在编译期间确定目标名称

Question

我有几个目标，根据它们我需要导入标题。我可以通过定义一些预处理器值然后用#ifdef来检查它，但我想知道，如果有任何方法可以做类似的事情：

#if TARGET_NAME = "FirstTarget"
#import "SomeHeader.h"
#endif

Answer 1

你可以使用如下，例如，

//Your current target's are defined
#define FIRST_TARGET   "FirstTarget"
#define SECOND_TARGET  "SecondTarget"
#define THIRD_TARGET   "ThirdTarget"  

//set which target u want to run
#define TARGET_NAME   FIRST_TARGET //SECOND_TARGET //THIRD_TARGET

//use like below

#if (TARGET_NAME == FIRST_TARGET) //or u can directly specify name instead of defining at the beginning
   #import "SomeHeader.h"
   //other headers
#elif (TARGET_NAME == SECOND_TARGET)
   //header to be in second target
#elif (TARGET_NAME == THIRD_TARGET)
   // other header
#endif

修改

我知道了，它给出了错误，因为宏不会比较变量长度值，有关详细信息，请参阅此hear。

所以为了工作你可以像下面一样改变它，

//Your current target's are defined, instead of strings give some constant values
#define FIRST_TARGET   1//@"FirstTarget"
#define SECOND_TARGET  2//@"SecondTarget"
#define THIRD_TARGET   3//@"ThirdTarget"

//set which target u want to run 
#define TARGET_NAME   FIRST_TARGET //SECOND_TARGET //THIRD_TARGET

//use like below
#if TARGET_NAME == FIRST_TARGET
#import "SomeHeader.h"
//other headers
#elif (TARGET_NAME == SECOND_TARGET)
//header to be in second target
#elif (TARGET_NAME == THIRD_TARGET)
// other header

#endif