标签：cocos2d-x
对于cocos2d-x经常要用到的方法，不得不好好研究一下，这次的研究真心有收获。为了动作能够回调我们的函数，我们必须先声明并实现他们。
void callBack();
void callBack_1(Node* node);
void callBack_2(Node* node,const char* str);
void Nice::callBack()
{
log("Nice::callBack()");
}
void Nice::callBack_1(Node* node)
{
log("This tag is %d",node->getTag());
}
void Nice::callBack_2(Node* node,const char* str)
{
log("This tag is %d, and str is %s",node->getTag(), str);
}
//然后就开始创建我们伟大的精灵了。
sp_area = Sprite::create("newAlwaysShow.png");//sp_area is a class member ,Sprite* ap_area;
sp_area->setTag(1314);
auto sp_another = Sprite::create();
sp_another->setTag(520);
addChild(sp_another);
addChild(sp_area);
//翻滚吧，可爱的精灵们！
/*
CallFunc 创建的函数必须是无参数的
CallFuncN 创建的函数可以是一个至多个参数
*/
sp_area->runAction(Sequence::create(MoveTo::create(2, Vec2(200, 200)),
CallFunc::create(CC_CALLBACK_0(Nice::callBack, this)),
CallFuncN::create(CC_CALLBACK_1(Nice::callBack_2, this, "I have tow parameter")),
NULL));
//这样写完之后，发现runAction里面的东西好平淡（平淡有时候才不是真呢！），于是我就瞎写一通，残忍的把它变成了这个样子。
sp_area->runAction(Sequence::create(MoveTo::create(2, Vec2(200, 200)),
CallFunc::create(CC_CALLBACK_0(Nice::callBack, this)),
CallFunc::create([&]()->void{log("Done1");log("This tag is %d", sp_area->getTag());}),
CallFunc::create(std::bind(&Nice::callBack, this)),
CallFuncN::create(CC_CALLBACK_1(Nice::callBack_1, this)),//1314
CallFuncN::create(CC_CALLBACK_0(Nice::callBack_1, this, sp_another)),//520
CallFuncN::create([](Node* node){log("this tag is %d", node->getTag());}),//1314
CallFuncN::create(std::bind(&Nice::callBack_1, this, sp_area)),//1314
CallFuncN::create(std::bind(&Nice::callBack_1, this, sp_another)),//520
CallFuncN::create(CC_CALLBACK_1(Nice::callBack_2, this, "I have tow parameter")),
NULL));好吧，他现在已经面目全非了。其实这么多行也只是用到了两种方法而已，第一种lambda表达式，第二种std::bind()。（尼玛，你在逗我吗？不是还有CC_CALLBACK_0吗？）
额。既然这样就让我们来看下源码吧！
// new callbacks based on C++11 #define CC_CALLBACK_0(__selector__,__target__, ...) std::bind(&__selector__,__target__, ##__VA_ARGS__) #define CC_CALLBACK_1(__selector__,__target__, ...) std::bind(&__selector__,__target__, std::placeholders::_1, ##__VA_ARGS__) #define CC_CALLBACK_2(__selector__,__target__, ...) std::bind(&__selector__,__target__, std::placeholders::_1, std::placeholders::_2, ##__VA_ARGS__) #define CC_CALLBACK_3(__selector__,__target__, ...) std::bind(&__selector__,__target__, std::placeholders::_1, std::placeholders::_2, std::placeholders::_3, ##__VA_ARGS__)
Sequece::create是分平台实现的（分为win和其他）
#if (CC_TARGET_PLATFORM == CC_PLATFORM_WP8) || (CC_TARGET_PLATFORM == CC_PLATFORM_WINRT)
// WP8 in VS2012 does not support nullptr in variable args lists and variadic templates are also not supported
typedef FiniteTimeAction* M;
static Sequence* create(M m1, std::nullptr_t listEnd) { return variadicCreate(m1, NULL); }
static Sequence* create(M m1, M m2, std::nullptr_t listEnd) { return variadicCreate(m1, m2, NULL); }
static Sequence* create(M m1, M m2, M m3, std::nullptr_t listEnd) { return variadicCreate(m1, m2, m3, NULL); }
static Sequence* create(M m1, M m2, M m3, M m4, std::nullptr_t listEnd) { return variadicCreate(m1, m2, m3, m4, NULL); }
static Sequence* create(M m1, M m2, M m3, M m4, M m5, std::nullptr_t listEnd) { return variadicCreate(m1, m2, m3, m4, m5, NULL); }
