cocos2dx 3.1 CC_CALLBACK用std::bind替换CC_CALLBACK_N
在cocos2dx 3.0 版本中，回调函数基本上由4个CC_CALLBACK_N 函数代替，N代表回调函数的参数个数
1.先让我们来看看这些CC_CALLBACK_N怎么用
比如action的回调 ,CC_CALLBACK_0
auto animation = Animation::create();
auto animate = Animate::create(animation);
CallFunc* animateDone = CallFunc::create(CC_CALLBACK_0(PlaneLayer::removePlane,this));
auto sequence = Sequence::create(animate,animateDone,NULL);
sprite1->runAction(sequence);
void PlaneLayer::removePlane(){
//.....
}
auto actionMove = MoveTo::create(randomDuration, Point(0, 0));
auto actionDone = CallFuncN::create(CC_CALLBACK_1(EnemyLayer::enemy1MoveFinished,this));
auto sequence = Sequence::create(actionMove,actionDone,NULL);
sprite2->runAction(sequence);
void EnemyLayer::enemy1MoveFinished(Node* pSender){
Sprite* sprite2 = (Sprite*)pSender;
}
auto pauseNormal = Sprite::create("game_pause_nor.png");
auto pausePressed = Sprite::create("game_pause_pressed.png");
auto menuItem = MenuItemSprite::create(pauseNormal,pausePressed,NULL,CC_CALLBACK_1(ControlLayer::menuPauseCallback,this));
menuItem->setPosition(Point::ZERO);
auto menuPause = Menu::create(menuItem,NULL);
menuPause->setPosition(Point::ZERO);
//回调函数
void ControlLayer::menuPauseCallback(Object* pSender)
{
//....
}
//单点触摸
virtual bool onTouchBegan(Touch *touch, Event *unused_event);
virtual void onTouchMoved(Touch *touch, Event *unused_event);
virtual void onTouchEnded(Touch *touch, Event *unused_event);
virtual void onTouchCancelled(Touch *touch, Event *unused_event);
auto dispatcher = Director::getInstance()->getEventDispatcher();
auto listener = EventListenerTouchOneByOne::create();
listener->onTouchBegan = CC_CALLBACK_2(GameLayer::onTouchBegan,this);
listener->onTouchMoved = CC_CALLBACK_2(GameLayer::onTouchMoved,this);
listener->onTouchEnded = CC_CALLBACK_2(GameLayer::onTouchEnded,this);
listener->setSwallowTouches(true);//不向下传递触摸
dispatcher->addEventListenerWithSceneGraphPriority(listener,this);
一般来说：
CallFunc用于 不带参数的，
CallFuncN 用于创建 带一个Node节点参数的，Node*节点参数是动作的执行者
CCCallFuncND 比CallFuncN多了一个参数，可以是任意类型的参数 void *,用法看下面
auto animation = AnimationCache::getInstance()->animationByName("Enemy1Blowup");
auto animate = Animate::create(animation);
CCCallFuncND* animateDone = CCCallFuncND::create(this,callfuncND_selector(EnemyLayer::removeEnemy1),(void*)enemy1);
auto sequence = Sequence::create(animate, animateDone,NULL);
Sprite* m_sprite = enemy1->getSprite();
m_sprite ->runAction(sequence);
void EnemyLayer::removeEnemy1(Node* pTarget, void* data){
Sprite* m_sprite = (Sprite*) pTarget; //node节点为动作的执行者
Enemy* enemy1 = (Enemy*)data; //我们传的自定义数据enemy1
//...
