cocos2d-x3.1 callback function specific explanation

cocos2d-x3.1 the definition of the callback function CCRef.h declaration. Source code, for example, the following:

typedef void (ref::* Sel_callfunc) (), typedef void (ref::* SEL_CALLFUNCN) (node*), typedef void (ref::* SEL_CALLFUNCND) ( node*, void*), typedef void (ref::* Sel_callfunco) (ref*), typedef void (ref::* Sel_menuhandler) (ref*); typedef void (ref:: *sel_schedule) (float), #define Callfunc_selector (_selector) static_cast<cocos2d::sel_callfunc> (&_ SELECTOR) #define Callfuncn_selector (_selector) static_cast<cocos2d::sel_callfuncn> (&_selector) #define Callfuncnd_selector (_selector) static_cast<cocos2d::sel_callfuncnd> (&_selector) #define CallfuncO_ Selector (_selector) static_cast<cocos2d::sel_callfunco> (&_selector) #define Menu_selector (_SELECTOR) Static_cast<cocos2d::sel_menuhandler> (&_selector) #define Schedule_selector (_selector) static_cast< Cocos2d::sel_schedule> (&_selector)

As a matter of fact. This is the application of the function pointer.

The following uses a simple sample to illustrate the use of function pointers:

typedef void (*P) (int i); void func (int i) {    printf ("%d\n", I);} p = func;  P (1);

A new type is defined by typedef p,p is a function pointer with an int value for the function's parameters. The return void,p pointer can point to this function. The function name is a pointer, so p is directly equal to Func, then P (1), run

Through this example can be found. This is also true of Cocos2d-x's callback function. 6 function pointer types are defined first. Can only point to a member function of a ref class. Then define a definition of the macro that calls these function pointers. These macro definitions are called back by the callback object's Cc_callback_, and here is a sample.

#include <iostream>  //callback.husing namespace std;//defines a base class Person{public:    void Print (string name);//define the base class method};//typedef a function pointer type typedef void (person::* sel_callfun) (string str);//define a derived class class Student:public Person{private:    string m_name;    int m_age;public:    Student (string name, int age);    ~student ();        void CallBack (String str);//define a callback function    void result ();//print result protected:    person* m_plisten;//callback function Run Object    sel_ Callfun m_pfnselectior;//callback function pointer};

#include "CallBack.h"  //callback.cpp//defines a base class void Person::p rint (string name) {    cout << name << Endl ;} Student::student (string name, int age) {    this->m_name = name;    This->m_age = age;} Student::~student () {    }void Student::result () {    cout << "Hi This is a Student" << Endl;        M_pfnselectior = (sel_callfun) (&student::callback);//First turn the callback function of the subclass into a function pointer        m_plisten = this;//The Run object is this        m_ Plisten->print (m_name);//First run the print function (M_plisten->*m_pfnselectior) of the parent class (        m_name);//Run the callback function, that is, the callback function of the subclass }void student::callback (String str) {    cout << ' My name is ' << str << ' age is ' << m_age << ; Endl;}

#include <iostream>//main.cpp#include "CallBack.h" int main (int argc, const char * argv[]) {    //Insert code here ...    student* s = new Student ("yxk", +);    S->result ();    return 0;}

The subclass of the callback function by demonstrating a sample person object

cocos2d-x3.1 callback function specific explanation