如何從本機iOS插件返回字符串到統一？

Question

我正在創建一個需要將字符串（或const char *）返回給Unity的iOS插件。我如何實現它？

Answer 1

extern "C" 
{ 
    int _pow2(int x) 
    { 
     // Just a simple example of returning an int value 
     return x * x; 
    } 

    // Returns a char* (a string to Unity) 
    char* _helloWorldString() 
    { 
     // We can use NSString and go to the c string that Unity wants 
     NSString *helloString = @"Hello World"; 
     // UTF8String method gets us a c string. Then we have to malloc a copy to give to Unity. I reuse a method below that makes it easy. 
     return cStringCopy([helloString UTF8String]); 
    } 

    // Here is an example of getting a string from Unity 
    char* _combineStrings(const char* cString1, const char* cString2) 
    { 
     // This shows we can create two NSStrings* from the c strings from Unity 
     NSString *string1 = CreateNSString(cString1); 
     NSString *string2 = CreateNSString(cString2); 
     NSString *combinedString = [NSString stringWithFormat:@"%@ %@", string1, string2]; 
     // Same as before, have to go to a c string and then malloc a copy of it to give to Unity 
     return cStringCopy([combinedString UTF8String]); 
    } 
} 

//I also like to include these two convenience methods to convert between c string and NSString*. You need to return a copy of the c string so that Unity handles the memory and gets a valid value. 

char* cStringCopy(const char* string) 
{ 
    if (string == NULL) 
     return NULL; 

    char* res = (char*)malloc(strlen(string) + 1); 
    strcpy(res, string); 

    return res; 
} 

// This takes a char* you get from Unity and converts it to an NSString* to use in your objective c code. You can mix c++ and objective c all in the same file. 
static NSString* CreateNSString(const char* string) 
{ 
    if (string != NULL) 
     return [NSString stringWithUTF8String:string]; 
    else 
     return [NSString stringWithUTF8String:""]; 
} 

在問一個問題之前，您應該嘗試詢問Google。

來源：I found this code here