static Sequence* create(M m1, M m2, M m3, M m4, M m5, M m6, std::nullptr_t listEnd) { return variadicCreate(m1, m2, m3, m4, m5, m6, NULL); }
static Sequence* create(M m1, M m2, M m3, M m4, M m5, M m6, M m7, std::nullptr_t listEnd) { return variadicCreate(m1, m2, m3, m4, m5, m6, m7, NULL); }
static Sequence* create(M m1, M m2, M m3, M m4, M m5, M m6, M m7, M m8, std::nullptr_t listEnd) { return variadicCreate(m1, m2, m3, m4, m5, m6, m7, m8, NULL); }
static Sequence* create(M m1, M m2, M m3, M m4, M m5, M m6, M m7, M m8, M m9, std::nullptr_t listEnd) { return variadicCreate(m1, m2, m3, m4, m5, m6, m7, m8, m9, NULL); }
static Sequence* create(M m1, M m2, M m3, M m4, M m5, M m6, M m7, M m8, M m9, M m10, std::nullptr_t listEnd) { return variadicCreate(m1, m2, m3, m4, m5, m6, m7, m8, m9, m10, NULL); }
// On WP8 for variable argument lists longer than 10 items, use the other create functions or variadicCreate with NULL as the last argument
static Sequence* variadicCreate(FiniteTimeAction* item, ...);
#else
static Sequence* create(FiniteTimeAction *action1, ...) CC_REQUIRES_NULL_TERMINATION;
#endif
Sequence* Sequence::create(FiniteTimeAction *action1, ...)
{
va_list params;
va_start(params, action1);
Sequence *ret = Sequence::createWithVariableList(action1, params);//传给了createWithVariableList让他来处理
va_end(params);
return ret;
}
Sequence* Sequence::createWithVariableList(FiniteTimeAction *action1, va_list args)
{
FiniteTimeAction *now;
FiniteTimeAction *prev = action1;
bool bOneAction = true;
while (action1)
{
now = va_arg(args, FiniteTimeAction*);
//如果第二个动作存在
if (now)
{
prev = createWithTwoActions(prev, now);
bOneAction = false;
}
//如果第二个动作不存在
else
{
// If only one action is added to Sequence, make up a Sequence by adding a simplest finite time action.
if (bOneAction)
{
prev = createWithTwoActions(prev, ExtraAction::create());
}
break;
}
}
return ((Sequence*)prev);
}
void manyArgument(int num, ...);
void Nice::manyArgument(int num, ...)
{
va_list params;
//va_start函数的第二个参数要和manyArgument的第一个参数一样
va_start(params, num);
int now;
log("fist is %d", num);
while (true)
{
now = va_arg(params, int);
if (now != -1)
{
log("now is %d", now);
}
else
{
break;
}
}
va_end(params);
}
manyArgument(1, 2, 3, 4, -1);
void manyArgument(int* num, ...);
void Nice::manyArgument(int* num, ...)
{
va_list params;
//va_start函数的第二个参数要和manyArgument的第一个参数一样
va_start(params, num);
int* now;
log("fist is %d", *num);
while (true)
{
now = va_arg(params, int*);
if (now != nullptr)
{
log("now is %d", *now);
}
else
{
break;
}
}
va_end(params);
}
int arr[] {3,6,9,12};
manyArgument(arr, arr+1, arr+2, arr+3, nullptr); #define MANYARGUMENT(__num__, ...) manyArgument(__num__, ##__VA_ARGS__)
MANYARGUMENT(arr, arr+1, arr+2, nullptr);
auto add_num = std::bind(&Nice::add, this, std::placeholders::_1, std::placeholders::_2, 10);
log("sum is %d", add_num(1, 1));//12
log("sum is %d", add_num(1, 1, 2));//12
log("sum is %d", add_num(1, 1, 2, 4));//12
//无论怎么改变参数的第三位也是固定死了是10的，神奇的是居然能传入四个参数，明摆着就是只认定前两个参数是有效的，后面的统统无效。
学到这里。貌似对这个流程还是比较清楚的嘛。虽然可能还有更多的只是没有发现，但是我们还有更多的时间没有用呀！
cocos2d-x 3.1.1 学习笔记［17］ 关于函数的那些勾当
标签：cocos2d-x
原文地址：http://blog.csdn.net/zhouyunxuan/article/details/38038017