}
CCCallFuncND* animateDone = CCCallFuncND::create(this,callfuncND_selector(EnemyLayer::removeEnemy1),(void*)enemy1);
我们还可以这样子写：
//写法1 CCCallFuncN* animateDone = CCCallFuncN::create(CC_CALLBACK_1(EnemyLayer::removeEnemy1,this,enemy1)); //写法2 CCCallFunc* animateDone = CCCallFunc::create(CC_CALLBACK_0(EnemyLayer::removeEnemy1,this,enemy1->getSprite(),enemy1)); //写法3，用std::bind CCCallFuncN* animateDone = CCCallFuncN::create(std::bind(&EnemyLayer::removeEnemy1,this,enemy1->getSprite(),enemy1));
恩，是不是有点乱，记不住没关系，我也经常没记住，我们来具体看一下CC_CALLBACK_N到底是神马玩意
// 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__)
是不是看到了std::bind、##__VA_ARGS__、std::placeholders::_1等等，这些都是神马玩意，
先解释一下：
std::placeholders::_1是参数占位符，表示第一个参数，以此类推
那std::bind是神马，不急我们先看一段代码
#include <iostream>
#include <functional>
using namespace std;
typedef std::function<void ()> fp;
void g_fun()
{
cout<<"g_fun()"<<endl;
}
class A
{
public:
static void A_fun_static()
{
cout<<"A_fun_static()"<<endl;
}
void A_fun()
{
cout<<"A_fun()"<<endl;
}
void A_fun_int(int i)
{
cout<<"A_fun_int() "<<i<<endl;
}
void A_fun_int_double(int i,int p)
{
cout<<"A_fun_int_double ()"<<i<<","<<p<<endl;
}
//非静态类成员，因为含有this指针，所以需要使用bind
void init()
{
//绑定不带参数的函数
fp fp1=std::bind(&A::A_fun,this);
fp1();
}
void init2()
{
typedef std::function<void (int)> fpi;
//绑定带一个参数的函数
fpi f=std::bind(&A::A_fun_int,this,std::placeholders::_1);//参数要使用占位符 std::placeholders::_1表示第一个参数
f(5);
}
void init3(){
typedef std::function<void (int,double)> fpid;
//绑定带两个参数的函数
fpid f=std::bind(&A::A_fun_int_double,this,std::placeholders::_1,std::placeholders::_2);
f(5,10);
}
};
int main()
{
//绑定到全局函数
fp f2=fp(&g_fun);
f2();
//绑定到类静态成员函数
fp f1=fp(&A::A_fun_static);
f1();
A().init();
A().init2();
A().init3();
return 0;
}
g_fun() A_fun_static() A_fun() A_fun_int() 5 A_fun_int_double ()5,10
std::function --> 绑定到全局函数/类静态成员函数(类静态成员函数与全局函数没有区别)
std::bind --> 绑定到类的非静态成员函数
到这里是不是有豁然开朗的感觉呢，哈哈,知道了bind函数怎么用，然后我们就可以使用std::bind替换CC_CALLBACK_N写法了
3.使用std：bind函数替换CC_CALLBACK_N：
比如我们要替换CC_CALLBACK_0
auto animation = Animation::create();
auto animate = Animate::create(animation);
//CallFunc* animateDone = CallFunc::create(CC_CALLBACK_0(PlaneLayer::removePlane,this));
CallFunc* animateDone = CallFunc::create(std::bind(&PlaneLayer::removePlane,this));//替换
auto sequence = Sequence::create(animate,animateDone,NULL);
sprite1->runAction(sequence);
void PlaneLayer::removePlane(){
//.....
}
auto actionMove = MoveTo::create(randomDuration, Point(0, 0));
//auto actionDone = CallFuncN::create(CC_CALLBACK_1(EnemyLayer::enemy1MoveFinished,this));
auto actionDone = CallFuncN::create(std::bind(&EnemyLayer::enemy1MoveFinished,this,enemy1));//替换
auto sequence = Sequence::create(actionMove,actionDone,NULL);
sprite2->runAction(sequence);
void EnemyLayer::enemy1MoveFinished(Node* pSender){
Sprite* sprite2 = (Sprite*)pSender;
}
auto animation = AnimationCache::getInstance()->animationByName("Enemy1Blowup");
auto animate = Animate::create(animation);
//CCCallFuncND* animateDone = CCCallFuncND::create(this,callfuncND_selector(EnemyLayer::removeEnemy1),(void*)enemy1);
CCCallFuncN* animateDone = CCCallFuncN::create(std::bind(&EnemyLayer::removeEnemy1,this,enemy1->getSprite(),enemy1));//替换
auto sequence = Sequence::create(animate, animateDone,NULL);
Sprite* m_sprite = enemy1->getSprite();
m_sprite ->runAction(sequence);
void EnemyLayer::removeEnemy1(Node* pTarget, void* data){
Sprite* m_sprite = (Sprite*) pTarget; //node节点为动作的执行者
Enemy* enemy1 = (Enemy*)data; //我们传的自定义数据enemy1
//...
}