如何从Objective-C向C++函数发送数组

Question

我试图从Objective-C向C++中的函数发送一个NSMutableArray，甚至两个字符串，但没有成功。 从C++将一个字符串返回到Objective-C，我没有任何问题，但我感到困惑的是另一种方式。 下面是我从C++获取字符串的代码:

WrapperClass.h

#ifndef WrapperClass_hpp
#define WrapperClass_hpp

#include <stdio.h>
#include <stdlib.h>

@interface WrapperClass : NSObject
@end

@interface WrapperClass ()
- (NSString *)getHelloString;
- (NSMutableArray *)sendInfo :(NSString *)str1 :(NSString *)str2; 

// the array above is what I want to send to C++

@end

#endif /* WrapperClass_h */

WrapperClass.mm

#import <Foundation/Foundation.h>

#import "WrapperClass.h"
#include "WrapperClass.h"
#include "CppClass.h"

using namespace test;

@interface WrapperClass ()
@property (nonatomic) HelloTest helloTest;
@end

@implementation WrapperClass

- (NSString *)getHelloString {
    self.helloTest = *(new HelloTest);
    std::string str = self.helloTest.getHelloString();
    NSString* result = [[NSString alloc] initWithUTF8String:str.c_str()];
    return result;
}

- (NSMutableArray *)sendInfo :(NSString *)str1 :(NSString *)str2 {
    std::string str1 = std::string([str1 UTF8String]);
    std::string str1 = std::string([str2 UTF8String]);
    std::array<std::string, 2> myArray = {{ str1, str2 }};

// Not sure how to send to CPP ...

}

cppclass.h

#ifndef Cpp_Class_h
#define Cpp_Class_h

#include <stdio.h>
#include <string>
#include <array>

using namespace std;

namespace test {
    class HelloTest {
    public:
        std::string getHelloString();
    };
}
#endif 

cppClass.cpp

std::string test::HelloTest::getHelloString() {
    std::string outString = "Hello World!";
    return outString;
}

// this code gets the string from c++, but how to 
// send two strings or an array to a function?

Answer 1

根据我的意见，保持指向C++类的指针:

@interface WrapperClass ()
@property (nonatomic) HelloTest* helloTest;
@end

最好还是考虑使用std::unique_ptr 来管理内存。

在C++类中添加set方法（省略实现）:

namespace test {
    class HelloTest {
    public:
        std::string getHelloString() const;    // Add const!
        void setHelloStrings(const std::array<std::string>& strings);
    };
}

然后像这样从Objective-C++中传递它:

- (NSMutableArray *)sendInfo :(NSString *)str1 :(NSString *)str2 {
    std::string str1 = std::string([str1 UTF8String]);
    std::string str1 = std::string([str2 UTF8String]);
    std::array<std::string, 2> myArray = {{ str1, str2 }};
    self.helloTest->setHelloStrings(myArray);
}