cocos2d-x 游戏开发之有限状态机(FSM) (三)

有限状态机简称FSM，现在我们创建一个专门的FSM类，负责管理对象(Monkey)的状态。然后Monkey类就实现了行为与状态分离。Monkey类只负责自己的行为，MonkeyFSM作为Monkey的成员，负责状态调度。MonkeyFSM调用状态模式类的方法，状态模式类调用真实对象Monkey的方法。注意本文例子代码只是为了说明问题，并不能真正用于实际当中。其中Monkey与MonkeyFSM互相保存对方的指针，存在循环引用问题。

代码部分：

MonkeyFSM：

// MonkeyFSM.h//#ifndef MONKEY_FSM_H_#define MONKEY_FSM_H_#include "cocos2d.h"USING_NS_CC;#include "State.h"class Monkey;class MonkeyFSM    : public Node{public:    MonkeyFSM()    {        _monkey = 0;        _state = 0;        log("MonkeyFSM()");    }    static MonkeyFSM * createObject(Monkey * mk)    {        MonkeyFSM * fsm = new MonkeyFSM();        fsm->initWithMonkey(mk);        return fsm;    }    bool initWithMonkey(Monkey * mk)    {        _monkey = mk;        return true;    }    void changeState(State * newState)    {        State * oldState = _state;        _state = newState;        if (oldState) {            delete oldState;        }    }    virtual void update(float dt)    {        if (_state) {            _state->execute(_monkey);        }    }private:    State * _state;    Monkey * _monkey;};#endif // MONKEY_FSM_H_

Monkey：

#ifndef MONKEY_H_#define MONKEY_H_#include <time.h>#include "cocos2d.h"USING_NS_CC;#include "MonkeyFSM.h"#define MAX_STOP_TIME  10#define MAX_WALK_TIME  20#define MAX_WALK_DIST  100class Monkey    : public Node{public:    Monkey()    {        log("Monkey()");    }    CREATE_FUNC(Monkey);     virtual bool init()    {        _curPos = 0;        _step = 1;        _fsm = MonkeyFSM::createObject(this);        this->scheduleUpdate();        return true;    }    void stop()    {        cocos2d::log("stop()");    }    void walk()    {        _curPos += _step;        cocos2d::log("walk(): pos=%d", _curPos);    }    void turn()    {        _step *= -1;        cocos2d::log("turn(): step=%d", _step);            }    MonkeyFSM * getFSM()    {        return _fsm;    }    void update(float dt)    {        if (_fsm) {            _fsm->update(dt);        }    }private:    MonkeyFSM * _fsm;    time_t _curTime;    int      _curPos;    int      _step;public:    bool isStopTimeout()    {        return (time(0) - _curTime > MAX_STOP_TIME);    }    bool isWalkTimeout()    {        return (time(0) - _curTime > MAX_WALK_TIME);    }    bool isWalkOutBorder()    {        return (_curPos > MAX_WALK_DIST || _curPos < -MAX_WALK_DIST);    }};#endif // MONKEY_H_

状态模式类，.h文件没有变化：

// State.h//#ifndef STATE_H_#define STATE_H_class Monkey;struct State{   virtual void execute(Monkey *mk) = 0;};#endif // STATE_H_

// WalkState.h//#ifndef WALK_STATE_H_#define WALK_STATE_H_#include "State.h"#include "Monkey.h"class WalkState    : public State{public:    virtual void execute(Monkey *mk);};#endif // WALK_STATE_H_

// WalkState.cpp//#include "WalkState.h"#include "TurnState.h"#include "StopState.h"void WalkState::execute(Monkey *mk){    mk->walk();    if (mk->isWalkOutBorder()) {        mk->getFSM()->changeState(new TurnState());        mk->turn();    } else if (mk->isWalkTimeout()) {        mk->getFSM()->changeState(new StopState());        mk->stop();    }}