场景图优先级

Node* _node;            // 场景图优先级
bool _paused;           // 该监听是否暂停

friend class EventDispatcher;
};

NS_CC_END

#endif