[cocos2dx 3.x]Label类数字变化动作

之前写了个2.14版本的动作变化，见 http://www.cnblogs.com/creeper/p/3531304.html

3.x版本变化了很多，但是核心思想还是没有变化，所以对应3.x版本的改了一下放上来

有空的话把tolua的转换方法也放上来吧:)

 #ifndef __MISC_NODE_CCNUMBER_CHANGE_H__
 #define __MISC_NODE_CCNUMBER_CHANGE_H__
 
 #include <vector>
 
 #include "2d/CCAction.h"
 #include "2d/CCAnimation.h"
 #include "2d/CCActionInterval.h"
 #include "base/CCProtocols.h"
 #include "base/CCVector.h"
 
 //NS_CC_BEGIN
 USING_NS_CC;
 class Node;
 class SpriteFrame;
 class EventCustom;
 
 class NumberChange : public ActionInterval
 {
 public:
 
     static NumberChange* create(float duration, int fromNum, int toNum);
 
     virtual NumberChange* clone() const override;
     virtual NumberChange* reverse(void) const  override;
     virtual void startWithTarget(cocos2d::Node *target) override;
     virtual void update(float time) override;
 
 CC_CONSTRUCTOR_ACCESS:
     NumberChange();
     virtual ~NumberChange();
 
     /** initializes the action */
     bool initWithDuration(float duration, int fromNum, int toNum);
 
 protected:
     int _fromNum;
     int _toNum;
 
 private:
     CC_DISALLOW_COPY_AND_ASSIGN(NumberChange);
 };
 
 //NS_CC_END
 
 #endif //__MISC_NODE_CCNUMBER_CHANGE_H__

 #include "2d/CCActionInterval.h"
 
 #include <stdarg.h>
 
 #include "2d/CCSprite.h"
 #include "2d/CCNode.h"
 #include "2d/CCSpriteFrame.h"
 #include "2d/CCActionInstant.h"
 #include "base/CCDirector.h"
 #include "base/CCEventCustom.h"
 #include "base/CCEventDispatcher.h"
 #include "platform/CCStdC.h"
 #include "deprecated/CCString.h"
 #include "NumberChange.h"
 
 USING_NS_CC;
 //NS_CC_BEGIN
 NumberChange::NumberChange(){
 }
 
 NumberChange::~NumberChange(){
 }
 
 NumberChange* NumberChange::create(float duration, int fromNum, int toNum)
 {
     NumberChange *ret = new (std::nothrow) NumberChange();
     ret->initWithDuration(duration, fromNum, toNum);
     ret->autorelease();
 
     return ret;
 }
 
 bool NumberChange::initWithDuration(float duration, int fromNum, int toNum)
 {
     if (ActionInterval::initWithDuration(duration))
     {
         _fromNum = fromNum;
         _toNum = toNum;
         return true;
     }
 
     return false;
 }
 
 NumberChange* NumberChange::clone() const
 {
     // no copy constructor
     auto a = new (std::nothrow) NumberChange();
     a->initWithDuration(_duration, _fromNum, _toNum);
     a->autorelease();
     return a;
 }
 
 void NumberChange::startWithTarget(cocos2d::Node *target)
 {
     ActionInterval::startWithTarget(target);
     LabelProtocol *pLabel = dynamic_cast<LabelProtocol*>(target);
     if (pLabel)
     {
         std::string numStr = cocos2d::StringUtils::format("%i", _fromNum);
         pLabel->setString(numStr.c_str());
     }
 }
 
 NumberChange* NumberChange::reverse() const
 {
     return NumberChange::create(_duration, _toNum, _fromNum);
 }
 
 void NumberChange::update(float t)
 {
     LabelProtocol *pLabel = dynamic_cast<LabelProtocol*>(_target);
     if (pLabel)
     {
         int tempNum = (_toNum - _fromNum) * t;
         int num = _fromNum + tempNum;
         std::string numStr = cocos2d::StringUtils::format("%i", num);
         pLabel->setString(numStr.c_str());
     }
 }
 
 //NS_CC_END