###写在开头的话 本人工作是有5，6年了，但是C++也荒废了5.6年，这次重新拿起来忘记了好多东西.有什么地方说的不对的地方请各位高手指点一下.本人非常感谢. ###CCApplication的来源
CCApplication继承自CCApplicationProtocol,这个我们先不管它,我们自己写个例子
1.新建CCApplication类
/* * CCApplication.h * * Created on: 2013-9-21 * Author: sjbwybls */
#ifndef CCAPPLICATION_H_
#define CCAPPLICATION_H_
#include <iostream>
#include <string>
namespace TestCocos2dx {
using namespace std;
class CCApplication { public: CCApplication(); virtual ~CCApplication(); int run(); static CCApplication * sharedApplication() { cout<<"return static app"<<endl; return sm_pSharedApplication; }
protected: static CCApplication * sm_pSharedApplication;
};
} /* namespace TestCocos2dx */
#endif /* CCAPPLICATION_H_ */
/* * CCApplication.cpp * * Created on: 2013-9-21 * Author: sjbwybls */
#include "CCApplication.h"
namespace TestCocos2dx {
CCApplication *CCApplication::sm_pSharedApplication = 0;
CCApplication::CCApplication() { cout << "app ctor" << endl; sm_pSharedApplication = this; }
CCApplication::~CCApplication() { cout << "app destroy" << endl; sm_pSharedApplication = NULL; }
int CCApplication::run(){ cout << "run() function, sm_pSharedApplication = " << sm_pSharedApplication << endl; return 0;
}
} /* namespace TestCocos2dx */
- 新建CCDerivedCCApplication类继承自CCApplication
/* * CCDerivedCCApplication.h * * Created on: 2013-9-21 *
Author: sjbwybls */#ifndef CCDERIVEDCCAPPLICATION_H_
#define CCDERIVEDCCAPPLICATION_H_
#include <iostream>
#include <string>
#include "CCApplication.h"
namespace TestCocos2dx {
class CCDerivedCCApplication: public TestCocos2dx::CCApplication { public: CCDerivedCCApplication(); virtual ~CCDerivedCCApplication(); };
} /* namespace TestCocos2dx / #endif / CCDERIVEDCCAPPLICATION_H_ */
/* * CCDerivedCCApplication.cpp * * Created on: 2013-9-21 *
Author: sjbwybls */#include "CCDerivedCCApplication.h"
namespace TestCocos2dx {
using namespace std;
CCDerivedCCApplication::CCDerivedCCApplication() { cout<<"DerivedCCApplication ctor"<<endl;
}
CCDerivedCCApplication::~CCDerivedCCApplication() { cout<<"DerivedCCApplication destory"<<endl; }
} /* namespace TestCocos2dx */
3.最后建立main.cpp
/* * main.cpp * * Created on: 2013-9-21 * Author: sjbwybls */
#include "CCApplication.h"
#include "CCDerivedCCApplication.h"
using namespace TestCocos2dx;
int main() { CCApplication::sharedApplication()->run(); CCDerivedCCApplication app; CCApplication::sharedApplication()->run(); }
4.输出结果 return static app run() function, sm_pSharedApplication = 0 app ctor DerivedCCApplication ctor return static app run() function, sm_pSharedApplication = 0x7fff56b50c20 DerivedCCApplication destory app destroy
5.分析 main.cpp中的实例化了一个CCDerivedCCApplication的实例app。 调用流程： 返回静态父类实体并执行run函数
父类构造函数 子类构造函数 执行run函数 析构子类函数 析构父类函数
6.结论 先从C++的语法说明: C++中静态函数不会触发构造函数 声明一个对象不需要new.即可触发构造函数([具体可参考][1]) 父类跟子类的 构造函数调用关系为 先初始化父类构造函数再初始化子类构造函数 析构函数为 刚好相反 先调用子类析构函数再调用父类析构函数 CCApplication的用法 CCApplication app; //先调用Application必须先初始化Application,也可以从子类调用 CCApplication::sharedApplication()->run(); //最后执行run方法才能拿到初始化之后的Application，负责就只会等到空指针错误，这个也就是Fatal signal 11 (SIGSEGV) at 0x00000000 (code=1)错误出现的原因吧，希望高手拍砖
本文启发自:[初学试试看cocos2dx的TestCPP框架(1)][2] [1]:http://www.metsky.com/archives/580.html "声明类实例用new与不用new的区别" [2]:http://blog.csdn.net/hayyoung/article/details/8536719 "初学试试看cocos2dx的TestCPP框架(1)"
来源：oschina
链接：https://my.oschina.net/u/130461/blog/162838