Cocos2d-x 创建（create）动画对象CCAnimation报错分析

本人在使用精灵表单创建动画的过程中突然遇到了一些个问题，下面进行一下分析总结。

根据在Cocos2d-iphone中的经验，我写出了如下的代码：

CCSpriteFrameCache::sharedSpriteFrameCache()->addSpriteFramesWithFile("my.plist");
    CCSpriteBatchNode *batchNode = CCSpriteBatchNode::create("my.png");
    this->addChild(batchNode);

    CCArray *frameArray = CCArray::create();

    for (int i=1; i<=4; i++) {
        CCSpriteFrame *frame = CCSpriteFrameCache::sharedSpriteFrameCache()->spriteFrameByName(CCString::createWithFormat("switch_off_1_%d.png",i)->getCString());
        frameArray->addObject(frame);
    }

    CCAnimation *animation = CCAnimation::create(frameArray, 0.4);

    CCAnimate *animate = CCAnimate::create(animation);

    CCSprite *iconSprite = CCSprite::createWithSpriteFrame(CCSpriteFrameCache::sharedSpriteFrameCache()->spriteFrameByName("switch_off_1_4.png"));

    iconSprite->setPosition(ccp(100,100));

    this->addChild(iconSprite);

    iconSprite->runAction(CCRepeatForever::create(animate));

但是程序出错：

Cocos2d: Assert failed: element type is wrong!
Assertion failed: (dynamic_cast<CCAnimationFrame*>(*__arr__)), function initWithAnimationFrames, file /Users/ios/Desktop/demo/demo/libs/cocos2dx/sprite_nodes/CCAnimation.cpp, line 144.

原来是

CCAnimation *animation = CCAnimation::create(frameArray, 0.4); 出了问题！

直接用create方法，会进入initWithAnimationFrames方法，里面会检查传入的CCArray是否是CCAnimationFrame*类型，而显然，我代码中CCArray中的元素是CCSpriteFrame*，所以出现了问题。

那么解决方法是：改用

CCAnimation *animation =CCAnimation::createWithSpriteFrames(frameArray,0.4); 这个方法就可以了。

注意：在xcode中代码提示 createWithSpriteFrames 这个方法只有一个参数，

但是，实际上进入这个函数就回发现，它是有两个参数的。

/* Creates an animation with an array of CCSpriteFrame and a delay between frames in seconds.
     The frames will be added with one "delay unit".
     @since v0.99.5
    */
    static CCAnimation* createWithSpriteFrames(CCArray* arrayOfSpriteFrameNames, float delay = 0.0f);

注意其中的注释：
Creates an animation with an array of CCSpriteFrame and a delay between frames in seconds

对比create方法中的注释：

Creates an animation with an array of CCAnimationFrame, the delay per units in seconds and and how many times it should be executed.

 /* Creates an animation with an array of CCAnimationFrame, the delay per units in seconds and and how many times it should be executed.
     @since v2.0
     */
    static CCAnimation* create(CCArray *arrayOfAnimationFrameNames, float delayPerUnit, unsigned int loops);
    static CCAnimation* create(CCArray *arrayOfAnimationFrameNames, float delayPerUnit) {
        return CCAnimation::create(arrayOfAnimationFrameNames, delayPerUnit, 1);
    }

这样就知道出错的原因了吧！

下面给出另一种方法创建动画的方式：

CCSpriteFrameCache::sharedSpriteFrameCache()->addSpriteFramesWithFile("my.plist");
    CCSpriteBatchNode *batchNode = CCSpriteBatchNode::create("my.png");
    this->addChild(batchNode);

    CCAnimation *animation = CCAnimation::create();

    for (int i=1; i<=4; i++) {
        CCSpriteFrame *frame = CCSpriteFrameCache::sharedSpriteFrameCache()->spriteFrameByName(CCString::createWithFormat("switch_off_1_%d.png",i)->getCString());
        animation->addSpriteFrame(frame);
    }

    animation->setDelayPerUnit(0.4);

    CCAnimate *animate = CCAnimate::create(animation);

    CCSprite *iconSprite = CCSprite::createWithSpriteFrame(CCSpriteFrameCache::sharedSpriteFrameCache()->spriteFrameByName("switch_off_1_4.png"));

       //    CCSize size = CCDirector::sharedDirector()->getWinSize();
    iconSprite->setPosition(ccp(100,100));

    this->addChild(iconSprite);

    iconSprite->runAction(CCRepeatForever::create(animate));

参考文章：http://blog.csdn.net/rabbitlbj/article/details/8765575