学习Cocos2dx引擎之CCApplication
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
#include
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
#include
#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)
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)