如何将nil-terminted字符串列表传递给Objective-C函数？

Question

函数[NSArray arrayWithObjects:foo,bar,nil]将一个nil-terminted字符串列表传递给一个函数.

如果我想编写一个类似的函数,声明是什么样的,我如何遍历字符串？

Answer 1

我引用http://developer.apple.com/mac/library/qa/qa2005/qa1405.html,其中包含完整的真相.

这是一个Objective-C类的示例,其中包含一个可变方法,该方法将nil终止的参数列表中的所有对象附加到NSMutableArray实例:

#import <Cocoa/Cocoa.h>

@interface NSMutableArray (variadicMethodExample)

- (void) appendObjects:(id) firstObject, ...;  // This method takes a nil-terminated list of objects.

@end

@implementation NSMutableArray (variadicMethodExample)

- (void) appendObjects:(id) firstObject, ...
{
id eachObject;
va_list argumentList;
if (firstObject)                      // The first argument isn't part of the varargs list,
  {                                   // so we'll handle it separately.
  [self addObject: firstObject];
  va_start(argumentList, firstObject);          // Start scanning for arguments after firstObject.
  while (eachObject = va_arg(argumentList, id)) // As many times as we can get an argument of type "id"
    [self addObject: eachObject];               // that isn't nil, add it to self's contents.
  va_end(argumentList);
  }
}

@end