how to pass variable arguments to another method?
i have googled and came to know that how to use the variable arguments. but i want to pass my variable arguments to another method. i m getting errors. how to do that ?
-(void) aMethod:(NSString *) a, ... {
[self anotherMethod:a];
// i m doing this but getting error. how to pass complete vararg to anotherMethod
}
AFAIK ObjectiveC (just like C and C++) do not provide you with a syntax that allows what you directly have in mind.
The usual workaround is to create two versions of a function. One that may be called directly using ... and another one called by others functions passing the parameters in form of a va_list.
.. [obj aMethod:@"test this %d parameter", 1337); [obj anotherMethod:@"test that %d parameter", 666); .. -(void) aMethod:(NSString *)a, ... { va_list ap; va_start(ap, a); [self anotherMethod:a withParameters:ap]; va_end(ap); } -(void) anotherMethod:(NSString *)a, ... { va_list ap; va_start(ap, a); [self anotherMethod:a withParameters:ap]; va_end(ap); } -(void) anotherMethod:(NSString *)a withParameters:(va_list)valist { NSLog([[[NSString alloc] initWithFormat:a arguments:valist] autorelease]); }
You cannot pass variadic arguments directly. But some of these methods provide an alternative that you can pass a va_list
argument e.g.
#include <stdarg.h>
-(void)printFormat:(NSString*)format, ... {
// Won't work:
// NSString* str = [NSString stringWithFormat:format];
va_list vl;
va_start(vl, format);
NSString* str = [[[NSString alloc] initWithFormat:format arguments:vl] autorelease];
va_end(vl);
printf("%s", [str UTF8String]);
}
Have you considered setting up your arguments in either an array or dictionary, and coding conditionally?
-(void) aMethodWithArguments:(NSArray *)arguments {
for (id *object in arguments) {
if ([object isKindOfClass:fooClass]) {
//handler for objects that are foo
[self anotherMethod:object];
}
if ([object isKindOfClass:barClass]) {
//and so on...
[self yetAnotherMethod:object];
}
}
}