混合C ++和Objective-C [英] Mixing C++ and Objective-C

问题描述

我使用C ++作为应用程序的骨干和Objective-C的图形用户界面，这很好。

I am using C++ as the app backbone and Objective-C for the GUI, that's fine.

但是，当涉及到在Objective-C ++（.mm文件）混合在一起的code，我有几个问题：

But when it comes to mixing those code together in Objective-C++ (.mm file), I have got a few question:

例如。在Objective-C的头，我可以做到以下几点？

E.g. In Objective-C header, can I do the following?

#include <vector>
#include <boost\shared_ptr.hpp>
@interface MyClass : NSObject {
  std::vector<boost::shared_ptr<CCSprite> > m_spriteList;
}

然后在 .mm 文件，我想要做的。

CCSprite* newSprite = [/* cocos2d stuff here... */];
m_spriteList.push_back(newSprite);

是上面code有效吗？这当然是在C ++中，但混合C ++和Objective-C和Cocos2d的时候我不知道。

Is the above code valid? It certainly is in C++, but I am not sure when mixing C++ and Objective-C and Cocos2D.

当我尝试使用在Objective-C的C ++ code，我要声明一个C ++对象中的Objective-C头文件的成员变量。

When I try to use the C++ code in Objective-C, I want to declare a C++ object as a member variable in the Objective-C header file.

说我有在 test.h 头部声明C ++类：

Say I have a C++ class declared in the test.h header:

Test{
};

在Objective-C头文件，我想要做的。

In Objective-C header file, I want to do

#include "test.h"
#incude <boost/scoped_ptr.hpp>

#include <vector>
@interface MyClass : NSObject {
   Test* m_testObjectPtr; // (1)
   boost::scoped_ptr<Test>  m_testOjbSmartPtr; // (2)
}

在上面的code，为（2）行不行？我可以在C ++ code使用Objective-C的智能指针一样？而且我可以假设当 MyClass的对象被销毁的测试类析构函数将被调用？

In the above code, is (2) okay? Can I use smart pointers in Objective-C just like in C++ code? And can I assume the Test class destructor will be called when the MyClass object is destroyed?

或者，如果（2）是不行的在Objective-C ++，是（1）行不行？我会需要手动调用
在的dealloc ？

Or if (2) is not okay in Objective-C++, is (1) okay? Would I need to manually call delete m_testObjectPtr in dealloc?

推荐答案

您只能在C ++类使用智能指针。如果你对Objective-C类，然后使用你要么得到的地方编译错误或崩溃。结果
您还可以使用与Objective-C类的指针容器，如

You can use smart pointer only on c++ classes. if you use then on objective-c classes you will either get compile error or crash somewhere.
You can also use containers with pointers of objective-c classes like

std::vector<CCSprite *> spriteList;

只要确保你留住他们，当你插入它们列出并释放他们，当你删除它们。结果
在这两种情况下，你可以让你自己的呼叫保留了智能指针，并在构造函数/自毁发布/复制一样需要再不用担心保留的释放。结果
此外析构函数成员C ++对象会被自动调用，当对象被释放。结果
客观C包装的一个例子是

just make sure you retain them when you insert them to list and release them when you remove them.
In both cases, you can make a smart pointer of your own that calls retain and release in constructor/destruct/copy like needed and then don't worry about retain release.
Also destructor for member c++ objects will be called automatically when the object is deallocated.
An example of an objective c wrapper would be

template<typename T>
struct shared_objc_object
{
    T *Object;
    shared_objc_object : Object(nil) { }
    shared_objc_object(T *Object) : Object([Object retain]) { }
    shared_objc_object(shared_objc_object &other) :
        Object([other.Object retain]) { }
    ~shared_objc_object() { [Object release]; }
    shared_objc_object &operator =(shared_objc_object &other)
    {
        [Object release];
        Object = [other.Object retain];
    }
}

您还可以使用

std::vector<shared_objc_object<CCSprite *>> spriteList;
spriteList.push_back(some_sprite);

和不关心保留/释放

这篇关于混合C ++和Objective-C的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！