cocos2d-x 断言和函数回调
更新:HHH   时间:2023-1-7


1.什么是断言?

断言assert 是仅在Debug 版本起作用的宏,它用于检查“不应该”发生的情况。如果是Release版本,编译器忽略所有的断言(看成空语句)。

CC_ASSERT(条件)
#define CC_ASSERT(cond) assert(cond)


CCAsert(条件,"打印信息")
#if COCOS2D_DEBUG > 0
extern bool CC_DLL cc_assert_script_compatible(const char *msg);
#define CCAssert(cond, msg) do {                              \
      if (!(cond)) {                                          \
        if (!cc_assert_script_compatible(msg) && strlen(msg)) \
          cocos2d::CCLog("Assert failed: %s", msg);           \
        CC_ASSERT(cond);                                      \
      } \
    } while (0)
#else
#define CCAssert(cond, msg) ((void)(cond))
#endif


例子:

//addChild方法,如果要添加的子节点为空,就停住了,并打印信息“Argument must be non-nil”
void CCNode::addChild(CCNode *child)
{    //不为空不成立,就是为空啦
    CCAssert( child != NULL, "Argument must be non-nil");
    this->addChild(child, child->m_nZOrder, child->m_nTag);
}

2.函数回调,主要有三种方式(无参数,一个参数,二个参数)

void call1();
void call2(CCNode* node);
void call3(CCNode* node,void* data);

实现:

void HelloWorld::call1(){
                                               
    CCLog("call1");
                                               
}
void HelloWorld::call2(CCNode* node){
                                               
    CCLog("call2");
}
void HelloWorld::call3(CCNode* node,void* data){
                                               
    CCLog("call3");
                                               
    CCSprite* sp =(CCSprite*) data;
    sp->setScale(2.0f);
                                               
}

函数回调:


   CCSprite* sp = CCSprite::create("CloseNormal.png");
    sp->setPosition(CCPointZero);
    addChild(sp);
    CCJumpTo* jump = CCJumpTo::create(1, ccp(400,20), 60, 8);
// 无参
    CCCallFunc* fun1 = CCCallFunc::create(this, callfunc_selector(HelloWorld::call1));
//一个参数
    CCCallFunc* fun2 = CCCallFuncN::create(this, callfuncN_selector(HelloWorld::call2));
//两个参数
    CCCallFunc* fun3 = CCCallFuncND::create(this, callfuncND_selector(HelloWorld::call3),(void*)sp);
    CCSequence* seq = CCSequence::create(jump,fun1,fun2,fun3,0);
                              
    sp->runAction(seq);

3.CCProgressTo使用:

//TestCpp中的例子
            
    CCSprite* sp = CCSprite::create("CloseNormal.png");
    sp->setPosition(CCPointZero);
    addChild(sp);
            
    CCSize s = CCDirector::sharedDirector()->getWinSize();
    CCProgressTo *to1 = CCProgressTo::create(2, 100);
    CCProgressTimer *left = CCProgressTimer::create(sp);
    left->setType( kCCProgressTimerTypeRadial );
//圆形进度
    addChild(left);
    left->setPosition(ccp(100, s.height/2));
    left->runAction( CCRepeatForever::create(to1));

哈哈,一天一点进步,加油

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