在Objective C中,创建一个具有无限参数的方法(如NSLog)的语法是什么？

Question

我需要编写一个Objective-C方法,其输入是一个字符串数组,其输出是连接的字符串列表,但只有那些不是nil的字符串.

任何想法,如果这个功能已经在基础的某个地方？

如果还没有完成,我怎样才能编写一个具有无限数量的NSString参数的方法？例如,像C#中的params关键字一样,它实质上将params列表转换为数组.

谢谢

Answer 1

你需要...(省略号):

- yourMessage:arg1, ...;

这是关于该主题的官方Apple信息.

我在这里复制他们的样本:

#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