performSelector,带多个参数,NSInvocation, NSMethodSignature

- (id)performSelector:(SEL)aSelector withObject:(id)object1 withObject:(id)object2  这样可以带俩参数

如果我使用[self performSelectorInBackground:@selector(function:withOther:

) withObject:xxx];

XXX该怎么写呢，我试过[NSArray arrayWithObjects:@"a", @"b", nil],直接crash

- (void)function:(NSString *)one withOther:(NSString *)two;

NSString *string1 = @\"111\";

02. 

03.NSString *string2 = @\"222\";

04. 

05.NSMethodSignature *sig = [self methodSignatureForSelector:@selector(function:withOther:)];

06. 

07.NSInvocation *invocation = [NSInvocation invocationWithMethodSignature:sig];

08. 

09.[invocation setTarget:self];

10. 

11.[invocation setSelector:@selector(function:withOther:)];

12. 

13.[invocation setArgument:&string1 atIndex:2];

14. 

15.[invocation setArgument:&string2 atIndex:3];

16. 

17.[invocation performSelectorInBackground:@selector(invoke) withObject:nil];