多参selector

本文出自 “林家男孩” 博客，请务必保留此出处http://bj007.blog.51cto.com/1701577/538995 

1 Selector是Objective-C一个非常强大的特性，合理使用Selector可以大大简化实现并避免重复代码。但NSObject提供 的performSelector最多只支持两个参数，对于两个以上的参数就无能为力了。一番调查后针对NSObject增加了如下扩展，使得 performSelector可以支持传入参数数组。多个参数就不再是问题了。
 2 @interface NSObject (Addition)
 3 
 4 - (id)performSelector:(SEL)selector withObjects:(NSArray *)objects;
 5 
 6 @end
 7 
 8 @implementation NSObject (Addition)
 9 
10 - (id)performSelector:(SEL)selector withObjects:(NSArray *)objects { 
11     NSMethodSignature *signature = [self methodSignatureForSelector:selector]; 
12     if (signature) { 
13         NSInvocation* invocation = [NSInvocation invocationWithMethodSignature:signature]; 
14         [invocation setTarget:self]; 
15         [invocation setSelector:selector]; 
16         for(int i = 0; i < [objects count]; i++){ 
17             id object = [objects objectAtIndex:i]; 
18             [invocation setArgument:&object atIndex: (i + 2)];        
19         } 
20         [invocation invoke]; 
21         if (signature.methodReturnLength) { 
22             id anObject; 
23             [invocation getReturnValue:&anObject]; 
24             return anObject; 
25         } else { 
26             return nil; 
27         } 
28     } else { 
29         return nil; 
30     } 
31 } 
32 @end

 

 然后再膜拜辉哥